E.P. Connolly,1 and T.J.C. Wang1,4; 1Department of Radiation Oncology,. Columbia University Medical Center, New York, NY, 2Department of. Radiation ...
Poster Viewing E107
Volume 96 Number 2S Supplement 2016 Conclusion: In this preliminary study, radiomics approach combined with patients’ demographics and clinical parameters are promising (even MGMT status was not available) for survival analysis and prediction in GBM patients treated with CRT. To achieve more accurate predictions, advanced machine learning models should be considered. Author Disclosure: H.H. Zhang: Research Grant; Varian Medical Systems. J.K. Molitoris: None. S. Tan: None. I. Giacomelli: None. D. Scartoni: None. C. Gzell: None. N. Bhooshan: None. W. Choi: None. W. Lu: None. W.D. D’Souza: None. M.P. Mehta: None.
2261 Risk Factors Associated With Interval Time Between Breast Cancer Diagnosis and Development of Brain Metastasis A. Saraf,1 C. Grubb,1 C.H. Tai,1 C.C. Wu,1 A. Jani,1 H.J. Saadatmand,1 M.E. Lapa,1 J.I.S. Andrews,1 S.D. Vanderkelen,2 S.R. Isaacson,1 S.A. Sheth,3 G.M. McKhann,4 M.B. Sisti,3 J.N. Bruce,4 S.K. Cheng,1 E.P. Connolly,1 and T.J.C. Wang1,4; 1Department of Radiation Oncology, Columbia University Medical Center, New York, NY, 2Department of Radiation Oncology, Columbia University, New York, NY, 3Department of Neurological Surgery, Columbia University Medical Center, New York, NY, 4 Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, NY Purpose/Objective(s): Breast cancer (BC) is a common cause of brain metastases (BM) associated with poor prognosis. At this time, the standard work up for BC does not include radiographic work up to rule out BM. We hypothesize that risk factors associated with BC may be associated with a shorter time interval for the development of BM in patients with primary breast cancer. Our goal is to identify potential BC risk factors associated with increased risk for BM. Materials/Methods: We retrospectively reviewed all BC patients with BM treated with radiation therapy at Columbia University Medical Center from 1997 to 2015. Interval time (IT) to developing BM was defined as pathological diagnosis of BC to radiographic diagnosis of BM. Kaplan-Meier (KM) curves were used to analyze the timing for developing of BM. Patients were stratified by breast cancer subtype (Her2, Luminal A/B, and triple negative) and initial BC staging. For KM analysis with BC staging, patients with stage IV disease with initial presentation of BM were excluded from the analysis. Cox proportion hazard models were used to evaluate the associated BC risk factors for development BM. Results: A cohort of 128 BC patients with BM had known BC subtype and was used in this cohort. The median IT for the entire cohort was 46 months. KM curves showed a significant difference in median IT for Her2 subtype (57 months), Luminal A/B (50 months), and triple negative (28 months) with P Z 0.005. When stratified by initial tumor staging, KM curves showed a significant difference in IT for Stage I (70 months), II (54 months), III (23 months), and IV (24 months) with P Z 0.001. Univariate analysis was performed to determine factors associated with shorter interval to the development of brain metastasis. Those included BC subtype, initial BC staging, no surgical intervention for initial BC, positive nodal status, late age of first birth, history of hormone replacement therapy (HRT), and ethnicity. Conclusion: BC subtype and initial BC staging is associated with IT to the development of BM. Additional factors including absence of primary BC surgical intervention, positive nodal status, late age of first birth, HRT and ethnicity might be related to shorter IT to BM. These results support the notion that there may be a subset of breast cancer patients in which brain MRI for staging work up can be beneficial. Author Disclosure: A. Saraf: None. C. Grubb: None. C. Tai: None. C. Wu: None. A. Jani: None. H.J. Saadatmand: None. M.E. Lapa: None. J.I. Andrews: None. S.D. Vanderkelen: 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.
2262 Hypofractionated Versus Standard Radiation Therapy in Combination With Concurrent Chemotherapy for Elderly Glioblastoma Patients: A Review of the National Cancer Data Base J. Huang,1 P. Samson,2 S.M. Perkins,1 T.A. DeWees,3 and C.G. Robinson1; 1 Washington University in St. Louis, Department of Radiation Oncology, St. Louis, MO, 2Washington University in St. Louis, Department of Surgery, St. Louis, MO, 3Washington University School of Medicine, St. Louis, MO Purpose/Objective(s): To evaluate the effectiveness of two radiation therapies (RT) fractionation schedules when administered with concurrent chemotherapy for elderly patients with newly diagnosed glioblastoma (GBM). Materials/Methods: Elderly patients (age 60) with supratentorial and nonmetastatic GBM who underwent surgery followed by adjuvant RT of 1.8-60 Gy in combination with concurrent chemotherapy during 20102012 were identified from the National Cancer Data Base (NCDB). Concurrent chemotherapy (either single-agent or multi-agent) was specified to be within 14 days from the start of RT. Hypofractionated RT (HFRT) was defined as those who received 45 Gy with fraction size between 2.5-4 Gy. Standard-fractionated RT (SFRT) was defined as those who completed at least 45 Gy (with any fraction size) or 45 Gy but with fraction size between 1.8-2 Gy. Prognostic factors affecting OS were evaluated using Kaplan Meier method and Cox proportional hazards. Propensity score matching (PSM) was performed to adjust for potential selection bias between SFRT and HFRT groups using all available variables. Conditional inference tree regression analysis (CITRA) was performed to identify subsets of patients with comparable OS when treated with either RT schedule. Results: A total of 5265 evaluable patients were identified: 5048 received SFRT; 217 received HFRT. During the study period, HFRT use remained consistently low at < 5% per year. Older age, higher Charlson/Deyo comorbidity index (CDCI), Medicare insurance, and subtotal resection (STR) were associated with HFRT use. Median follow-up time was 10.3 months. HFRT had inferior OS compared to SFRT (median: 6.4 vs 11.2 months, P70 with CDCI >0 (median: 6.9 vs 6.7 months, P Z 0.89); age >70 with CDCI of 0 and gross-total resection (median: 10.7 vs 10.6 months, P Z 0.37). Conclusion: HFRT is associated with worse OS than SFRT when administered with concurrent chemotherapy for elderly GBM patients in routine clinical practice. Age, CDCI, and surgical extent may be factors that can be used to guide selection of HFRT. Author Disclosure: J. Huang: Travel Expenses; Viewray. P. Samson: None. S.M. Perkins: None. T.A. DeWees: None. C.G. Robinson: Research Grant; Elekta. Advisory Board; Radialogica. Travel expenses and speaker’s bureau; Varian Medical Systems. Stock Options; Radialogica.
2263 Feasibility of Simultaneous Integrated Boost (SIB) to Gross Disease in Spine Radiosurgery O. Padilla,1 T. Botticello,2 B. Winey,3 A. Niemierko,2 J. Shin,4 and K.S. Oh3; 1Tufts University School of Medicine, Boston, MA, 2 Massachusetts General Hospital, Boston, MA, 3Massachusetts General Hospital, Harvard Medical School, Boston, MA, 4Harvard Medical School, Boston, MA
