Comparative epidemiology of gliosarcoma and glioblastoma and the impact of Race on overall survival: A systematic literature review

Objective: Gliosarcoma (GSM) is a rare subtype of glioblastoma (GBM) that accounts for approximately four percent of high-grade gliomas. There is scarce epidemiological data on patients with GSM as a distinct subgroup of GBM. Methods: A systematic literature review was performed of peer-reviewed databases using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines to evaluate the impact of race and ethnicity on survival in patients with GSM compared to patients with GBM. Results: Following initial abstract screening, a total of 138 articles pertaining to GSM and 275 pertaining to GBM met criteria for full-text review, with 5 and 27 articles included in the final analysis for GSM and GBM, respectively. The majority of patients in both cohorts were non-Hispanic Whites, representing 85.6 % of total GSM patients and 87.7 % of GBM patients analyzed. Two GSM studies stratified survival by race, with one reporting the longest median survival for the Hispanic population of 10.6 months and the shortest median survival for the Asian population of 9 months. Among the GBM studies analyzed, the majority of studies reported shorter survival and higher risk of mortality among White Non-Hispanics compared to non-White patients; and of the 15 studies which reported data for the Asian population, 12 studies reported this race category to have the longest survival compared to all other races studied. Younger age, female sex, MGMT promoter methylation status, and adjuvant chemoradiation therapy were associated with improved survival in both GSM and GBM cohorts, although these were not further stratified by race. Conclusion: GSM portends a similarly poor prognosis to other GBM subtypes; however, few studies exist which have examined factors associated with differences in survival between these histologic variants. This review of the literature suggests there is a possible association between race and survival for patients with GBM, however data supporting this conclusion for patients with GSM is lacking. These findings suggest that GSM is a distinct disease from other GBM subtypes, with epidemiologic differences that should be further explored.