RT-36 * ONCOLOGIC OUTCOME OF HISPANIC PATIENTS WITH GLIOBLASTOMA TREATED WITH RADIOTHERAPY

Abstract

BACKGROUND: Underutilization of radiotherapy in minorities with glioblastoma (GBM) has been reported. We sought to investigate whether patients of Hispanic descent with GBM had different presentation, treatment, oncologic outcomes compared to Caucasian patients. METHODS: We reviewed all patients with GBM treated with radiotherapy at Columbia University Medical Center from 1998 to 2013. Variables analyzed included age, gender, race, Karnofsky performance status, molecular markers, extent of resection, and radiotherapy scheme. RESULTS: From 1998 to 2013, 444 Caucasian and Hispanic patients with GBM were treated with radiotherapy at our institution. Baseline characteristics (age, gender, KPS) were similar among the two groups (Hispanic vs. Caucasian), as was extent of resection. For example, there were 85 patients of Hispanic descent with a median age of 58 (range 4-91) years, 51 (60%) were men, and median KPS was 80 (range 50-100). In Caucasians cohort (N = 361), the median age was 61 (range 7-87), 208 (58%) were men, and median KPS was 80 (range 30-100). Among the Hispanic patients, 85.5% had gross total or subtotal resection and 14.5% biopsy whereas in Caucasians, 83.2% had gross total or subtotal resection and 16.8% biopsy only. Hispanic and Caucasian patients had similar rates of MGMT methylation (38.5% vs. 42.9%), IDH-1 mutation (5.9% vs. 7.9%), and positive EGFR immunohistochemical staining (78.9% vs. 74.4%). Similar rates of Hispanic and Caucasian patients received intensity-modulated radiotherapy (50.0% vs. 52.4%) and three-dimensional conformal radiotherapy (35.4% vs. 45.4%); whereas more Hispanic patients received two-dimensional radiotherapy (14.5% vs. 2.2%). However, median survival was not statistically different among Hispanics than Caucasians: 287 vs. 388 days (HR: 1.147; 95%CI: 0.863-1.524; p = 0.346). CONCLUSIONS: We found that Hispanic patients with GBM had a trend toward worse but not statistically different overall survival than Caucasian patients having similar baseline characteristics, types of surgery, radiotherapy, and molecular markers.