2031 Background: Grade II glioma patients with subtotal resection (STR) or age ≥ 40 are considered high risk. RTOG 9802 demonstrated that for these high-risk patients, chemotherapy and radiation therapy improved overall survival (OS) compared to radiation alone. The purpose of this study is to compare the OS of high risk, grade II glioma patients treated with adjuvant chemotherapy alone (CA) to chemotherapy and radiation therapy (CRT). Methods: Using the National Cancer Data Base (NCDB), high risk (age ≥ 40 or STR) grade II glioma patients with oligodendroglioma, astrocytoma, or mixed tumors were identified. Patients receiving CA were compared to patients receiving CRT. Univariate and multivariable analyses (MVA) were performed. Propensity score (PS) matching was utilized to account for difference in patient characteristics. Kaplan Meier statistics were utilized to compare OS. Results: 1054 high risk, grade II glioma patients were identified, 47.1% receiving CA and 52.9% receiving CRT. Median follow up time was 55.1 months. Patients treated with CA were statistically more likely (all p < 0.05) to be oligodendroglioma histology (65.5% vs. 34.2%), 1p/19 co-deleted (22.8% vs. 7.5%), younger median age (47 vs. 48 years) and treated at an academic program (65.2% vs. 50.3%). MVA demonstrated treatment type was not a significant predictor for OS (p = 0.125), while tumor size > 6cm, astrocytoma histology, and older age were predictors for worse survival (all p < 0.05). Utilizing 1:1 PS matching, with 662 total patients, OS was statistically similar (p = 0.919) for CA and CRT at 5 years (69.1% vs. 68.5%, respectively) and 7 years (55.5% vs. 60.0%, respectively). Conclusions: In this retrospective analysis of the NCDB, long term OS for high-risk, grade II glioma patients treated with CA appears similar to CRT. These findings are hypothesis generating, with the standard of care still remaining CRT as established by RTOG 9802. Prospective clinical trials comparing CA and CRT are warranted.
RE: Adjuvant Radiation Therapy and Chemotherapy in Merkel Cell Carcinoma: Survival Analyses of 6908 Cases From the National Cancer Data Base