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Frameless linac-based stereotactic radiosurgery (SRS) for brain metastases: analysis of patient repositioning using a mask fixation system and clinical outcomes

Frameless linac-based stereotactic radiosurgery (SRS) for brain metastases: analysis of patient... Purpose: To assess the accuracy of patient repositioning and clinical outcomes of frameless stereotactic radiosurgery (SRS) for brain metastases using a stereotactic mask fixation system. Patients and Methods: One hundred two patients treated consecutively with frameless SRS as primary treatment at University of Rome Sapienza Sant’Andrea Hospital between October 2008 and April 2010 and followed prospectively were involved in the study. A commercial stereotactic mask fixation system (BrainLab) was used for patient immobilization. A computerized tomography (CT) scan obtained immediately before SRS was used to evaluate the accuracy of patient repositioning in the mask by comparing the isocenter position to the isocenter position established in the planning CT. Deviations of isocenter coordinates in each direction and 3D displacement were calculated. Overall survival, brain control, and local control were estimated using the Kaplan-Meier method calculated from the time of SRS. Results: The mean measured isocenter displacements were 0.12 mm (SD 0.35 mm) in the lateral direction, 0.2 mm (SD 0.4 mm) in the anteroposterior, and 0.4 mm (SD 0.6 mm) in craniocaudal direction. The maximum displacement of 2.1 mm was seen in craniocaudal direction. The mean 3D displacement was 0.5 mm (SD 0.7 mm), being maximum 2.9 mm. The median survival was 15.5 months, and 1-year and 2-year survival rates were 58% and 24%, respectively. Nine patients recurred locally after SRS, with 1-year and 2-year local control rates of 91% and 82%, respectively. Stable extracranial disease (P = 0.001) and KPS > 70 (P = 0.01) were independent predictors of survival. Conclusions: Frameless SRS is an effective treatment in the management of patients with brain metastases. The presented non-invasive mask-based fixation stereotactic system is associated with a high degree of patient repositioning accuracy; however, a careful evaluation is essential since occasional errors up to 3 mm may occur. Keywords: stereotactic radiosurgery, positioning reproducibility, isocenter verification, brain metastases Introduction SRS has traditionally been performed using an invasive Stereotactic radiosurgery (SRS) has become increasingly fixed head ring that establishes the stereotactic coordi- used for treatment of patients with brain metastases. Its nates of the target and allows for an accuracy of immo- bilization and positioning less than 1 mm during image efficacy when used alone or in combination with whole brain radiation-therapy (WBRT) has been demonstrated acquisition and treatment. More recently, as an alterna- in several randomized trials and multi-institutional stu- tive to the invasive patient fixation technique, different dies [1-5]. frameless stereotactic systems have been implemented. A variable positioning accuracy of 1-4 mm has been reported for frameless stereotactic systems [6-14], * Correspondence: gminniti@ospedalesantandrea.it reflecting, at least in part, different methods in patient Department of Radiation Oncology, Sant’ Andrea Hospital, University Sapienza, Rome, Italy fixation, positioning, and assessment of accuracy. The Full list of author information is available at the end of the article © 2011 Minniti et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Minniti et al. Radiation Oncology 2011, 6:158 Page 2 of 6 http://www.ro-journal.com/content/6/1/158 use of small margin of safety that must be added to the Table 1 Summary of tumor charaterictiscs and treatment parameters of patients treated with radiosurgery target volume for errors in localization and set-up is essential in order to minimize the potential treatment- No (%) related complications of SRS. Volumes of normal brain Number of patients 102 receiving high dose of radiation are in fact predictive of Median age 64 the development of brain radionecrosis, which is Sex (F/M) 52/50 reported in up to 47% of treated lesions for brain No of lesions per patient volumes larger than 10 cc receiving a dose of 12 Gy 1 lesion 64 (63%) [15]. 2 lesions 24 (23%) Only limited data on tumor control and target locali- 3 lesions 14 (14%) zation have been provided specifically using linac-based Histology frameless devices. In this study, we report our clinical lung 54 (53.5%) experience in patients with brain metastases with the breast 17 (16.5%) use of a commercially available frameless SRS system. In melanoma 14 (13.5%) addition accuracy of target positioning was evaluated others 17(16.5%) using repeat computed tomography (CT) images. Tumor location frontal 31 (20%) Patients and Methods parietal 37 (24%) One hundred two patients treated consecutively with temporal 30 (19%) frameless SRS as primary treatment at University of cerebellar 23 (15%) Rome Sapienza Sant’Andrea Hospital between October occipital 26 (17%) 2008 and April 2010 and followed prospectively were brainstem 7 (5%) involved in the study. Patient characteristics are listed in Radiosurgical dose Table 1. Sixty-four patients were treated for 1 metasta- 20 Gy 86 (56%) sis, 24 patients for 2 metastases, and 14 patients for 3 18 Gy 44 (28%) metastases. The median age at the time of SRS was 64 15-16 24 (16%) years (range 26-81). The most common histologies were Tumor volume (cm ) lung, breast, and melanomas. The most common loca- median 1.6 tion was parietal lobe followed by frontal and temporal range 0.03-16.3 lobe. According to RTOG recursive partitioning analysis Treated volume (cm ) (RPA) classes for brain metastases, 32 patients (31.5%) median 2.2 were in RPA Class I, 58 patients (57%) in RPA Class II, range 0.2-18.8 and12(11.5%)patientsinRPA ClassIII. Patientswere examined clinically one month after SRS and then every 2 months. MRI was made every 2 months in the first the system have been previously described [16]. Before year after the treatment, and then every 3 months or as the CT localization a localizer box was mounted to the appropriate according to the neurological conditions. BrainLAB mask system in order to provide a three- The size of treated lesions was measured in three dimensional (3D) stereotactic coordinate array for target dimensions. Complete and partial response were defined localization. During the procedure the patient was laid as total radiographic disappearance of lesion or decrease on the CT couch with the system secured onto a cus- in tumor volume > 50%. Local progression was defined tom-made platform. CT imaging was performed using as radiographic increase in the size of metastatic lesion. the GE 16-slice scanner. CT (General Electric Medical System) scanning was done in spiral mode using a pitch SRS procedure of 0.75, 512 × 512 pixel size, and slices in thickness and After obtained informed consent, patients underwent spacing of 1.2 mm acquired throughout the entire cra- contrast-enhanced T1-weighted magnetic resonance nium.Tubevoltage andtubepotential were setat130 imaging (MRI) (26 cm FOV, 512 × 512 pixel size, 1 mm kV and 300 mA to obtain high quality reconstructed slice interval) using a 1.5 Tesla MRI (Siemens Sonata, slices. Siemens Medical Systems, Erlangen, Germany). Patient The MRI and planning CT datasets were imported immobilization was achieved by using the commercially into the BrainLab planning system and stereotactic available BrainLab head mask fixation system. In addi- coordinates localization were performed by the software tion, a mouth bite positioned against the upper denti- by identifying the location of six localizer rods on the tion attached to the stereotactic frame was applied to outside surfaces of the right, left, and anterior walls of prevent any head tilt movement. The characteristics of the localizer box. Localization establishes the 3D Minniti et al. Radiation Oncology 2011, 6:158 Page 3 of 6 http://www.ro-journal.com/content/6/1/158 stereotactic coordinate system for treatment planning mean ± standard deviation (SD) for all patients. The 3D and delivery. The target volume was identified on the displacement determined by the square root of the sum basis of the fused CT and magnetic resonance (MR) of squares of the displacements seen in the 3 directions images. The gross tumor volume (GTV) was delineated was calculated. Analysis of subgroups was performed as a contrast-enhancing tumor demonstrated on MRI using the log-rank test, and p = 0.05 was the criterion scans. CTV was considered the same as GTV. The plan- for statistical significance. ning target volume (PTV) was generated by the geo- metric expansion of GTV plus 1.0 mm. Radiosurgical Results dose was 20 Gy for metastases with a volume ≤ 4.3 cm Accuracy of positioning (corresponding to a sphere of 2 cm in diameter), 18 Gy The relocation accuracy of the isocenter determined for metastases with a volume of 4.3-14.1 cm ,and 16 from CT verification before the treatment is shown in Gy for metastases with a volume > 14.1 cm .Doses Table 2. The mean measured isocenter displacements were prescribed to the 80-90% isodose line normalized were 0.12 mm (SD 0.35 mm) in the lateral direction, 0.2 to the maximum dose. All radiation doses were deliv- mm (SD 0.4 mm) in the anteroposterior, and 0.4 mm ered in a single fraction with 6-10 noncoplanar dynamic (SD 0.6 mm) in craniocaudal direction. The maximum arcs by using a 6-MV LINAC. Patients with multiple displacement of 2.1 mm was seen in craniocaudal direc- lesions often underwent treatment in several sessions tion. The mean 3D displacement was 0.5 mm (SD 0.7 over several days. mm), being maximum 2.9 mm. A 3D displacement more Immediately before treatment, all patients underwent than 1 mm was seen in 31 metastases (20%), being more CT verification to check the accuracy of isocenter posi- than 2 mm in 7 metastases (4.5%), and requiring treat- tion [16]. Firstly, the CT verification set was imported in ment replanning. There was a correlation between devia- the planning system and localized automatically by the tion of isocenters and the position of metastases in the planning software through identification of the stereo- brain, with the maximum 3D displacement observed for tactic fiducials in the same way as for planning CT. metastases located in the cerebellar and frontal lobes Since this step spatially co-registers the stereotactic (cerebellar/frontal lobes versus other lobes, p = 0.02). coordinate systems of planning CT and verification CT A post-treatment CT was made in 60 patients (Table with the respect to the localizer box, errors in patient 3). Patients fitted with the mask were transported in a repositioning result in a shift of anatomical isocenter wheelchair from the treatment room to the CT room. position. In the second step the planning CT and the The mean measured isocenter displacements were 0.04 CT verification were fused. Following fusion, anatomy mm (SD 0.14 mm) in the lateral direction, 0.06 mm (SD was co-registered. Since all brain structures were spa- 0.15 mm) in the anteroposterior direction, and 0.08 mm tially matched, any translation of isocenter position due (SD 0.2 mm) in craniocaudal direction. The mean 3D to patient repositioning error resulted in a mismatch of displacement was 0.09 mm (SD 0.28 mm), with the the localizer rods of the localizer box. As consequence, maximum shift of 0.6 mm. the 3D stereotactic coordinates of isocenter in the verifi- Quality control procedures at the CT scanner, simula- cation CT changed accordingly. Finally, the new isocen- tion room and linear accelerator were routinely per- ter coordinates were recorded, and the isocenter shift formed. The accuracy of coincidence of the radiation between verification and planning CT calculated. isocenter of the treatment unit and the laser-defined room For deviations more than 1 mm the treatment was coordinate system for patient alignment (TC scanner, replanned on the basis of the new isocenter coordinates. simulator and treatment rooms) resulted within 0.8 mm. The whole procedure including verification of isocenter and replanning lasted less than 8 minutes. During this Outcome time patients fitted with the mask were gently and At a median clinical follow-up of 13.5 months (range 2- slowly moved to a wheelchair and transported from CT 32 months) median survival and brain control were 15.5 simulation room to the treatment room, and positioned on the LINAC treatment couch. A post-treatment CT Table 2 Accuracy of isocenter relocation at CT was performed in 60 patients. Differences in isocenter verification position calculated by planning CT and post-treatment Direction (mm) Mean SD Range CT fusion were assumed to serve as an indication of the Cranio-caudal 0.4 0.6 -1,2 - 2.1 stability on the patient’s head within the mask during Medio-lateral 0.12 0.35 -0.9 - 1.4 treatment (intra-fraction motion) and transportation. Anterior-posterior 0.2 0.4 -1,6 - 1.3 Local control and survival from the date of SRS were 3D-displacement 0.5 0.7 0.1-2.9 calculated using the Kaplan-Meier. Deviations of isocen- ter coordinates in each direction were measured as SD, standard deviation Minniti et al. Radiation Oncology 2011, 6:158 Page 4 of 6 http://www.ro-journal.com/content/6/1/158 Table 3 Mean and standard deviation of isocenter (P = 0.006) and number of metastases (P = 0.005) were displacement between CT verification and post-treatment independent predictors on multivariate analysis. No sig- CT nificant prognostic factors were associated with local Direction (mm) Mean SD Range control, however there was a trend toward worse con- Cranio-caudal 0.08 0.2 -0.3 - 0.2 trol for melanoma histology (p = 0.15). Medio-lateral 0.04 0.14 -0.3 - 0.2 Brain radionecrosis, as suggested by MR imaging or Anterior-posterior 0.06 0.15 -0.5 - 0.4 confirmed by histology (n = 9) occurred in 39 (25%) out of 154 treated lesions. Radionecrosis was symptomatic 3D-displacement 0.09 0.28 0-0.6 in 15 patients, being associated with severe neurological SD, standard deviation complications (RTOG Grade 3 and 4) in 7 patients. months and 12 months, respectively (Figure 1). The 1- Discussion year and 2-year survival rates were 67% and 20%, and An essential prerequisite of a frameless stereotactic sys- respective brain control rates were 50% and 21%. Forty- tem is that patient immobilization and positioning are three percent of patients succumbed to their extracra- performed with a high degree of accuracy in order to nial disease and 19% died of progressive intracranial dis- deliver a safe therapeutic radiation dose as for invasive ease. Data were reported to July 2011. At this time 38% frame-based SRS. Different frameless stereotactic sys- of patients were alive. Intracranial tumor progression tems, including infrared camera guidance [17], dental was observed in 60 patients. The 12-month and 24- [18-20], implanted fiducial markers [21,22], and mask month actuarial rates of developing new brain metas- fixation system [6-12] have been developed in the last tases were 43% and 74%, respectively. Nine patients two decades. In our study using a mask-based stereotac- recurred locally after SRS. The 1-year and 2-year local tic system we have evaluated the accuracy of isocenter control rates were 91% and 82%, respectively. Salvage relocation by repeat CT scans. Mean and SD of displa- WBRT was applied in 29 patients and further SRS in 30 cements for each direction were 0.1 mm (SD 0.35 mm) patients. Thirty-seven metastases (24%) had a complete in the mediolateral direction, 0.2 mm (SD 0.4 mm) in response, 59 (38%) had a partial response, and 49 (32%) the anteroposterior direction, and 0.4 mm (SD 0.6 mm) remained stable. A clinical neurological improvement of in the craniocaudal direction. The mean 3D displace- pre-SRS existing symptoms was recorded in 18 out of ment was 0.5 mm (SD 0.7 mm), being maximum 2.9 57 patients (31%) following SRS. mm. Using a similar stereotactic mask fixation system Extracranial disease (P = 0.0001), KPS (P = 0.001), Wong et al. [11] reported a mean and maximum 3D number of metastases (P = 0.01), and RPA class (P = displacements at the isocenter evaluated by CT verifica- 0.0001) were predictive factors for survival. On multi- tion of 0.7 and 2.5 mm, respectively. Fuss et al [13] in a variate analysis stable extracranial disease (P = 0.001) series of 22 patients with 43 cranial lesions have and KPS > 70 (P = 0.01) were associated with the most reported a mean 3D target isocenter translation of 1.64 significant survival benefit. Stable extracranial disease (P ± 0.84 mm, and a maximum dislocation of 3.39 mm, = 0.001), KPS > 70 (P = 0.01), and number of metastases and similar results have been shown by others [7-10]. (1 vs > 1, P = 0.001) were significant predictive factors In our study repeat CT scan with a thickness of 1.2 for brain control; however, only extracranial disease mm and standard high-resolution imaging as the matrix for data acquisition was used to evaluate the accuracy of isocenter relocation. Analysis of repeated CT datasets has the advantage of high resolution imaging as com- pared with portal films [13], although a clear limit of ,8 our procedure is that it can not offer data on real repo- sitioning accuracy on the treatment table. Recent devel- ,6 Overall survival Brain control opment of image-guided frameless radiosurgery systems Local control ,4 include the use of optical image guidanceand X-rayto evaluate patient repositioning with an accuracy of the ,2 system similar to that reported for invasive frames [23-28] An isocenter displacement > 1 mm was found in 0 6 12 18 24 30 36 approximately 20% of treated lesions, being more than 2 Time (months) mm in 4.5% of lesions. Although a margin from GTV to Figure 1 Kaplan-Meier analysis of overall survival, brain PTV expansion of 3 mm could compensate the inaccu- control, and local control. racy of positioning reproducibility reported in our series, Probability Minniti et al. Radiation Oncology 2011, 6:158 Page 5 of 6 http://www.ro-journal.com/content/6/1/158 this will increase the volume of normal brain treated at the ability to use “multisession radiosurgery” to treat high doses (up to 3 times for a lesion of 1.6 cm corre- large lesions. sponding to our median tumor volume) and would Our study has some limitations. Patient relocation likely be unacceptable to avoid serious treatment-related evaluated by comparison of localization and verification complications. Thus, in such patients the treatment was CT scans does not include errors which are related to replanned according to new isocenter coordinates as cal- the treatment unit as laser alignment, machine and culated on the basis of CT verification. The time couch accuracy. Thus, although a margin of 1 mm was associated with an excellent local control and accepata- required for the CT verification was approximately 5 ble toxicity, large series and longer follow-up need to minutes. Another 7 minutes were required for image transfer, identification of the rods, fusion, recalculation confirm the results reported in our series. of isocenter, and replanning. Our verification method In conclusion, the results presented in this study con- allows us to use an expansion from GTV to PTV of 1 firm the high accuracy of patient repositioning with the mm during the planning, and this may have important use of our non-invasive mask-based fixation stereotactic clinical implications. Several studies have in fact shown system. However, a careful evaluation of the reproduci- a significant correlation between normal brain volume bility of patient head position in the mask is essential receiving a dose of 12 Gy and the development of radio- since occasional setup errors up to 3 mm may occur. necrosis in patients treated with SRS for brain metas- The promising results in terms of local control and sur- tases [15,29]. In a series of 310 brain metastases treated vival support the use of linac-based frameless SRS as a with SRS at our institution the actuarial risk of brain common technique in the management of patients with radionecrosis at 1 year was up to 47% for volumes of brain metastases. brainlargerthan10.9cm treated at a dose of 12 Gy, and similar results have been reported by others [29]. In Acknowledgements our current clinical practice the reported procedure per- The authors wish to thanks Mr Davide Mollo, Gianluca Marrone, Matteo mits the use of strict margins for SRS while maintaining Luciani, and Emanuele Tosi for their excellent technical assistance and patient care. an appropriate coverage of the target, and possibly avoiding serious treatment-related complications. Author details The intra-fraction motion is of concern during frame- Department of Radiation Oncology, Sant’ Andrea Hospital, University Sapienza, Rome, Italy. Department of Neuroscience, Neuromed Institute, less SRS. In order to evaluate the motion of the patient’s Pozzilli (IS), Italy. head during the radiosurgical procedure, a post-treat- ment CT was performed in 60 patients. The differences Authors’ contributions GM conceived of the study, participated in its design and coordination, and in isocenter shift calculated by fusing the verification drafted the manuscript. CS and EC carried out the radiosurgical procedures, CT and post-treatment CT represent an indication of and participated in analysis and interpretation of data. MV and MFO the accuracy of patient’s head immobilization during participated in analysis of data and helped to draft the manuscript. RME critically reviewed/revised the article. All authors read and approved the final either treatment or transportation from CT couch to manuscript. the treatment room. The absence of significant move- ments during the different steps of the whole procedure Conflict of interests The authors declare that they have no competing interests. confirms the excellent stability of our mask-based fra- meless systems and justifies its use for SRS. Received: 7 August 2011 Accepted: 16 November 2011 Because the ultimate validity of a procedure is mea- Published: 16 November 2011 sured in terms of clinical results, we have examined References the local control as the most sensitive clinical outcome 1. Pirzkall A, Debus J, Lohr F, Fuss M, Rhein B, Engenhart-Cabillic R, for assessing target accuracy for brain metastases trea- Wannenmacher M: Radiosurgery alone or in combination with whole- ted with frameless SRS. The tumor control of 91% at brain radiotherapy for brain metastases. J Clin Oncol 1998, 16:3563-3569. 2. Andrews DW, Scott CB, Sperduto PW, Flanders AE, Gaspar LE, Schell MC, 12 months and 82% at 24 months is in the best range Werner-Wasik M, Demas W, Ryu J, Bahary JP, Souhami L, Rotman M, reported using other frameless stereotactic systems Mehta MP, Curran WJ Jr: Whole brain radiation therapy with or without [30-32], and confirms that frameless SRS is a viable stereotactic radiosurgery boost for patients with one to three brain metastases: phase III results of the RTOG 9508 randomised trial. Lancet option for patients with brain metastases with an out- 2004, 363:1665-1672. come similar to that observed following frame-based 3. Manon R, O’Neill A, Knisely J, Werner-Wasik M, Lazarus HM, Wagner H, SRS [33-37]. Certainly, frameless SRS has several Gilbert M, Mehta M, Eastern Cooperative Oncology Group: Phase II trial of radiosurgery for one to three newly diagnosed brain metastases from advantages compared with traditional frame-based renal cell carcinoma, melanoma, and sarcoma: an Eastern Cooperative techniques including patient comfort, greater flexibility Oncology Group study (E 6397). J Clin Oncol 2005, 23:8870-8876. in scheduling treatment planning and treatment proce- 4. Aoyama H, Shirato H, Tago M, Nakagawa K, Toyoda T, Hatano K, Kenjyo M, Oya N, Hirota S, Shioura H, Kunieda E, Inomata T, Hayakawa K, Katoh N, dure, possibility to treat multiple lesions in different Kobashi G: Stereotactic radiosurgery plus whole-brain radiation therapy days without the need to reapply a head frame, and Minniti et al. Radiation Oncology 2011, 6:158 Page 6 of 6 http://www.ro-journal.com/content/6/1/158 vs stereotactic radiosurgery alone for treatment of brain metastases: a target localization and patient set-up that combines real-time infrared randomized controlled trial. JAMA 2006, 295:2483-2491. tracking and stereoscopic X-ray imaging. Radiother Oncol 2003, 5. Kocher M, Soffietti R, Abacioglu U, Villà S, Fauchon F, Baumert BG, Fariselli L, 67:129-141. Tzuk-Shina T, Kortmann RD, Carrie C, Hassel MB, Kouri M, Valeinis E, van den 25. Keshavarzi S, Meltzer H, Ben-Haim S, Newman CB, Lawson JD, Levy ML, Berge D, Collette S, Collette L, Mueller RP: Adjuvant whole-brain Murphy K: Initial clinical experience with frameless optically guided radiotherapy versus observation after radiosurgery or surgical resection stereotactic radiosurgery/radiotherapy in pediatric patients. Childs Nerv of one to three cerebral metastases: results of the EORTC 22952-26001 Syst 2009, 25:837-844. study. J Clin Oncol 2011, 29:134-141. 26. Ramakrishna N, Rosca F, Friesen S, Tezcanli E, Zygmanszki P, Hacker F: A 6. Hamilton RJ, Kuchnir FT, Pelizzari CA, Sweeney PJ, Rubin SJ: Repositioning clinical comparison of patient setup and intra-fraction motion using accuracy of a noninvasive head fixation system for stereotactic frame-based radiosurgery versus a frameless image-guided radiosurgery radiotherapy. Med Phys 1996, 23:1909-1917. system for intracranial lesions. Radiother Oncol 2010, 95:109-115. 7. Willner J, Flentje M, Bratengeier K: CT simulation in stereotactic brain 27. Verbakel WF, Lagerwaard FJ, Verduin AJ, Heukelom S, Slotman BJ, radiotherapy–analysis of isocenter reproducibility with mask fixation. Cuijpers JP: The accuracy of frameless stereotactic intracranial Radiother Oncol 1997, 45:83-88. radiosurgery. Radiother Oncol 2010, 97:390-394. 8. Gilbeau L, Octave-Prignot M, Loncol T, Renard L, Scalliet P, Grégoire V: 28. Kelly PJ, Lin YB, Yu AY, Ropper AE, Nguyen PL, Marcus KJ, Hacker FL, Comparison of setup accuracy of three different thermoplastic masks for Weiss SE: Linear accelerator-based stereotactic radiosurgery for the treatment of brain and head and neck tumors. Radiother Oncol 2001, brainstem metastases: the Dana-Farber/Brigham and Women’s Cancer 58:155-162. Center experience. J Neurooncol 2011. 9. Karger CP, Jakel O, Debus J, Kuhn S, Hartmann GH: Three-dimensional 29. Blonigen BJ, Steinmetz RD, Levin L, Lamba MA, Warnick RE, Breneman JC: accuracy and interfractional reproducibility of patient fixation and Irradiated volume as a predictor of brain radionecrosis after linear positioning using a stereotactic head mask system. Int J Radiat Oncol Biol accelerator stereotactic radiosurgery. Int J Radiat Oncol Biol Phys 2010, Phys 2001, 49:1493-1504. 77:996-1001. 10. Salter BJ, Fuss M, Vollmer DG, Sadeghi A, Bogaev CA, Cheek DA, 30. Kamath R, Ryken TC, Meeks SL, Pennington EC, Ritchie J, Buatti JM: Initial Herman TS, Hevezi JM: The TALON removable head frame system for clinical experience with frameless radiosurgery for patients with stereotactic radiosurgery/radiotherapy: measurement of the intracranial metastases. Int J Radiat Oncol Biol Phys 2005, 61:1467-1472. repositioning accuracy. Int J Radiat Oncol Biol Phys 2001, 51:555-562. 31. Breneman JC, Steinmetz R, Smith A, Lamba M, Warnick RE: Frameless 11. Wong VY, Tung SY, Leung TW, Ho KH: CT verification of isocentre image-guided intracranial stereotactic radiosurgery: clinical outcomes for relocatability using stereotactic mask fixation system. Clin Oncol (R Coll brain metastases. Int J Radiat Oncol Biol Phys 2009, 74:702-706. Radiol) 2003, 15:280-287. 32. Nath SK, Lawson JD, Simpson DR, Vanderspek L, Wang JZ, Alksne JF, 12. Baumert BG, Egli P, Studer S, Dehing C, Davis JB: Repositioning accuracy of Ciacci J, Mundt AJ, Murphy KT: Single-isocenter frameless intensity- fractionated stereotactic irradiation: assessment of isocentre alignment modulated stereotactic radiosurgery for simultaneous treatment of for different dental fixations by using sequential CT scanning. Radiother multiple brain metastases: clinical experience. Int J Radiat Oncol Biol Phys Oncol 2005, 74:61-66. 2010, 78:91-97. 13. Fuss M, Salter BJ, Cheek D, Sadeghi A, Hevezi JM, Herman TS: 33. Gerosa M, Nicolato A, Foroni R, Tomazzoli L, Bricolo A: Analysis of long- Repositioning accuracy of a commercially available thermoplastic mask term outcomes and prognostic factors in patients with non-small cell system. Radiother Oncol 2004, 71:339-345. lung cancer brain metastases treated by gamma knife radiosurgery. J 14. Solberg TD, Medin PM, Mullins J, Li S: Quality assurance of immobilization Neurosurg 2005, 102(Suppl):75-80. and target localization systems for frameless stereotactic cranial and 34. Bhatnagar AK, Flickinger JC, Kondziolka D, Lunsford LD: Stereotactic extracranial hypofractionated radiotherapy. Int J Radiat Oncol Biol Phys radiosurgery for four or more intracranial metastases. Int J Radiat Oncol 2008, 71:S131-135. Biol Phys 2006, 64:898-903. 15. Minniti G, Clarke E, Lanzetta G, Osti MF, Trasimeni G, Bozzao A, Romano A, 35. Gaudy-Marqueste C, Regis JM, Muracciole X, Laurans R, Richard MA, Enrici RM: Stereotactic radiosurgery for brain metastases: analysis of Bonerandi JJ, Grob JJ: Gamma-Knife radiosurgery in the management of outcome and risk of brain radionecrosis. Radiat Oncol 2011, 6:48. melanoma patients with brain metastases: a series of 106 patients 16. Minniti G, Valeriani M, Clarke E, D’Arienzo M, Ciotti M, Montagnoli R, without whole-brain radiotherapy. Int J Radiat Oncol Biol Phys 2006, Saporetti F, Enrici RM: Fractionated stereotactic radiotherapy for skull 65:809-816. base tumors: analysis of treatment accuracy using a stereotactic mask 36. Kased N, Binder DK, McDermott MW, Nakamura JL, Huang K, Berger MS, fixation system. Radiat Oncol 2010, 13;5:1. Wara WM, Sneed PK: Gamma Knife radiosurgery for brain metastases 17. Buatti JM, Bova FJ, Friedman WA, Meeks SL, Marcus RB Jr, Mickle JP, Ellis TL, from primary breast cancer. Int J Radiat Oncol Biol Phys 2009, Mendenhall WM: Preliminary experience with frameless stereotactic 75(4):1132-1140. radiotherapy. Int J Radiat Oncol Biol Phys 1998, 42:591-599. 37. Frazier JL, Batra S, Kapor S, Vellimana A, Gandhi R, Carson KA, Shokek O, 18. Kooy HM, Dunbar SF, Tarbell NJ, Mannarino E, Ferarro N, Shusterman S, Lim M, Kleinberg L, Rigamonti D: Stereotactic radiosurgery in the Bellerive M, Finn L, McDonough CV, Loeffler JS: Adaptation and management of brain metastases: an institutional retrospective analysis verification of the relocatable Gill-Thomas-Cosman frame in stereotactic of survival. Int J Radiat Oncol Biol Phys 2010, 76:1486-1492. radiotherapy. Int J Radiat Oncol Biol Phys 1994, 30:685-691. doi:10.1186/1748-717X-6-158 19. Warrington AP, Laing RW, Brada M: Quality assurance in fractionated Cite this article as: Minniti et al.: Frameless linac-based stereotactic stereotactic radiotherapy. Radiother Oncol 1994, 30:239-246. radiosurgery (SRS) for brain metastases: analysis of patient repositioning 20. Rosenthal SJ, Gall KP, Jackson M, Thornton AF Jr: A precision cranial using a mask fixation system and clinical outcomes. Radiation Oncology immobilization system for conformal stereotactic fractionated radiation 2011 6:158. therapy. Int J Radiat Oncol Biol Phys 1995, 33:1239-1245. 21. Jones D, Christopherson DA, Washington JT, Hafermann MD, Rieke JW, Travaglini JJ, Vermeulen SS: A frameless method for stereotactic radiotherapy. Br J Radiol 1993, 66:1142-1150. 22. Kim KH, Cho MJ, Kim JS, Song CJ, Song SH, Kim SH, Myers L, Kim YE: Isocenter accuracy in frameless stereotactic radiotherapy using implanted fiducials. Int J Radiat Oncol Biol Phys 2003, 56:266-273. 23. Ryken TC, Meeks SL, Pennington EC, Hitchon P, Traynelis V, Mayr NA, Bova FJ, Friedman WA, Buatti JM: Initial clinical experience with frameless stereotactic radiosurgery: analysis of accuracy and feasibility. Int J Radiat Oncol Biol Phys 2001, 51:1152-1158. 24. Verellen D, Soete G, Linthout N, Van Acker S, De Roover P, Vinh-Hung V, Van de Steene J, Storme G: Quality assurance of a system for improved http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Radiation Oncology Springer Journals

Frameless linac-based stereotactic radiosurgery (SRS) for brain metastases: analysis of patient repositioning using a mask fixation system and clinical outcomes

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Copyright © 2011 by Minniti et al; licensee BioMed Central Ltd.
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Medicine & Public Health; Oncology; Radiotherapy
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10.1186/1748-717X-6-158
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22085700
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Abstract

Purpose: To assess the accuracy of patient repositioning and clinical outcomes of frameless stereotactic radiosurgery (SRS) for brain metastases using a stereotactic mask fixation system. Patients and Methods: One hundred two patients treated consecutively with frameless SRS as primary treatment at University of Rome Sapienza Sant’Andrea Hospital between October 2008 and April 2010 and followed prospectively were involved in the study. A commercial stereotactic mask fixation system (BrainLab) was used for patient immobilization. A computerized tomography (CT) scan obtained immediately before SRS was used to evaluate the accuracy of patient repositioning in the mask by comparing the isocenter position to the isocenter position established in the planning CT. Deviations of isocenter coordinates in each direction and 3D displacement were calculated. Overall survival, brain control, and local control were estimated using the Kaplan-Meier method calculated from the time of SRS. Results: The mean measured isocenter displacements were 0.12 mm (SD 0.35 mm) in the lateral direction, 0.2 mm (SD 0.4 mm) in the anteroposterior, and 0.4 mm (SD 0.6 mm) in craniocaudal direction. The maximum displacement of 2.1 mm was seen in craniocaudal direction. The mean 3D displacement was 0.5 mm (SD 0.7 mm), being maximum 2.9 mm. The median survival was 15.5 months, and 1-year and 2-year survival rates were 58% and 24%, respectively. Nine patients recurred locally after SRS, with 1-year and 2-year local control rates of 91% and 82%, respectively. Stable extracranial disease (P = 0.001) and KPS > 70 (P = 0.01) were independent predictors of survival. Conclusions: Frameless SRS is an effective treatment in the management of patients with brain metastases. The presented non-invasive mask-based fixation stereotactic system is associated with a high degree of patient repositioning accuracy; however, a careful evaluation is essential since occasional errors up to 3 mm may occur. Keywords: stereotactic radiosurgery, positioning reproducibility, isocenter verification, brain metastases Introduction SRS has traditionally been performed using an invasive Stereotactic radiosurgery (SRS) has become increasingly fixed head ring that establishes the stereotactic coordi- used for treatment of patients with brain metastases. Its nates of the target and allows for an accuracy of immo- bilization and positioning less than 1 mm during image efficacy when used alone or in combination with whole brain radiation-therapy (WBRT) has been demonstrated acquisition and treatment. More recently, as an alterna- in several randomized trials and multi-institutional stu- tive to the invasive patient fixation technique, different dies [1-5]. frameless stereotactic systems have been implemented. A variable positioning accuracy of 1-4 mm has been reported for frameless stereotactic systems [6-14], * Correspondence: gminniti@ospedalesantandrea.it reflecting, at least in part, different methods in patient Department of Radiation Oncology, Sant’ Andrea Hospital, University Sapienza, Rome, Italy fixation, positioning, and assessment of accuracy. The Full list of author information is available at the end of the article © 2011 Minniti et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Minniti et al. Radiation Oncology 2011, 6:158 Page 2 of 6 http://www.ro-journal.com/content/6/1/158 use of small margin of safety that must be added to the Table 1 Summary of tumor charaterictiscs and treatment parameters of patients treated with radiosurgery target volume for errors in localization and set-up is essential in order to minimize the potential treatment- No (%) related complications of SRS. Volumes of normal brain Number of patients 102 receiving high dose of radiation are in fact predictive of Median age 64 the development of brain radionecrosis, which is Sex (F/M) 52/50 reported in up to 47% of treated lesions for brain No of lesions per patient volumes larger than 10 cc receiving a dose of 12 Gy 1 lesion 64 (63%) [15]. 2 lesions 24 (23%) Only limited data on tumor control and target locali- 3 lesions 14 (14%) zation have been provided specifically using linac-based Histology frameless devices. In this study, we report our clinical lung 54 (53.5%) experience in patients with brain metastases with the breast 17 (16.5%) use of a commercially available frameless SRS system. In melanoma 14 (13.5%) addition accuracy of target positioning was evaluated others 17(16.5%) using repeat computed tomography (CT) images. Tumor location frontal 31 (20%) Patients and Methods parietal 37 (24%) One hundred two patients treated consecutively with temporal 30 (19%) frameless SRS as primary treatment at University of cerebellar 23 (15%) Rome Sapienza Sant’Andrea Hospital between October occipital 26 (17%) 2008 and April 2010 and followed prospectively were brainstem 7 (5%) involved in the study. Patient characteristics are listed in Radiosurgical dose Table 1. Sixty-four patients were treated for 1 metasta- 20 Gy 86 (56%) sis, 24 patients for 2 metastases, and 14 patients for 3 18 Gy 44 (28%) metastases. The median age at the time of SRS was 64 15-16 24 (16%) years (range 26-81). The most common histologies were Tumor volume (cm ) lung, breast, and melanomas. The most common loca- median 1.6 tion was parietal lobe followed by frontal and temporal range 0.03-16.3 lobe. According to RTOG recursive partitioning analysis Treated volume (cm ) (RPA) classes for brain metastases, 32 patients (31.5%) median 2.2 were in RPA Class I, 58 patients (57%) in RPA Class II, range 0.2-18.8 and12(11.5%)patientsinRPA ClassIII. Patientswere examined clinically one month after SRS and then every 2 months. MRI was made every 2 months in the first the system have been previously described [16]. Before year after the treatment, and then every 3 months or as the CT localization a localizer box was mounted to the appropriate according to the neurological conditions. BrainLAB mask system in order to provide a three- The size of treated lesions was measured in three dimensional (3D) stereotactic coordinate array for target dimensions. Complete and partial response were defined localization. During the procedure the patient was laid as total radiographic disappearance of lesion or decrease on the CT couch with the system secured onto a cus- in tumor volume > 50%. Local progression was defined tom-made platform. CT imaging was performed using as radiographic increase in the size of metastatic lesion. the GE 16-slice scanner. CT (General Electric Medical System) scanning was done in spiral mode using a pitch SRS procedure of 0.75, 512 × 512 pixel size, and slices in thickness and After obtained informed consent, patients underwent spacing of 1.2 mm acquired throughout the entire cra- contrast-enhanced T1-weighted magnetic resonance nium.Tubevoltage andtubepotential were setat130 imaging (MRI) (26 cm FOV, 512 × 512 pixel size, 1 mm kV and 300 mA to obtain high quality reconstructed slice interval) using a 1.5 Tesla MRI (Siemens Sonata, slices. Siemens Medical Systems, Erlangen, Germany). Patient The MRI and planning CT datasets were imported immobilization was achieved by using the commercially into the BrainLab planning system and stereotactic available BrainLab head mask fixation system. In addi- coordinates localization were performed by the software tion, a mouth bite positioned against the upper denti- by identifying the location of six localizer rods on the tion attached to the stereotactic frame was applied to outside surfaces of the right, left, and anterior walls of prevent any head tilt movement. The characteristics of the localizer box. Localization establishes the 3D Minniti et al. Radiation Oncology 2011, 6:158 Page 3 of 6 http://www.ro-journal.com/content/6/1/158 stereotactic coordinate system for treatment planning mean ± standard deviation (SD) for all patients. The 3D and delivery. The target volume was identified on the displacement determined by the square root of the sum basis of the fused CT and magnetic resonance (MR) of squares of the displacements seen in the 3 directions images. The gross tumor volume (GTV) was delineated was calculated. Analysis of subgroups was performed as a contrast-enhancing tumor demonstrated on MRI using the log-rank test, and p = 0.05 was the criterion scans. CTV was considered the same as GTV. The plan- for statistical significance. ning target volume (PTV) was generated by the geo- metric expansion of GTV plus 1.0 mm. Radiosurgical Results dose was 20 Gy for metastases with a volume ≤ 4.3 cm Accuracy of positioning (corresponding to a sphere of 2 cm in diameter), 18 Gy The relocation accuracy of the isocenter determined for metastases with a volume of 4.3-14.1 cm ,and 16 from CT verification before the treatment is shown in Gy for metastases with a volume > 14.1 cm .Doses Table 2. The mean measured isocenter displacements were prescribed to the 80-90% isodose line normalized were 0.12 mm (SD 0.35 mm) in the lateral direction, 0.2 to the maximum dose. All radiation doses were deliv- mm (SD 0.4 mm) in the anteroposterior, and 0.4 mm ered in a single fraction with 6-10 noncoplanar dynamic (SD 0.6 mm) in craniocaudal direction. The maximum arcs by using a 6-MV LINAC. Patients with multiple displacement of 2.1 mm was seen in craniocaudal direc- lesions often underwent treatment in several sessions tion. The mean 3D displacement was 0.5 mm (SD 0.7 over several days. mm), being maximum 2.9 mm. A 3D displacement more Immediately before treatment, all patients underwent than 1 mm was seen in 31 metastases (20%), being more CT verification to check the accuracy of isocenter posi- than 2 mm in 7 metastases (4.5%), and requiring treat- tion [16]. Firstly, the CT verification set was imported in ment replanning. There was a correlation between devia- the planning system and localized automatically by the tion of isocenters and the position of metastases in the planning software through identification of the stereo- brain, with the maximum 3D displacement observed for tactic fiducials in the same way as for planning CT. metastases located in the cerebellar and frontal lobes Since this step spatially co-registers the stereotactic (cerebellar/frontal lobes versus other lobes, p = 0.02). coordinate systems of planning CT and verification CT A post-treatment CT was made in 60 patients (Table with the respect to the localizer box, errors in patient 3). Patients fitted with the mask were transported in a repositioning result in a shift of anatomical isocenter wheelchair from the treatment room to the CT room. position. In the second step the planning CT and the The mean measured isocenter displacements were 0.04 CT verification were fused. Following fusion, anatomy mm (SD 0.14 mm) in the lateral direction, 0.06 mm (SD was co-registered. Since all brain structures were spa- 0.15 mm) in the anteroposterior direction, and 0.08 mm tially matched, any translation of isocenter position due (SD 0.2 mm) in craniocaudal direction. The mean 3D to patient repositioning error resulted in a mismatch of displacement was 0.09 mm (SD 0.28 mm), with the the localizer rods of the localizer box. As consequence, maximum shift of 0.6 mm. the 3D stereotactic coordinates of isocenter in the verifi- Quality control procedures at the CT scanner, simula- cation CT changed accordingly. Finally, the new isocen- tion room and linear accelerator were routinely per- ter coordinates were recorded, and the isocenter shift formed. The accuracy of coincidence of the radiation between verification and planning CT calculated. isocenter of the treatment unit and the laser-defined room For deviations more than 1 mm the treatment was coordinate system for patient alignment (TC scanner, replanned on the basis of the new isocenter coordinates. simulator and treatment rooms) resulted within 0.8 mm. The whole procedure including verification of isocenter and replanning lasted less than 8 minutes. During this Outcome time patients fitted with the mask were gently and At a median clinical follow-up of 13.5 months (range 2- slowly moved to a wheelchair and transported from CT 32 months) median survival and brain control were 15.5 simulation room to the treatment room, and positioned on the LINAC treatment couch. A post-treatment CT Table 2 Accuracy of isocenter relocation at CT was performed in 60 patients. Differences in isocenter verification position calculated by planning CT and post-treatment Direction (mm) Mean SD Range CT fusion were assumed to serve as an indication of the Cranio-caudal 0.4 0.6 -1,2 - 2.1 stability on the patient’s head within the mask during Medio-lateral 0.12 0.35 -0.9 - 1.4 treatment (intra-fraction motion) and transportation. Anterior-posterior 0.2 0.4 -1,6 - 1.3 Local control and survival from the date of SRS were 3D-displacement 0.5 0.7 0.1-2.9 calculated using the Kaplan-Meier. Deviations of isocen- ter coordinates in each direction were measured as SD, standard deviation Minniti et al. Radiation Oncology 2011, 6:158 Page 4 of 6 http://www.ro-journal.com/content/6/1/158 Table 3 Mean and standard deviation of isocenter (P = 0.006) and number of metastases (P = 0.005) were displacement between CT verification and post-treatment independent predictors on multivariate analysis. No sig- CT nificant prognostic factors were associated with local Direction (mm) Mean SD Range control, however there was a trend toward worse con- Cranio-caudal 0.08 0.2 -0.3 - 0.2 trol for melanoma histology (p = 0.15). Medio-lateral 0.04 0.14 -0.3 - 0.2 Brain radionecrosis, as suggested by MR imaging or Anterior-posterior 0.06 0.15 -0.5 - 0.4 confirmed by histology (n = 9) occurred in 39 (25%) out of 154 treated lesions. Radionecrosis was symptomatic 3D-displacement 0.09 0.28 0-0.6 in 15 patients, being associated with severe neurological SD, standard deviation complications (RTOG Grade 3 and 4) in 7 patients. months and 12 months, respectively (Figure 1). The 1- Discussion year and 2-year survival rates were 67% and 20%, and An essential prerequisite of a frameless stereotactic sys- respective brain control rates were 50% and 21%. Forty- tem is that patient immobilization and positioning are three percent of patients succumbed to their extracra- performed with a high degree of accuracy in order to nial disease and 19% died of progressive intracranial dis- deliver a safe therapeutic radiation dose as for invasive ease. Data were reported to July 2011. At this time 38% frame-based SRS. Different frameless stereotactic sys- of patients were alive. Intracranial tumor progression tems, including infrared camera guidance [17], dental was observed in 60 patients. The 12-month and 24- [18-20], implanted fiducial markers [21,22], and mask month actuarial rates of developing new brain metas- fixation system [6-12] have been developed in the last tases were 43% and 74%, respectively. Nine patients two decades. In our study using a mask-based stereotac- recurred locally after SRS. The 1-year and 2-year local tic system we have evaluated the accuracy of isocenter control rates were 91% and 82%, respectively. Salvage relocation by repeat CT scans. Mean and SD of displa- WBRT was applied in 29 patients and further SRS in 30 cements for each direction were 0.1 mm (SD 0.35 mm) patients. Thirty-seven metastases (24%) had a complete in the mediolateral direction, 0.2 mm (SD 0.4 mm) in response, 59 (38%) had a partial response, and 49 (32%) the anteroposterior direction, and 0.4 mm (SD 0.6 mm) remained stable. A clinical neurological improvement of in the craniocaudal direction. The mean 3D displace- pre-SRS existing symptoms was recorded in 18 out of ment was 0.5 mm (SD 0.7 mm), being maximum 2.9 57 patients (31%) following SRS. mm. Using a similar stereotactic mask fixation system Extracranial disease (P = 0.0001), KPS (P = 0.001), Wong et al. [11] reported a mean and maximum 3D number of metastases (P = 0.01), and RPA class (P = displacements at the isocenter evaluated by CT verifica- 0.0001) were predictive factors for survival. On multi- tion of 0.7 and 2.5 mm, respectively. Fuss et al [13] in a variate analysis stable extracranial disease (P = 0.001) series of 22 patients with 43 cranial lesions have and KPS > 70 (P = 0.01) were associated with the most reported a mean 3D target isocenter translation of 1.64 significant survival benefit. Stable extracranial disease (P ± 0.84 mm, and a maximum dislocation of 3.39 mm, = 0.001), KPS > 70 (P = 0.01), and number of metastases and similar results have been shown by others [7-10]. (1 vs > 1, P = 0.001) were significant predictive factors In our study repeat CT scan with a thickness of 1.2 for brain control; however, only extracranial disease mm and standard high-resolution imaging as the matrix for data acquisition was used to evaluate the accuracy of isocenter relocation. Analysis of repeated CT datasets has the advantage of high resolution imaging as com- pared with portal films [13], although a clear limit of ,8 our procedure is that it can not offer data on real repo- sitioning accuracy on the treatment table. Recent devel- ,6 Overall survival Brain control opment of image-guided frameless radiosurgery systems Local control ,4 include the use of optical image guidanceand X-rayto evaluate patient repositioning with an accuracy of the ,2 system similar to that reported for invasive frames [23-28] An isocenter displacement > 1 mm was found in 0 6 12 18 24 30 36 approximately 20% of treated lesions, being more than 2 Time (months) mm in 4.5% of lesions. Although a margin from GTV to Figure 1 Kaplan-Meier analysis of overall survival, brain PTV expansion of 3 mm could compensate the inaccu- control, and local control. racy of positioning reproducibility reported in our series, Probability Minniti et al. Radiation Oncology 2011, 6:158 Page 5 of 6 http://www.ro-journal.com/content/6/1/158 this will increase the volume of normal brain treated at the ability to use “multisession radiosurgery” to treat high doses (up to 3 times for a lesion of 1.6 cm corre- large lesions. sponding to our median tumor volume) and would Our study has some limitations. Patient relocation likely be unacceptable to avoid serious treatment-related evaluated by comparison of localization and verification complications. Thus, in such patients the treatment was CT scans does not include errors which are related to replanned according to new isocenter coordinates as cal- the treatment unit as laser alignment, machine and culated on the basis of CT verification. The time couch accuracy. Thus, although a margin of 1 mm was associated with an excellent local control and accepata- required for the CT verification was approximately 5 ble toxicity, large series and longer follow-up need to minutes. Another 7 minutes were required for image transfer, identification of the rods, fusion, recalculation confirm the results reported in our series. of isocenter, and replanning. Our verification method In conclusion, the results presented in this study con- allows us to use an expansion from GTV to PTV of 1 firm the high accuracy of patient repositioning with the mm during the planning, and this may have important use of our non-invasive mask-based fixation stereotactic clinical implications. Several studies have in fact shown system. However, a careful evaluation of the reproduci- a significant correlation between normal brain volume bility of patient head position in the mask is essential receiving a dose of 12 Gy and the development of radio- since occasional setup errors up to 3 mm may occur. necrosis in patients treated with SRS for brain metas- The promising results in terms of local control and sur- tases [15,29]. In a series of 310 brain metastases treated vival support the use of linac-based frameless SRS as a with SRS at our institution the actuarial risk of brain common technique in the management of patients with radionecrosis at 1 year was up to 47% for volumes of brain metastases. brainlargerthan10.9cm treated at a dose of 12 Gy, and similar results have been reported by others [29]. In Acknowledgements our current clinical practice the reported procedure per- The authors wish to thanks Mr Davide Mollo, Gianluca Marrone, Matteo mits the use of strict margins for SRS while maintaining Luciani, and Emanuele Tosi for their excellent technical assistance and patient care. an appropriate coverage of the target, and possibly avoiding serious treatment-related complications. Author details The intra-fraction motion is of concern during frame- Department of Radiation Oncology, Sant’ Andrea Hospital, University Sapienza, Rome, Italy. Department of Neuroscience, Neuromed Institute, less SRS. In order to evaluate the motion of the patient’s Pozzilli (IS), Italy. head during the radiosurgical procedure, a post-treat- ment CT was performed in 60 patients. The differences Authors’ contributions GM conceived of the study, participated in its design and coordination, and in isocenter shift calculated by fusing the verification drafted the manuscript. CS and EC carried out the radiosurgical procedures, CT and post-treatment CT represent an indication of and participated in analysis and interpretation of data. MV and MFO the accuracy of patient’s head immobilization during participated in analysis of data and helped to draft the manuscript. RME critically reviewed/revised the article. All authors read and approved the final either treatment or transportation from CT couch to manuscript. the treatment room. The absence of significant move- ments during the different steps of the whole procedure Conflict of interests The authors declare that they have no competing interests. confirms the excellent stability of our mask-based fra- meless systems and justifies its use for SRS. Received: 7 August 2011 Accepted: 16 November 2011 Because the ultimate validity of a procedure is mea- Published: 16 November 2011 sured in terms of clinical results, we have examined References the local control as the most sensitive clinical outcome 1. Pirzkall A, Debus J, Lohr F, Fuss M, Rhein B, Engenhart-Cabillic R, for assessing target accuracy for brain metastases trea- Wannenmacher M: Radiosurgery alone or in combination with whole- ted with frameless SRS. The tumor control of 91% at brain radiotherapy for brain metastases. J Clin Oncol 1998, 16:3563-3569. 2. Andrews DW, Scott CB, Sperduto PW, Flanders AE, Gaspar LE, Schell MC, 12 months and 82% at 24 months is in the best range Werner-Wasik M, Demas W, Ryu J, Bahary JP, Souhami L, Rotman M, reported using other frameless stereotactic systems Mehta MP, Curran WJ Jr: Whole brain radiation therapy with or without [30-32], and confirms that frameless SRS is a viable stereotactic radiosurgery boost for patients with one to three brain metastases: phase III results of the RTOG 9508 randomised trial. Lancet option for patients with brain metastases with an out- 2004, 363:1665-1672. come similar to that observed following frame-based 3. Manon R, O’Neill A, Knisely J, Werner-Wasik M, Lazarus HM, Wagner H, SRS [33-37]. Certainly, frameless SRS has several Gilbert M, Mehta M, Eastern Cooperative Oncology Group: Phase II trial of radiosurgery for one to three newly diagnosed brain metastases from advantages compared with traditional frame-based renal cell carcinoma, melanoma, and sarcoma: an Eastern Cooperative techniques including patient comfort, greater flexibility Oncology Group study (E 6397). J Clin Oncol 2005, 23:8870-8876. in scheduling treatment planning and treatment proce- 4. Aoyama H, Shirato H, Tago M, Nakagawa K, Toyoda T, Hatano K, Kenjyo M, Oya N, Hirota S, Shioura H, Kunieda E, Inomata T, Hayakawa K, Katoh N, dure, possibility to treat multiple lesions in different Kobashi G: Stereotactic radiosurgery plus whole-brain radiation therapy days without the need to reapply a head frame, and Minniti et al. Radiation Oncology 2011, 6:158 Page 6 of 6 http://www.ro-journal.com/content/6/1/158 vs stereotactic radiosurgery alone for treatment of brain metastases: a target localization and patient set-up that combines real-time infrared randomized controlled trial. JAMA 2006, 295:2483-2491. tracking and stereoscopic X-ray imaging. Radiother Oncol 2003, 5. Kocher M, Soffietti R, Abacioglu U, Villà S, Fauchon F, Baumert BG, Fariselli L, 67:129-141. Tzuk-Shina T, Kortmann RD, Carrie C, Hassel MB, Kouri M, Valeinis E, van den 25. Keshavarzi S, Meltzer H, Ben-Haim S, Newman CB, Lawson JD, Levy ML, Berge D, Collette S, Collette L, Mueller RP: Adjuvant whole-brain Murphy K: Initial clinical experience with frameless optically guided radiotherapy versus observation after radiosurgery or surgical resection stereotactic radiosurgery/radiotherapy in pediatric patients. Childs Nerv of one to three cerebral metastases: results of the EORTC 22952-26001 Syst 2009, 25:837-844. study. J Clin Oncol 2011, 29:134-141. 26. Ramakrishna N, Rosca F, Friesen S, Tezcanli E, Zygmanszki P, Hacker F: A 6. Hamilton RJ, Kuchnir FT, Pelizzari CA, Sweeney PJ, Rubin SJ: Repositioning clinical comparison of patient setup and intra-fraction motion using accuracy of a noninvasive head fixation system for stereotactic frame-based radiosurgery versus a frameless image-guided radiosurgery radiotherapy. Med Phys 1996, 23:1909-1917. system for intracranial lesions. Radiother Oncol 2010, 95:109-115. 7. Willner J, Flentje M, Bratengeier K: CT simulation in stereotactic brain 27. Verbakel WF, Lagerwaard FJ, Verduin AJ, Heukelom S, Slotman BJ, radiotherapy–analysis of isocenter reproducibility with mask fixation. Cuijpers JP: The accuracy of frameless stereotactic intracranial Radiother Oncol 1997, 45:83-88. radiosurgery. Radiother Oncol 2010, 97:390-394. 8. Gilbeau L, Octave-Prignot M, Loncol T, Renard L, Scalliet P, Grégoire V: 28. Kelly PJ, Lin YB, Yu AY, Ropper AE, Nguyen PL, Marcus KJ, Hacker FL, Comparison of setup accuracy of three different thermoplastic masks for Weiss SE: Linear accelerator-based stereotactic radiosurgery for the treatment of brain and head and neck tumors. Radiother Oncol 2001, brainstem metastases: the Dana-Farber/Brigham and Women’s Cancer 58:155-162. Center experience. J Neurooncol 2011. 9. Karger CP, Jakel O, Debus J, Kuhn S, Hartmann GH: Three-dimensional 29. Blonigen BJ, Steinmetz RD, Levin L, Lamba MA, Warnick RE, Breneman JC: accuracy and interfractional reproducibility of patient fixation and Irradiated volume as a predictor of brain radionecrosis after linear positioning using a stereotactic head mask system. Int J Radiat Oncol Biol accelerator stereotactic radiosurgery. Int J Radiat Oncol Biol Phys 2010, Phys 2001, 49:1493-1504. 77:996-1001. 10. Salter BJ, Fuss M, Vollmer DG, Sadeghi A, Bogaev CA, Cheek DA, 30. Kamath R, Ryken TC, Meeks SL, Pennington EC, Ritchie J, Buatti JM: Initial Herman TS, Hevezi JM: The TALON removable head frame system for clinical experience with frameless radiosurgery for patients with stereotactic radiosurgery/radiotherapy: measurement of the intracranial metastases. Int J Radiat Oncol Biol Phys 2005, 61:1467-1472. repositioning accuracy. Int J Radiat Oncol Biol Phys 2001, 51:555-562. 31. Breneman JC, Steinmetz R, Smith A, Lamba M, Warnick RE: Frameless 11. Wong VY, Tung SY, Leung TW, Ho KH: CT verification of isocentre image-guided intracranial stereotactic radiosurgery: clinical outcomes for relocatability using stereotactic mask fixation system. Clin Oncol (R Coll brain metastases. Int J Radiat Oncol Biol Phys 2009, 74:702-706. Radiol) 2003, 15:280-287. 32. Nath SK, Lawson JD, Simpson DR, Vanderspek L, Wang JZ, Alksne JF, 12. Baumert BG, Egli P, Studer S, Dehing C, Davis JB: Repositioning accuracy of Ciacci J, Mundt AJ, Murphy KT: Single-isocenter frameless intensity- fractionated stereotactic irradiation: assessment of isocentre alignment modulated stereotactic radiosurgery for simultaneous treatment of for different dental fixations by using sequential CT scanning. Radiother multiple brain metastases: clinical experience. Int J Radiat Oncol Biol Phys Oncol 2005, 74:61-66. 2010, 78:91-97. 13. Fuss M, Salter BJ, Cheek D, Sadeghi A, Hevezi JM, Herman TS: 33. Gerosa M, Nicolato A, Foroni R, Tomazzoli L, Bricolo A: Analysis of long- Repositioning accuracy of a commercially available thermoplastic mask term outcomes and prognostic factors in patients with non-small cell system. Radiother Oncol 2004, 71:339-345. lung cancer brain metastases treated by gamma knife radiosurgery. J 14. Solberg TD, Medin PM, Mullins J, Li S: Quality assurance of immobilization Neurosurg 2005, 102(Suppl):75-80. and target localization systems for frameless stereotactic cranial and 34. Bhatnagar AK, Flickinger JC, Kondziolka D, Lunsford LD: Stereotactic extracranial hypofractionated radiotherapy. Int J Radiat Oncol Biol Phys radiosurgery for four or more intracranial metastases. Int J Radiat Oncol 2008, 71:S131-135. Biol Phys 2006, 64:898-903. 15. Minniti G, Clarke E, Lanzetta G, Osti MF, Trasimeni G, Bozzao A, Romano A, 35. Gaudy-Marqueste C, Regis JM, Muracciole X, Laurans R, Richard MA, Enrici RM: Stereotactic radiosurgery for brain metastases: analysis of Bonerandi JJ, Grob JJ: Gamma-Knife radiosurgery in the management of outcome and risk of brain radionecrosis. Radiat Oncol 2011, 6:48. melanoma patients with brain metastases: a series of 106 patients 16. Minniti G, Valeriani M, Clarke E, D’Arienzo M, Ciotti M, Montagnoli R, without whole-brain radiotherapy. Int J Radiat Oncol Biol Phys 2006, Saporetti F, Enrici RM: Fractionated stereotactic radiotherapy for skull 65:809-816. base tumors: analysis of treatment accuracy using a stereotactic mask 36. Kased N, Binder DK, McDermott MW, Nakamura JL, Huang K, Berger MS, fixation system. Radiat Oncol 2010, 13;5:1. Wara WM, Sneed PK: Gamma Knife radiosurgery for brain metastases 17. Buatti JM, Bova FJ, Friedman WA, Meeks SL, Marcus RB Jr, Mickle JP, Ellis TL, from primary breast cancer. Int J Radiat Oncol Biol Phys 2009, Mendenhall WM: Preliminary experience with frameless stereotactic 75(4):1132-1140. radiotherapy. Int J Radiat Oncol Biol Phys 1998, 42:591-599. 37. Frazier JL, Batra S, Kapor S, Vellimana A, Gandhi R, Carson KA, Shokek O, 18. Kooy HM, Dunbar SF, Tarbell NJ, Mannarino E, Ferarro N, Shusterman S, Lim M, Kleinberg L, Rigamonti D: Stereotactic radiosurgery in the Bellerive M, Finn L, McDonough CV, Loeffler JS: Adaptation and management of brain metastases: an institutional retrospective analysis verification of the relocatable Gill-Thomas-Cosman frame in stereotactic of survival. Int J Radiat Oncol Biol Phys 2010, 76:1486-1492. radiotherapy. Int J Radiat Oncol Biol Phys 1994, 30:685-691. doi:10.1186/1748-717X-6-158 19. Warrington AP, Laing RW, Brada M: Quality assurance in fractionated Cite this article as: Minniti et al.: Frameless linac-based stereotactic stereotactic radiotherapy. Radiother Oncol 1994, 30:239-246. radiosurgery (SRS) for brain metastases: analysis of patient repositioning 20. Rosenthal SJ, Gall KP, Jackson M, Thornton AF Jr: A precision cranial using a mask fixation system and clinical outcomes. Radiation Oncology immobilization system for conformal stereotactic fractionated radiation 2011 6:158. therapy. Int J Radiat Oncol Biol Phys 1995, 33:1239-1245. 21. Jones D, Christopherson DA, Washington JT, Hafermann MD, Rieke JW, Travaglini JJ, Vermeulen SS: A frameless method for stereotactic radiotherapy. Br J Radiol 1993, 66:1142-1150. 22. Kim KH, Cho MJ, Kim JS, Song CJ, Song SH, Kim SH, Myers L, Kim YE: Isocenter accuracy in frameless stereotactic radiotherapy using implanted fiducials. Int J Radiat Oncol Biol Phys 2003, 56:266-273. 23. Ryken TC, Meeks SL, Pennington EC, Hitchon P, Traynelis V, Mayr NA, Bova FJ, Friedman WA, Buatti JM: Initial clinical experience with frameless stereotactic radiosurgery: analysis of accuracy and feasibility. Int J Radiat Oncol Biol Phys 2001, 51:1152-1158. 24. Verellen D, Soete G, Linthout N, Van Acker S, De Roover P, Vinh-Hung V, Van de Steene J, Storme G: Quality assurance of a system for improved

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Radiation OncologySpringer Journals

Published: Nov 16, 2011

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