Prognostic Value of Tumor Volume in Glioblastoma Patients: Size Also Matters for Patients with Incomplete Resection

Incomplete resection of glioblastoma is discussed controversially in the era of combined radiochemotherapy. The aim of this study was to analyze the benefit of subtotal tumor resection for glioblastoma patients as this was recently questioned in the era of radiochemotherapy. Overall, 209 patients undergoing surgery for newly diagnosed WHO grade IV gliomas were retrospectively analyzed, and pre- and postoperative tumor volumes were manually segmented (cm(3)). Survival analyses were performed, including prognostic factors such as age, Karnofsky performance score (KPS), O-6-methylguanine-DNA-methyltransferase (MGMT) promoter methylation status, and adjuvant treatment regimen. Pre- and postoperative tumor volume is significantly associated with pre- and postoperative KPS, as well as age (p < 0.001). Postoperative tumor volume remained a significant prognostic factor in a multivariate analysis, independent of other prognostic factors (hazard ratio 1.0365, 95% confidence interval 1.0235-1.0497, p < 0.001). In the era of molecularly-driven radiochemotherapy, glioblastoma surgery remains a major prognostic factor. Even in situations in which a gross total resection cannot be achieved, maximum safe reduction of tumor burden should be attempted.