Impact of extent of resection and recurrent surgery on clinical outcome and overall survival in a consecutive series of 170 patients for glioblastoma in intraoperative high field magnetic resonance imaging

BACKGROUND: In patients with a glioblastoma (GBM), few unselected data exists using actual standard adjuvant treatment and contemporary surgical techniques like iMRI. Aim of study is to assess impact of EoR and recurrent surgery on survival and outcome. METHODS: We assessed a consecutive unselected series of 170 surgeries for GBM (2008-2014) applying intraoperative MRI (iMRI). All patients received adjuvant radio-chemo-therapy. Overall-survival (OS), progression free survival (PFS), complications and new permanent neurological deficits (nPND) were assessed. Uni- and multivariate-cox-regression-models were calculated. RESULTS: Mean follow-up was 40mo. GTR was intended in 82% and achieved in 77% of these cases. A nPND was found in 7% of patients. In multivariate cox-regression, GTR (HR:0.6, P<0.024) and absence of MGMT methylation (HR:1.6, P<0.042) was significantly associated with PFS. We found no difference in PFS after primary surgery and recurrent surgery. Concerning OS, in multivariate assessment an un-methylated MGMT-promotor (HR2.0, P<0.01) and presence of a complication (HR1.7, P<0.06) were negative prognosticators. Only GTR was significantly beneficial for OS (HR0.4, P<0.028) compared to a failed GTR and a STR. Repeated surgery for recurrent disease was positively associated with OS (HR0.6, P<0.06). CONCLUSIONS: Surgery in a contemporary setup using iMRI, brain mapping and modern adjuvant treatment, has a higher OS and lower complication rates as previously published. A maximum but safe resection should be the goal of surgery since a perioperative complication significantly decreases OS. Recurrent surgery has a beneficial effect on OS without an increase of complications.