(P125) Glioblastoma Multiforme Outcome Comparison Between Pediatrics and Adults: Is There a Difference?

Dayssy A. Diaz, MD, Duran Mitchell, Isildinha Reis, PhD, Joseph Panoff, MD; Department of Radiation Oncology, Division of Biostatistics, Department of Public Health Sciences, University of Miami

PURPOSE: There is a paucity of data regarding the clinical outcome of glioblastoma multiforme (GBM) in the pediatric population. Previous data suggest that there is a difference in overall survival (OS) between pediatric patients and adult patients with GBMs; however, there have been no direct comparisons in the literature. We compared pediatric and adult GBM outcome measures using the Surveillance, Epidemiology, and End Results (SEER) database, a program of the National Cancer Institute that collects cancer incidence and survival data from approximately 28% of the US population.

MATERIALS AND METHODS: Patients with pathologically confirmed grade 4 gliomas diagnosed between 1980 and 2011 were included in this analysis. Patients aged older than 60 years were excluded from the analysis. Pediatric cases were classified as those aged ≤21 years. Cause-specific survival (CSS) and overall survival (OS) were estimated by Kaplan-Meier (product-limit) method. Cox proportional hazards analyses were performed, evaluating potential predictors of CSS and OS.

RESULTS: There were 6,351 patients available for comparison; 6,099 patients were adults, and 252 patients were pediatric. The median age for the pediatric patients was 13 years, and the median age for the adults was 52 years. The OS time was the same as the CSS for pediatric patients (16 mo). The same observation was seen for adults (12 mo). Pediatric patients had a significantly better OS (P < .001) and CSS (P < .0001) when compared with adults. The 3-year OS was 23.4% for pediatrics vs 11.8% for adults, and the 3-year CSS was 24.3% for pediatrics vs 12.9% for adults. These results persisted when stratified by decade of diagnosis (1980s: P = .0008; 1990s: P = .0229; and 2000s: P < .0001). Univariate analysis indicated female sex (P = .03), use of radiation (P < .0001), surgical resection (P < .0001), age (P < .0001), recent year of diagnosis (P < .0001), and pediatric patients (P < .0001) to be significant predictors of improved OS. Multivariate analysis demonstrated that pediatric status, use of surgery, use of radiation, and recent decade of diagnosis were significant predictors of OS and CSS (P < .0001 for all variables). Race was found to be a significant predictor of CSS (P = .0132) but not of OS (P = .667).

CONCLUSION: This is the first report to directly compare pediatric and adult patients with GBM. Pediatric patients had significantly superior OS and CSS when compared with adults, and these differences remained significant over time and on multivariate analysis. The underlying cause of these survival differences between pediatrics and adults requires exploration, with attention to molecular biological tumor differences.

Proceedings of the 97th Annual Meeting of the American Radium Society - americanradiumsociety.org