Survival Benefit of Maximal Resection for Glioblastoma Reoperation in the Temozolomide Era: A Meta-Analysis

BACKGROUND: Although reoperation likely confers survival benefit for glioblastoma, whether the extent of resection (EOR) of the reoperation affects survival outcome has yet to be thoroughly evaluated in the current temozolomide (TMZ) era. The aim of this meta-analysis was to pool the current literature and evaluate the prognostic significance of reoperation EOR for glioblastoma recurrence in the current TMZ era. METHODS: Searches of 7 electronic databases from inception to January 2019 were conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. There were 1203 articles identified for screening. Prognostic hazard ratios (HRs) for overall survival (OS) derived from multivariate regression analysis were analyzed using meta-analysis of proportions. RESULTS: Nine individual studies satisfied all selection criteria, describing survival in 1507 patients with glioblastoma, including 1335 reoperations for recurrence (89%). When studies incorporated the EOR of index surgery into their analysis, maximal resection at reoperation was significantly prognostic for longer OS (HR, 0.59; 95% confidence interval [CI], 0.43-0.79; I-2 = 0%; P heterogeneity <0.01). When studies did not incorporate the EOR of index surgery into their analysis, maximal resection remained significantly prognostic for longer OS at reoperation (HR, 0.53; 95% CI, 0.45-0.64; I-2 = 5.2%; P heterogeneity <0.01). Based on EOR, radiographic gross total resection (GTR) was the most prognostic EOR definition at reoperation (HR, 0.52; 95% CI, 0.44-0.61; I-2 = 0%; P heterogeneity <0.01). CONCLUSIONS: In the current TMZ era, when reoperation is feasible for recurrent glioblastoma, maximal safe resection appears to confer a significant OS benefit based on the current literature. This benefit is most pronounced with radiographic GTR, and likely irrespective of EOR at index surgery.