Supramaximal resection: A systematic review of its safety, efficacy and feasibility in glioblastoma.

The philosophy of 'supramaximal resection' (SMR) beyond the T1-enhanced margin holds some potential in glioblastoma surgery, but the quality of available literature has not been elucidated. A systematic review of published studies of SMR in glioblastoma surgery was performed. Articles were sought in MEDLINE, EMBASE, Scopus and Cochrane Central Register for Clinical Trials. The search items were grouped into three themes; supramaximal resection, glioblastoma and outcomes. Cases were included wherein the initial extent of resection was described as exceeding gross total resection, that is to say, beyond the area of T1-enhancement on MRI. Only newly diagnosed glioblastoma was considered. Articles containing primary patient data, including outcome data, were included; reviews, editorials, descriptive articles and systematic reviews were excluded. Subsequently, 1123 unique articles were initially retrieved. After screening article titles and abstracts for relevance to SMR in glioblastoma, seven articles remained, and were all included post-full text review. No randomized controlled trials were discovered. Almost all studies were of Level 4 quality, according to Oxford Center for Evidence-Based Medicine guidelines. The included articles yielded a total of 2019 surgically treated glioblastoma patients, 13.5% of whom underwent SMR. Preliminary results suggest SMR of glioblastoma positively impacts overall and progression free survival. However, the contemporaneous literature supporting glioblastoma SMR is of low quality, with neither anatomical nor radiographic definitional consensus for what constitutes SMR. Prospective studies of larger pooled populations with standardized technical, radiological and outcome measures in designated centers would help minimize bias and validate SMR in appropriately selected glioblastoma patients. Crown