- Email: [email protected]
Single-Institution Validation of a Graded Prognostic Assessment for Evaluating Breast Cancer Patients With Brain Metastases
E90
International Journal of Radiation Oncology Biology Physics
and normal organ sparing. The 4p plans were initially created using an inhouse beam orientation optimization program and subsequently imported into the clinical treatment planning system for dose recalculation and creation of clinically deliverable plans. A machine and human 3D model were used to eliminate undeliverable beams. In the 4p plans, 14-19 noncoplanar beams were used, and 3-4 full and partial coplanar and noncoplanar arcs were used in VMAT plans. One of 7 patients was not treated due to near-maximum-tolerance dose to the brainstem from the prior treatment; another patient received VMAT because of undemanding dosimetry. Five patients received 4p treatment of 25 Gy in 5 fractions (3) or 30 Gy in 10 fractions (2). Radiosurgical masks were used for immobilization. CBCT was used for initial set up. Three additional 2D X-ray images were taken to determine the intrafractional motion. A patient survey was conducted after every fraction. Results: Overall, 4p plans showed unchanged (P>0.05) or significant reductions in organs at risk (OAR) mean and max doses (P<0.05). The most clinically relevant dose improvement was a 38.4% reduction in the brainstem max dose. The 4p treatment was well tolerated by the 5 treated patients. One patient experienced moderate discomfort with positioning on the last 3/10 fractions, but tolerated the treatment without incident. The total treatment time ranged from 26 minutes with remote couch rotation to 49 minutes with manual couch rotation. The intrafractional motion was less than 1 mm for all fractions of treatment. Conclusion: We demonstrated the feasibility of delivering beam orientation and fluence optimized no-coplanar 4p treatment, with minimal intrafractional motion. The treatments were well tolerated despite longer treatment times, which can be substantially reduced with automation. Due to improved dosimetry, 4p allowed us to treat recurrent GBM without compromising target coverage yet sparing the surrounding critical structures, establishing the clinical feasibility and benefit of 4p radiation therapy.
Materials/Methods: Using the National Cancer Database from 1998-2012, we identified 2,507 patients with intracranial WHO grade I-III AE who had undergone surgical resection. Factors associated with utilization of postoperative external beam radiation therapy (RT) were evaluated using a multivariate logistic regression model. From this, a propensity score for receipt of RT was generated and incorporated into a multivariate Coxregression analysis for overall survival, excluding patients who died within 30 days of surgery or who had less than 30 days of follow-up to adjust for immortal-time bias. Results: Median follow-up was 49 months. Overall, RT utilization was administered to 45% of patients, and chemotherapy (CT) to 4.3%. Median time from diagnosis to RT initiation was 55 days. Median RT dose was 54 Gy (<54 Gy Z 20.5%, 54-59.3 Gy Z 50.3%, 59.4 Gy Z 29.2%r). On multivariable analysis (MVA) factors predictive for RT utilization were age less than 70, Charlson-Deyo comorbidity score of 0, Distance from home to treatment facility closer than 25 miles, facility volume >5 cases, tumor size >3cm, tumor grade of 3, positive surgical margin, and receiving chemotherapy. Unadjusted 5-yr overall survival was 73% (95% CI of 7076%) in irradiated patients, and 75.8% (95% CI of 73.2 e 78.4%) in patients who were observed. Factors associated with improved overall survival were younger age, lower Charlson-Deyo score, African-American race, possession of health insurance, increased residential area high school graduation rate, and tumor size 3cm. There was a non-significant trend towards increased survival in those who received post-operative radiation (HR Z 0.78 (95% C.I. 0.54-1.13), propensity adjusted HR Z 0.78 (0.531.14). We performed subset analysis based on tumor location (supratentorial vs infratentorial), extent of resection (GTR vs STR), tumor grade, and size (continuous or categorical), and were unable to identify a specific patient subset in which RT significantly improved OS. No data was available to assess the effectiveness of salvage therapy within different groups. Conclusion: This study identified factors that impact patterns of postoperative care for patients with intracranial AE. Although postoperative RT is the standard of care in pediatric ependymoma, we were unable to prove (or disprove) a significant overall survival benefit to postop RT in this large adult series regardless of stratification into potential high risk categories. This suggests that AE may behave differently than pediatric ependymoma. Author Disclosure: R. Kalash: None. S.M. Glaser: None. G.K. Balasubramani: None. J.C. Flickinger: None. S. Beriwal: None.
Abstract 2218; Table 1. Average OAR doses of the 7 patients (*P<0.05) 4p (Gy) Brainstem Chiasm Eye L Eye R Lens L Lens R Optic Nerve L Optic Nerve R
VMAT (Gy)
Mean
Max
Mean
Max
2.54* 2.98* 1.25 0.78* 0.86* 0.52* 2.80* 2.42
7.70* 5.64* 2.40 1.67 1.12 0.63* 4.01* 3.54
3.86 5.82 1.85 1.93 1.62 1.72 4.14 2.96
12.50 8.20 2.88 2.85 1.97 2.06 5.77 4.02
Author Disclosure: T.B. Kaprealian: None. A. Tran: None. V.Y. Yu: None. J. Rwigema: None. D. Nguyen: None. K. Woods: None. M. Cao: Honoraria; ViewRay. D. Low: Research Grant; Varian, Siemens. M.L. Steinberg: Travel Expenses; ViewRay. P.A. Kupelian: None. K. Sheng: Research Grant; Varian.
2219 Adult Ependymoma (AE) Patients: Practice Patterns and Overall Survival R. Kalash,1 S.M. Glaser,2 G.K. Balasubramani,3 J.C. Flickinger, Sr,2 and S. Beriwal2; 1University of Pittsburgh Medical Center, Pittsburgh, PA, 2 Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, PA, 3University of Pittsburgh School of Public Health, Department of Epidemiology, Pittsburgh, PA Purpose/Objective(s): As a rare malignancy in adults, AE represents 5% of intracranial malignancies. There is a dearth of prospective data, and many current treatment paradigms are adapted from the pediatric literature. Surgery represents the mainstay of treatment. We sought to analyze factors predictive of specific post-operative management, and the impact of such treatment on overall survival (OS) in a national data set.
2220 Single-Institution Validation of a Graded Prognostic Assessment for Evaluating Breast Cancer Patients With Brain Metastases C.H. Tai,1 A. Saraf,1 C. Grubb,1 C.C. Wu,1 A. Jani,1 M.E. Lapa,1 J.I.S. Andrews,1 H.J. Saadatmand,1 S.R. Isaacson,1 S.A. Sheth,2 G.M. McKhann,3 M.B. Sisti,2 J.N. Bruce,3 S.K. Cheng,1 E.P. Connolly,1 and T.J.C. Wang1; 1Department of Radiation Oncology, Columbia University Medical Center, New York, NY, 2Department of Neurological Surgery, Columbia University Medical Center, New York, NY, 3Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, NY Purpose/Objective(s): Breast cancer is the second most common source of brain metastases (BM). Several diagnostic-specific prognostic factors and indices have been identified as predictors of overall survival (OS) of breast cancer patients with BM: including age, Karnofsky performance score (KPS), breast tumor subtype, and number of brain metastases. Sperduto et al. established the diagnostic specific graded prognostic assessment (DS-GPA) for breast cancer which included KPS, breast cancer subtype, and age. However, the recent Subbiah et al. proposed a modified DS-GPA for primary breast cancer (breast-GPA), which included number of brain metastases. Given that the number of brain metastases has historically been associated with prognostication, we hypothesize that breastGPA is a better prognostic tool than DS-GPA.
Volume 96 Number 2S Supplement 2016 Materials/Methods: We retrospectively reviewed breast cancer patients treated with radiation for BM at Columbia University Medical Center from 1997-2015. 218 patients were identified with BM with primary breast cancer in which 127 patients had sufficient information for DS-GPA and breast-GPA scoring. Results were stratified and evaluated by DS-GPA and breast-GPA models (as per Sperduto et al. and Subbiah et al. respectively). Survival was determined using the Kaplan-Meier curves and Cox proportional hazards model. Results: Of the 127 patients, 71 patients had died, with a median overall survival of 418 days (13.7 months). The Kaplan-Meier curves for patients stratified as by DS-GPA breast classification was found to be insignificant, P Z 0.081. The same patient cohort was analyzed under the breast-GPA classification scores of 0-1.0, 1.5-2, 2.5-3, and 3.5-4, with 17, 50, 45, and 15 patients in each respective score group. Median OS for each breast-GPA score of 0-1.0, 1.5-2.0, 2.5-3.0, and 3.5-4.0, respectively, was 132, 405, 473, and 791 days. The Kaplan-Meier curves were found to be significant, P Z 0.013. Univariate Cox regression was significant for KPS (P Z 0.002), number of metastases (P Z 0.029), race (P Z 0.023), and treatment modality (P< 0.001). Conclusion: In our single institution cohort of patients with brain metastasis from primary breast cancer treated with radiation, we validated that the inclusion of number brain metastasis helps improve prognostication as per breast-GPA. Author Disclosure: C. Tai: None. A. Saraf: None. C. Grubb: None. C. Wu: None. A. Jani: None. M.E. Lapa: None. J.I. Andrews: None. H.J. Saadatmand: None. S.R. Isaacson: None. S.A. Sheth: None. G.M. McKhann: None. M.B. Sisti: None. J.N. Bruce: None. S.K. Cheng: None. E.P. Connolly: None. T.J. Wang: None.
2221 Lack of Evidence That High Dose of Radiation in Subventricle Zone (SVZ) Can Improve the Outcome in Glioblastoma (GB): Report on a Cohort of Patients S. Comas,1 S. Villa,2 J.M. Velarde,3 J. Molero,4 A. Estival,5 P. Teixidor,3 B. Guitierrez,2 Y. Luis,2 G. Perez,2 C. Panciroli,6 and C. Balana5; 1 Radiation Oncology Department. Catalan Institute of Oncology, Badalona-Barcelona, Spain, 2Catalan Institute of Oncology. HU Germans Trias, Badalona Catalonia, Spain, 3HU Germans Trias, Badalona. Catalonia, Spain, 4Catrlan Institute of Oncology. HU Germans Trias, Badalona. Catalonia, Spain, 5Catalan Institute of Oncology. HU Germans Trias, Badalona. Catalonia, Spain, 6Catalan Institute of Oncology. HU Germans Trias, Badalona Catalonia, Spain Purpose/Objective(s): Several studies have shown that high dose of radiation in SVZ in glioblastoma can improve outcome in terms of PFS and OS (Evers 2010, Chen 2013, Kut 2014). Our aim in this study has been to identify if this hypothesis is confirmed, as an independent variable Materials/Methods: One hundred six consecutive patients, 68 males and 38 females (median age 63 years), affected with GB were analyzed in a database set. All patients received radiation as part of 2 different schedules (Stupp EORTC/NCIC regime in 84 patients, and Roa regime with hypofractionated RT in 22 fragile patients). Ipsilateral, contralateral, and bilateral SVZ areas were retrospectively identified. Maximal and median radiation doses delivered, and SVZ volumes were collected. Variables as age, total radiation doses, MGMT status, KPS, and type of surgery were analyzed together with SVZ doses using univariate and multivariate Cox analysis. Results: The median survival time and progression survival time were 15 months (r 2-56) and 7 months (r 6.1-7.8), respectively. In multivariate analysis the following variables were significant for worse OS: age higher than 63 years (HR 2.65, 95% CI 1.50-4.67), biopsy alone (HR 0.26, 95% CI 0.11-0.61), unmethylated MGMT (HR 1.64, 95% CI 1.2-2.63), and 40 Gy total dose of radiation (HR 2.89, 95% CI 1.4-5.7). In the multivariate analysis the following variables were significant for worse PFS: age higher than 63 years (HR 2.30, 95% CI 1.38-3.81), biopsy alone versus total resection (HR 0.36, 95% CI 0.17-0.76), and unmethylated MGMT
Poster Viewing
E91
(HR 2.33, 95% CI 1.44-3.76). However, radiation doses higher than 43 Gy in ipsilateral, contralateral, or bilateral SVZs did not influence either PFS or OS. Conclusion: In our study high doses of radiation in SVZ areas do not influence outcome of this cohort of patients. Older patients, with poor surgery, unmethylated MGMT, and hypofractionated RT (fragile patients) showed worse outcome. Author Disclosure: S. Comas: None. S. Villa: None. J.M. Velarde: None. J. Molero: None. A. Estival: None. P. Teixidor: None. B. Guitierrez: None. Y. Luis: None. G. Perez: None. C. Panciroli: None. C. Balana: None.
2222 Hemorrhage During the Latency Period Following Volume-Staged Stereotactic Radiosurgery for Large Arteriovenous Malformations J. Chan,1 Z.A. Seymour,2 W.C. Rutledge,3 P.K. Sneed,2 and M.W. McDermott2; 1UCSF Radiation Oncology, San Francisco, CA, 2 University of California, San Francisco, San Francisco, CA, 3UCSF, San Francisco, CA Purpose/Objective(s): Hemorrhage is a significant source of morbidity and mortality during the latency period following radiosurgery and before AVM obliteration. Volume-staged stereotactic radiosurgery (VS-SRS) is an effective treatment strategy for carefully selected patients with large, unresectable AVMs but a long latency period between VS-SRS and complete obliteration is a critical limitation. We examined AVM characteristics that may predispose to hemorrhage during the latency period, which may help select patients who would benefit from more aggressive treatment paradigms. Materials/Methods: All cases of VS-SRS treatment for AVM performed from 1991-2009 at a single institution were retrospectively reviewed. Patients were followed with annual clinical and MR exams and underwent an angiogram at 3 years. Time to hemorrhage was measured from the first stage of VS-SRS using the Kaplan Meier method and subsets were compared with the log-rank test. Univariate and multivariate analyses were performed with Cox proportional hazard models. Results: Nineteen of 69 (28%) VS-SRS patients experienced at least one hemorrhage during the latency period and 9 patients (13%) died from their hemorrhages. The probability of hemorrhage in the first 30 months after SRS was 25% in the entire cohort, 40% in patients who had a prior hemorrhage within 1 year before SRS, and 20% in patients without a prior hemorrhage within 1 year before SRS. Spetzler-Martin grade 5 (SM-V) AVMs had the greatest risk of hemorrhage compared to lower grade lesions (P Z 0.0143). Univariate analysis suggested that nidus size was a risk factor for hemorrhage but not deep venous drainage nor eloquence of lesion location. Compactness of AVM and venous restrictive disease also did not correlate with risk of hemorrhage. On multivariate analysis, niduses larger than 6 cm by maximum diameter were at greater risk for hemorrhage than smaller lesions (HR 3.053, P Z 0.0351). Conclusion: In this single institution cohort of patients treated with VSSRS, nidus size greater than 6 cm was the most important risk factor for hemorrhage during the latency period. This suggests that very large AVMs require aggressive treatment. Author Disclosure: J. Chan: None. Z.A. Seymour: None. W.C. Rutledge: None. P.K. Sneed: None. M.W. McDermott: None.
2223 Hypofractionated Stereotactic Radiation Therapy Combined With Embolization Therapy in Cerebral Arteriovenous Malformations J.A. Lee,1 W.S. Yoon,2 N.K. Lee,3 Y.J. Park,3 C.Y. Kim,3 and D.S. Yang1; 1 Department of Radiation Oncology, Korea University Medical Center Guro Hospital, Seoul, South Korea, 2Department of Radiation Oncology, Korea University Medical Center Ansan Hospital, Ansan, Korea, Republic of Korea, 3Department of Radiation Oncology, Korea University Medical Center Anam Hospital, Seoul, South Korea
International Journal of Radiation Oncology Biology Physics
and normal organ sparing. The 4p plans were initially created using an inhouse beam orientation optimization program and subsequently imported into the clinical treatment planning system for dose recalculation and creation of clinically deliverable plans. A machine and human 3D model were used to eliminate undeliverable beams. In the 4p plans, 14-19 noncoplanar beams were used, and 3-4 full and partial coplanar and noncoplanar arcs were used in VMAT plans. One of 7 patients was not treated due to near-maximum-tolerance dose to the brainstem from the prior treatment; another patient received VMAT because of undemanding dosimetry. Five patients received 4p treatment of 25 Gy in 5 fractions (3) or 30 Gy in 10 fractions (2). Radiosurgical masks were used for immobilization. CBCT was used for initial set up. Three additional 2D X-ray images were taken to determine the intrafractional motion. A patient survey was conducted after every fraction. Results: Overall, 4p plans showed unchanged (P>0.05) or significant reductions in organs at risk (OAR) mean and max doses (P<0.05). The most clinically relevant dose improvement was a 38.4% reduction in the brainstem max dose. The 4p treatment was well tolerated by the 5 treated patients. One patient experienced moderate discomfort with positioning on the last 3/10 fractions, but tolerated the treatment without incident. The total treatment time ranged from 26 minutes with remote couch rotation to 49 minutes with manual couch rotation. The intrafractional motion was less than 1 mm for all fractions of treatment. Conclusion: We demonstrated the feasibility of delivering beam orientation and fluence optimized no-coplanar 4p treatment, with minimal intrafractional motion. The treatments were well tolerated despite longer treatment times, which can be substantially reduced with automation. Due to improved dosimetry, 4p allowed us to treat recurrent GBM without compromising target coverage yet sparing the surrounding critical structures, establishing the clinical feasibility and benefit of 4p radiation therapy.
Materials/Methods: Using the National Cancer Database from 1998-2012, we identified 2,507 patients with intracranial WHO grade I-III AE who had undergone surgical resection. Factors associated with utilization of postoperative external beam radiation therapy (RT) were evaluated using a multivariate logistic regression model. From this, a propensity score for receipt of RT was generated and incorporated into a multivariate Coxregression analysis for overall survival, excluding patients who died within 30 days of surgery or who had less than 30 days of follow-up to adjust for immortal-time bias. Results: Median follow-up was 49 months. Overall, RT utilization was administered to 45% of patients, and chemotherapy (CT) to 4.3%. Median time from diagnosis to RT initiation was 55 days. Median RT dose was 54 Gy (<54 Gy Z 20.5%, 54-59.3 Gy Z 50.3%, 59.4 Gy Z 29.2%r). On multivariable analysis (MVA) factors predictive for RT utilization were age less than 70, Charlson-Deyo comorbidity score of 0, Distance from home to treatment facility closer than 25 miles, facility volume >5 cases, tumor size >3cm, tumor grade of 3, positive surgical margin, and receiving chemotherapy. Unadjusted 5-yr overall survival was 73% (95% CI of 7076%) in irradiated patients, and 75.8% (95% CI of 73.2 e 78.4%) in patients who were observed. Factors associated with improved overall survival were younger age, lower Charlson-Deyo score, African-American race, possession of health insurance, increased residential area high school graduation rate, and tumor size 3cm. There was a non-significant trend towards increased survival in those who received post-operative radiation (HR Z 0.78 (95% C.I. 0.54-1.13), propensity adjusted HR Z 0.78 (0.531.14). We performed subset analysis based on tumor location (supratentorial vs infratentorial), extent of resection (GTR vs STR), tumor grade, and size (continuous or categorical), and were unable to identify a specific patient subset in which RT significantly improved OS. No data was available to assess the effectiveness of salvage therapy within different groups. Conclusion: This study identified factors that impact patterns of postoperative care for patients with intracranial AE. Although postoperative RT is the standard of care in pediatric ependymoma, we were unable to prove (or disprove) a significant overall survival benefit to postop RT in this large adult series regardless of stratification into potential high risk categories. This suggests that AE may behave differently than pediatric ependymoma. Author Disclosure: R. Kalash: None. S.M. Glaser: None. G.K. Balasubramani: None. J.C. Flickinger: None. S. Beriwal: None.
Abstract 2218; Table 1. Average OAR doses of the 7 patients (*P<0.05) 4p (Gy) Brainstem Chiasm Eye L Eye R Lens L Lens R Optic Nerve L Optic Nerve R
VMAT (Gy)
Mean
Max
Mean
Max
2.54* 2.98* 1.25 0.78* 0.86* 0.52* 2.80* 2.42
7.70* 5.64* 2.40 1.67 1.12 0.63* 4.01* 3.54
3.86 5.82 1.85 1.93 1.62 1.72 4.14 2.96
12.50 8.20 2.88 2.85 1.97 2.06 5.77 4.02
Author Disclosure: T.B. Kaprealian: None. A. Tran: None. V.Y. Yu: None. J. Rwigema: None. D. Nguyen: None. K. Woods: None. M. Cao: Honoraria; ViewRay. D. Low: Research Grant; Varian, Siemens. M.L. Steinberg: Travel Expenses; ViewRay. P.A. Kupelian: None. K. Sheng: Research Grant; Varian.
2219 Adult Ependymoma (AE) Patients: Practice Patterns and Overall Survival R. Kalash,1 S.M. Glaser,2 G.K. Balasubramani,3 J.C. Flickinger, Sr,2 and S. Beriwal2; 1University of Pittsburgh Medical Center, Pittsburgh, PA, 2 Department of Radiation Oncology, University of Pittsburgh Cancer Institute, Pittsburgh, PA, 3University of Pittsburgh School of Public Health, Department of Epidemiology, Pittsburgh, PA Purpose/Objective(s): As a rare malignancy in adults, AE represents 5% of intracranial malignancies. There is a dearth of prospective data, and many current treatment paradigms are adapted from the pediatric literature. Surgery represents the mainstay of treatment. We sought to analyze factors predictive of specific post-operative management, and the impact of such treatment on overall survival (OS) in a national data set.
2220 Single-Institution Validation of a Graded Prognostic Assessment for Evaluating Breast Cancer Patients With Brain Metastases C.H. Tai,1 A. Saraf,1 C. Grubb,1 C.C. Wu,1 A. Jani,1 M.E. Lapa,1 J.I.S. Andrews,1 H.J. Saadatmand,1 S.R. Isaacson,1 S.A. Sheth,2 G.M. McKhann,3 M.B. Sisti,2 J.N. Bruce,3 S.K. Cheng,1 E.P. Connolly,1 and T.J.C. Wang1; 1Department of Radiation Oncology, Columbia University Medical Center, New York, NY, 2Department of Neurological Surgery, Columbia University Medical Center, New York, NY, 3Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, NY Purpose/Objective(s): Breast cancer is the second most common source of brain metastases (BM). Several diagnostic-specific prognostic factors and indices have been identified as predictors of overall survival (OS) of breast cancer patients with BM: including age, Karnofsky performance score (KPS), breast tumor subtype, and number of brain metastases. Sperduto et al. established the diagnostic specific graded prognostic assessment (DS-GPA) for breast cancer which included KPS, breast cancer subtype, and age. However, the recent Subbiah et al. proposed a modified DS-GPA for primary breast cancer (breast-GPA), which included number of brain metastases. Given that the number of brain metastases has historically been associated with prognostication, we hypothesize that breastGPA is a better prognostic tool than DS-GPA.
Volume 96 Number 2S Supplement 2016 Materials/Methods: We retrospectively reviewed breast cancer patients treated with radiation for BM at Columbia University Medical Center from 1997-2015. 218 patients were identified with BM with primary breast cancer in which 127 patients had sufficient information for DS-GPA and breast-GPA scoring. Results were stratified and evaluated by DS-GPA and breast-GPA models (as per Sperduto et al. and Subbiah et al. respectively). Survival was determined using the Kaplan-Meier curves and Cox proportional hazards model. Results: Of the 127 patients, 71 patients had died, with a median overall survival of 418 days (13.7 months). The Kaplan-Meier curves for patients stratified as by DS-GPA breast classification was found to be insignificant, P Z 0.081. The same patient cohort was analyzed under the breast-GPA classification scores of 0-1.0, 1.5-2, 2.5-3, and 3.5-4, with 17, 50, 45, and 15 patients in each respective score group. Median OS for each breast-GPA score of 0-1.0, 1.5-2.0, 2.5-3.0, and 3.5-4.0, respectively, was 132, 405, 473, and 791 days. The Kaplan-Meier curves were found to be significant, P Z 0.013. Univariate Cox regression was significant for KPS (P Z 0.002), number of metastases (P Z 0.029), race (P Z 0.023), and treatment modality (P< 0.001). Conclusion: In our single institution cohort of patients with brain metastasis from primary breast cancer treated with radiation, we validated that the inclusion of number brain metastasis helps improve prognostication as per breast-GPA. Author Disclosure: C. Tai: None. A. Saraf: None. C. Grubb: None. C. Wu: None. A. Jani: None. M.E. Lapa: None. J.I. Andrews: None. H.J. Saadatmand: None. S.R. Isaacson: None. S.A. Sheth: None. G.M. McKhann: None. M.B. Sisti: None. J.N. Bruce: None. S.K. Cheng: None. E.P. Connolly: None. T.J. Wang: None.
2221 Lack of Evidence That High Dose of Radiation in Subventricle Zone (SVZ) Can Improve the Outcome in Glioblastoma (GB): Report on a Cohort of Patients S. Comas,1 S. Villa,2 J.M. Velarde,3 J. Molero,4 A. Estival,5 P. Teixidor,3 B. Guitierrez,2 Y. Luis,2 G. Perez,2 C. Panciroli,6 and C. Balana5; 1 Radiation Oncology Department. Catalan Institute of Oncology, Badalona-Barcelona, Spain, 2Catalan Institute of Oncology. HU Germans Trias, Badalona Catalonia, Spain, 3HU Germans Trias, Badalona. Catalonia, Spain, 4Catrlan Institute of Oncology. HU Germans Trias, Badalona. Catalonia, Spain, 5Catalan Institute of Oncology. HU Germans Trias, Badalona. Catalonia, Spain, 6Catalan Institute of Oncology. HU Germans Trias, Badalona Catalonia, Spain Purpose/Objective(s): Several studies have shown that high dose of radiation in SVZ in glioblastoma can improve outcome in terms of PFS and OS (Evers 2010, Chen 2013, Kut 2014). Our aim in this study has been to identify if this hypothesis is confirmed, as an independent variable Materials/Methods: One hundred six consecutive patients, 68 males and 38 females (median age 63 years), affected with GB were analyzed in a database set. All patients received radiation as part of 2 different schedules (Stupp EORTC/NCIC regime in 84 patients, and Roa regime with hypofractionated RT in 22 fragile patients). Ipsilateral, contralateral, and bilateral SVZ areas were retrospectively identified. Maximal and median radiation doses delivered, and SVZ volumes were collected. Variables as age, total radiation doses, MGMT status, KPS, and type of surgery were analyzed together with SVZ doses using univariate and multivariate Cox analysis. Results: The median survival time and progression survival time were 15 months (r 2-56) and 7 months (r 6.1-7.8), respectively. In multivariate analysis the following variables were significant for worse OS: age higher than 63 years (HR 2.65, 95% CI 1.50-4.67), biopsy alone (HR 0.26, 95% CI 0.11-0.61), unmethylated MGMT (HR 1.64, 95% CI 1.2-2.63), and 40 Gy total dose of radiation (HR 2.89, 95% CI 1.4-5.7). In the multivariate analysis the following variables were significant for worse PFS: age higher than 63 years (HR 2.30, 95% CI 1.38-3.81), biopsy alone versus total resection (HR 0.36, 95% CI 0.17-0.76), and unmethylated MGMT
Poster Viewing
E91
(HR 2.33, 95% CI 1.44-3.76). However, radiation doses higher than 43 Gy in ipsilateral, contralateral, or bilateral SVZs did not influence either PFS or OS. Conclusion: In our study high doses of radiation in SVZ areas do not influence outcome of this cohort of patients. Older patients, with poor surgery, unmethylated MGMT, and hypofractionated RT (fragile patients) showed worse outcome. Author Disclosure: S. Comas: None. S. Villa: None. J.M. Velarde: None. J. Molero: None. A. Estival: None. P. Teixidor: None. B. Guitierrez: None. Y. Luis: None. G. Perez: None. C. Panciroli: None. C. Balana: None.
2222 Hemorrhage During the Latency Period Following Volume-Staged Stereotactic Radiosurgery for Large Arteriovenous Malformations J. Chan,1 Z.A. Seymour,2 W.C. Rutledge,3 P.K. Sneed,2 and M.W. McDermott2; 1UCSF Radiation Oncology, San Francisco, CA, 2 University of California, San Francisco, San Francisco, CA, 3UCSF, San Francisco, CA Purpose/Objective(s): Hemorrhage is a significant source of morbidity and mortality during the latency period following radiosurgery and before AVM obliteration. Volume-staged stereotactic radiosurgery (VS-SRS) is an effective treatment strategy for carefully selected patients with large, unresectable AVMs but a long latency period between VS-SRS and complete obliteration is a critical limitation. We examined AVM characteristics that may predispose to hemorrhage during the latency period, which may help select patients who would benefit from more aggressive treatment paradigms. Materials/Methods: All cases of VS-SRS treatment for AVM performed from 1991-2009 at a single institution were retrospectively reviewed. Patients were followed with annual clinical and MR exams and underwent an angiogram at 3 years. Time to hemorrhage was measured from the first stage of VS-SRS using the Kaplan Meier method and subsets were compared with the log-rank test. Univariate and multivariate analyses were performed with Cox proportional hazard models. Results: Nineteen of 69 (28%) VS-SRS patients experienced at least one hemorrhage during the latency period and 9 patients (13%) died from their hemorrhages. The probability of hemorrhage in the first 30 months after SRS was 25% in the entire cohort, 40% in patients who had a prior hemorrhage within 1 year before SRS, and 20% in patients without a prior hemorrhage within 1 year before SRS. Spetzler-Martin grade 5 (SM-V) AVMs had the greatest risk of hemorrhage compared to lower grade lesions (P Z 0.0143). Univariate analysis suggested that nidus size was a risk factor for hemorrhage but not deep venous drainage nor eloquence of lesion location. Compactness of AVM and venous restrictive disease also did not correlate with risk of hemorrhage. On multivariate analysis, niduses larger than 6 cm by maximum diameter were at greater risk for hemorrhage than smaller lesions (HR 3.053, P Z 0.0351). Conclusion: In this single institution cohort of patients treated with VSSRS, nidus size greater than 6 cm was the most important risk factor for hemorrhage during the latency period. This suggests that very large AVMs require aggressive treatment. Author Disclosure: J. Chan: None. Z.A. Seymour: None. W.C. Rutledge: None. P.K. Sneed: None. M.W. McDermott: None.
2223 Hypofractionated Stereotactic Radiation Therapy Combined With Embolization Therapy in Cerebral Arteriovenous Malformations J.A. Lee,1 W.S. Yoon,2 N.K. Lee,3 Y.J. Park,3 C.Y. Kim,3 and D.S. Yang1; 1 Department of Radiation Oncology, Korea University Medical Center Guro Hospital, Seoul, South Korea, 2Department of Radiation Oncology, Korea University Medical Center Ansan Hospital, Ansan, Korea, Republic of Korea, 3Department of Radiation Oncology, Korea University Medical Center Anam Hospital, Seoul, South Korea