Prognostic role of chemotherapy, radiotherapy dose, and extent of surgical resection in adult medulloblastoma

Purpose: Adult medulloblastoma is rare, and management is extrapolated from pediatric cases. This investigation evaluated the prognostic role of chemotherapy (and sequencing thereof), the degree of resection, and craniospinal irradiation (CSI) dose. Methods: The National Cancer Database was queried for adult (age ≥18) medulloblastoma. Resection was coded as gross (GTR) or subtotal resection (STR) or biopsy only; concurrent chemoradiotherapy (CRT) was defined as receipt within 14 days of each other. Statistics included Kaplan-Meier overall survival (OS) analysis and Cox proportional hazards modeling. Results: Of 1144 patients, 613 had coded surgical information; 242 (39%) did not undergo surgery, 277 (45%) underwent STR, and 94 (15%) had GTR. A total of 428 (37.4%) did not receive chemotherapy, 348 (30.4%) received sequential CRT, and 368 (32.2%) underwent concurrent CRT. Of the 711 patients with CSI dose information, 202 (28.4%) received 23–30 Gy CSI and 509 (71.6%) patients received 30–36 Gy. Median follow-up was 56.5 months. Extent of resection did not correlate with 10-year OS (74.2% biopsy only, 72.7% STR, 82.2% GTR, p > 0.05 all comparisons) or on Cox multivariate analysis. Chemotherapy was associated with higher OS (65.6% vs. 51.2%, p = 0.035) and a trend towards significance on multivariate assessment (p = 0.082). Sequencing of chemotherapy and CSI dose were not associated with OS (p > 0.05 for both). Conclusions: Although causation cannot be implied, neither the extent of resection nor CSI dose associated with OS in adult medulloblastoma. Chemotherapy could have utility in higher-risk patients; concurrent administration may not be beneficial, especially given therapy-induced neuro-cognitive sequelae.