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The Role of Adjuvant Radiation in the Management of Solitary Fibrous Tumors of the Central Nervous System
E102
International Journal of Radiation Oncology Biology Physics
Purpose/Objective(s): Immune check point therapy is increasingly incorporated in the management of metastatic melanoma patients, including those with brain metastases, but the optimal timing of immunotherapy with stereotactic radiosurgery (SRS) or hypofractionated RT with respect to clinical outcome remains unclear. This study sought to determine the temporal significance of immunotherapy in melanoma patients treated with RT for brain metastases. Materials/Methods: We retrospectively reviewed a single institution’s experience of consecutive melanoma patients undergoing first course of RT and an immune checkpoint agent between 2008-2015. Patients receiving whole brain radiation therapy (WBRT) were excluded. Patients were required to have measurable disease, pre-treatment MRI, and early (<100 days after RT) post-treatment MRI. Concurrent therapy was defined as RT within 30 days of immunotherapy administration. Patient, treatment and imaging data were reviewed. Early distant brain progression was defined as new enhancing lesion or >20% increase in one-dimensional measurements of a non-treated lesion; this excluded lesions treated with RT. Data was analyzed using proportional hazards modeling and Fisher’s exact test. Results: We identified 82 melanoma patients with 144 metastases and median age 65 (range 21-88); 91% had extracranial disease, and 79% had ECOG performance status 0-1. Surgical resection was performed in 16 (19.5%) patients prior to RT. Median RT dose was 18Gy (range 15-39Gy). Concurrent immunotherapy was used in 36 (43.9%) patients including 26 patients receiving ipilimumab and 8 patients receiving pembrolizumab. Among patients receiving concurrent therapy, 58.3% developed early distant brain progression vs. 34.8% of patients not receiving concurrent therapy (pZ0.045 by two-tailed Fisher’s exact test). The change of the sum of one-dimensional measurements of lesions treated by RT did not differ between patients receiving concurrent vs. those who did not (p>0.05). On multivariate analysis, overall survival was significantly associated with ECOG performance status 0-1 (AHR 0.41, pZ0.004), concurrent immunotherapy (AHR 0.48, pZ0.020), and early distant brain progression (AHR 3.26, p<0.001). Conclusion: In our cohort, melanoma patients with brain metastases receiving concurrent immunotherapy and cranial RT were more likely to exhibit early distant brain progression. Interestingly, while early distant brain progression was associated with worse survival, concurrent immunotherapy and cranial RT was associated with improved survival compared to patients who did not receive it concurrently. The explanation of this data is not immediately clear, however these findings are hypothesis generating. Prospective studies are required to clarify these retrospective findings. Author Disclosure: R. Rahman: None. A. Cortes: None. K.S. Oh: Research Grant; Elekta, Merck & Co., Inc.. Review and create questions for CME section of journal; IJROBP. K.T. Flaherty: None. D.P. Lawrence: None. R.J. Sullivan: None. H.A. Shih: Employee; Dartmouth Hitchcock. Honoraria; International Journal of Radiation Oncology, UpToDate. Advisory Board; Genentech. clinical operarions director; MGH Proton Therapy Center. clinical operational leader; Massachusetts General Hospital. editor; International Journal of Radiation Oncology. hospital site residency program director; Harv.
between 2003 and 2011. Of the 177 cases identified, <10 patients received no treatment or radiation alone. The final cohort consisted of 155 patients who received surgery and had adequate information for analysis. Descriptive statistics, logistic regression, and single (Kaplan-Meier) and multivariable (Cox proportional hazards) survival analyses, were performed using SAS. Significance was calculated using a t-test, Fisher’s exact test, chi-square, log-rank test, or Cox model. Results: A total of 155 patients met selection criteria; 23 (15%) underwent both surgery and adjuvant radiation while 132 (85%) underwent surgery alone. The treatment groups had comparable demographics and tumor size; median age 53 (range 25-80) and 11 females (48%) in the surgery and adjuvant radiation group, compared to 55 (20-89) and 71 (54%) in the surgery alone group, respectively. Modes of radiotherapy for treatment utilized conventional and stereotactic dose and fractionations schemes. Information on margin status and re-resection rates were not available. No variables were associated with receipt of adjuvant radiation. In single (pZ0.78) and multivariable (pZ0.86) survival analysis, the addition of adjuvant radiation did not significantly affect overall survival. Five-year overall survival was 88% with surgery alone versus 93% with adjuvant radiation. Conclusion: Solitary fibrous tumors are rare neoplasms, especially in the CNS. Our study did not demonstrate an overall survival benefit for adjuvant radiation. The primary treatment modality is surgery, with an unclear role for adjuvant radiation. Author Disclosure: N. Rana: None. E. Kim: None. J.J. Jaboin: None. A. Attia: Employee; Vanderbilt University. Honoraria; Brainlab, qfix. Travel Expenses; qfix. ; American Cancer Society, Vanderbilt University.
2241 The Role of Adjuvant Radiation in the Management of Solitary Fibrous Tumors of the Central Nervous System N. Rana,1 E. Kim,1 J.J. Jaboin,2 and A. Attia1; 1Department of Radiation Oncology, Vanderbilt University Medical Center, Nashville, TN, 2Oregon Health & Science University, Portland, OR Purpose/Objective(s): Solitary fibrous tumors (SFT) are a rare neoplasm of mesenchymal origin, typically arising from serosal membranes, deep soft tissues, and meningeal dura. Although historically thought to be intrathoracic tumors, a majority of SFTs originate outside of the thorax, especially in the central nervous system (CNS). There is limited evidence on the epidemiology, treatment, and outcomes of this disease. Materials/Methods: The national cancer database (NCDB) was queried for patients diagnosed with a SFT in the CNS as their only tumor diagnosis
2242 The Effect of Vertebral Endplate Involvement on Spine Radiosurgery Outcomes Z. Rana,1 M. Ghaly,2 K.D. Kelley,3 R. Meshrekey,4 and J.P. Knisely1; 1 Northwell Health, Lake Success, NY, 2Department of Radiation Medicine, Northwell Health, Lake Success, NY, 3Northwell Health, Manhasset, NY, 4 New York Institute of Technology College of Osteopathic Medicine, Glen Head, NY Purpose/Objective(s): This study sought to evaluate local and adjacent vertebral body outcomes in patients treated with spine radiosurgery. The relationship between vertebral endplate involvement and clinical outcomes was also analyzed. Materials/Methods: 156 patients (361 spine segments and 452 endplates) with spine tumors treated with stereotactic body radiotherapy from January 2010 to December 2015 were retrospectively reviewed. Initial treatment fields were based on ASTRO consensus guidelines. Cox regression analysis was performed to search for possible predicting factors for time to local and adjacent vertebral body failure. Factors included endplate involvement, extraspinal extension of metastatic disease, fraction number, tumor histology (radioresistant vs. radiosensitive), performance status and gender. Results: Median patient age was 66 years (range, 17-91 years), median follow-up was 7 months (range, 1-61 months). 16.8% of endplates reviewed had tumor involvement and fracture rate after radiosurgery was 7.5%. The overall local control rate was 85% at 6 months and 76% at 1 year. 57% of vertebral bodies received single fraction treatment (13-20 Gy), while 34% received three fraction treatment (range, 16-27 Gy), and 9% received five fraction treatment (25-40 Gy). Single fraction treatment was superior in terms of local control (p<0.05). Endplate involvement was significantly associated with adjacent vertebral body involvement (p<.05) and had a positive predictive value of 26%, and a mean time to adjacent failure of 23.5 months. Conclusion: Radiosurgery can achieve durable radiologic control of metastatic spinal disease with minimal toxicity. Endplate involvement may serve as a positive predictor for adjacent tumor spread. Author Disclosure: Z. Rana: None. M. Ghaly: None. K.D. Kelley: None. R. Meshrekey: None. J.P. Knisely: ; ASTRO annual meeting CNS Track, ASTRO Annual Meeting Scientific Committee.
International Journal of Radiation Oncology Biology Physics
Purpose/Objective(s): Immune check point therapy is increasingly incorporated in the management of metastatic melanoma patients, including those with brain metastases, but the optimal timing of immunotherapy with stereotactic radiosurgery (SRS) or hypofractionated RT with respect to clinical outcome remains unclear. This study sought to determine the temporal significance of immunotherapy in melanoma patients treated with RT for brain metastases. Materials/Methods: We retrospectively reviewed a single institution’s experience of consecutive melanoma patients undergoing first course of RT and an immune checkpoint agent between 2008-2015. Patients receiving whole brain radiation therapy (WBRT) were excluded. Patients were required to have measurable disease, pre-treatment MRI, and early (<100 days after RT) post-treatment MRI. Concurrent therapy was defined as RT within 30 days of immunotherapy administration. Patient, treatment and imaging data were reviewed. Early distant brain progression was defined as new enhancing lesion or >20% increase in one-dimensional measurements of a non-treated lesion; this excluded lesions treated with RT. Data was analyzed using proportional hazards modeling and Fisher’s exact test. Results: We identified 82 melanoma patients with 144 metastases and median age 65 (range 21-88); 91% had extracranial disease, and 79% had ECOG performance status 0-1. Surgical resection was performed in 16 (19.5%) patients prior to RT. Median RT dose was 18Gy (range 15-39Gy). Concurrent immunotherapy was used in 36 (43.9%) patients including 26 patients receiving ipilimumab and 8 patients receiving pembrolizumab. Among patients receiving concurrent therapy, 58.3% developed early distant brain progression vs. 34.8% of patients not receiving concurrent therapy (pZ0.045 by two-tailed Fisher’s exact test). The change of the sum of one-dimensional measurements of lesions treated by RT did not differ between patients receiving concurrent vs. those who did not (p>0.05). On multivariate analysis, overall survival was significantly associated with ECOG performance status 0-1 (AHR 0.41, pZ0.004), concurrent immunotherapy (AHR 0.48, pZ0.020), and early distant brain progression (AHR 3.26, p<0.001). Conclusion: In our cohort, melanoma patients with brain metastases receiving concurrent immunotherapy and cranial RT were more likely to exhibit early distant brain progression. Interestingly, while early distant brain progression was associated with worse survival, concurrent immunotherapy and cranial RT was associated with improved survival compared to patients who did not receive it concurrently. The explanation of this data is not immediately clear, however these findings are hypothesis generating. Prospective studies are required to clarify these retrospective findings. Author Disclosure: R. Rahman: None. A. Cortes: None. K.S. Oh: Research Grant; Elekta, Merck & Co., Inc.. Review and create questions for CME section of journal; IJROBP. K.T. Flaherty: None. D.P. Lawrence: None. R.J. Sullivan: None. H.A. Shih: Employee; Dartmouth Hitchcock. Honoraria; International Journal of Radiation Oncology, UpToDate. Advisory Board; Genentech. clinical operarions director; MGH Proton Therapy Center. clinical operational leader; Massachusetts General Hospital. editor; International Journal of Radiation Oncology. hospital site residency program director; Harv.
between 2003 and 2011. Of the 177 cases identified, <10 patients received no treatment or radiation alone. The final cohort consisted of 155 patients who received surgery and had adequate information for analysis. Descriptive statistics, logistic regression, and single (Kaplan-Meier) and multivariable (Cox proportional hazards) survival analyses, were performed using SAS. Significance was calculated using a t-test, Fisher’s exact test, chi-square, log-rank test, or Cox model. Results: A total of 155 patients met selection criteria; 23 (15%) underwent both surgery and adjuvant radiation while 132 (85%) underwent surgery alone. The treatment groups had comparable demographics and tumor size; median age 53 (range 25-80) and 11 females (48%) in the surgery and adjuvant radiation group, compared to 55 (20-89) and 71 (54%) in the surgery alone group, respectively. Modes of radiotherapy for treatment utilized conventional and stereotactic dose and fractionations schemes. Information on margin status and re-resection rates were not available. No variables were associated with receipt of adjuvant radiation. In single (pZ0.78) and multivariable (pZ0.86) survival analysis, the addition of adjuvant radiation did not significantly affect overall survival. Five-year overall survival was 88% with surgery alone versus 93% with adjuvant radiation. Conclusion: Solitary fibrous tumors are rare neoplasms, especially in the CNS. Our study did not demonstrate an overall survival benefit for adjuvant radiation. The primary treatment modality is surgery, with an unclear role for adjuvant radiation. Author Disclosure: N. Rana: None. E. Kim: None. J.J. Jaboin: None. A. Attia: Employee; Vanderbilt University. Honoraria; Brainlab, qfix. Travel Expenses; qfix. ; American Cancer Society, Vanderbilt University.
2241 The Role of Adjuvant Radiation in the Management of Solitary Fibrous Tumors of the Central Nervous System N. Rana,1 E. Kim,1 J.J. Jaboin,2 and A. Attia1; 1Department of Radiation Oncology, Vanderbilt University Medical Center, Nashville, TN, 2Oregon Health & Science University, Portland, OR Purpose/Objective(s): Solitary fibrous tumors (SFT) are a rare neoplasm of mesenchymal origin, typically arising from serosal membranes, deep soft tissues, and meningeal dura. Although historically thought to be intrathoracic tumors, a majority of SFTs originate outside of the thorax, especially in the central nervous system (CNS). There is limited evidence on the epidemiology, treatment, and outcomes of this disease. Materials/Methods: The national cancer database (NCDB) was queried for patients diagnosed with a SFT in the CNS as their only tumor diagnosis
2242 The Effect of Vertebral Endplate Involvement on Spine Radiosurgery Outcomes Z. Rana,1 M. Ghaly,2 K.D. Kelley,3 R. Meshrekey,4 and J.P. Knisely1; 1 Northwell Health, Lake Success, NY, 2Department of Radiation Medicine, Northwell Health, Lake Success, NY, 3Northwell Health, Manhasset, NY, 4 New York Institute of Technology College of Osteopathic Medicine, Glen Head, NY Purpose/Objective(s): This study sought to evaluate local and adjacent vertebral body outcomes in patients treated with spine radiosurgery. The relationship between vertebral endplate involvement and clinical outcomes was also analyzed. Materials/Methods: 156 patients (361 spine segments and 452 endplates) with spine tumors treated with stereotactic body radiotherapy from January 2010 to December 2015 were retrospectively reviewed. Initial treatment fields were based on ASTRO consensus guidelines. Cox regression analysis was performed to search for possible predicting factors for time to local and adjacent vertebral body failure. Factors included endplate involvement, extraspinal extension of metastatic disease, fraction number, tumor histology (radioresistant vs. radiosensitive), performance status and gender. Results: Median patient age was 66 years (range, 17-91 years), median follow-up was 7 months (range, 1-61 months). 16.8% of endplates reviewed had tumor involvement and fracture rate after radiosurgery was 7.5%. The overall local control rate was 85% at 6 months and 76% at 1 year. 57% of vertebral bodies received single fraction treatment (13-20 Gy), while 34% received three fraction treatment (range, 16-27 Gy), and 9% received five fraction treatment (25-40 Gy). Single fraction treatment was superior in terms of local control (p<0.05). Endplate involvement was significantly associated with adjacent vertebral body involvement (p<.05) and had a positive predictive value of 26%, and a mean time to adjacent failure of 23.5 months. Conclusion: Radiosurgery can achieve durable radiologic control of metastatic spinal disease with minimal toxicity. Endplate involvement may serve as a positive predictor for adjacent tumor spread. Author Disclosure: Z. Rana: None. M. Ghaly: None. K.D. Kelley: None. R. Meshrekey: None. J.P. Knisely: ; ASTRO annual meeting CNS Track, ASTRO Annual Meeting Scientific Committee.