The Association of Subventricular Zone Involvement at Recurrence with Survival after Repeat Surgery in Patients with Recurrent Glioblastoma

Surgical resection is identified as an important prognostic factor for survival in patients undergoing initial resection of glioblastoma (GBM). However, in patients with tumor recurrence, the benefits of repeat surgery remain unclear. Recent reports have stated that the association between initial surgery for GBM and subventricular zone (SVZ) influences survival. The current study examined the relationship of SVZ involvement in recurrent GBM to survival time after reoperation. We conducted a retrospective review of 61 consecutive patients who had undergone repeat surgery for recurrent GBM at our institution between 1997 and 2010. Survival after repeat surgery were compared between patients with (n = 29) and without (n = 32) SVZ involvement at recurrence using univariate analysis with known prognostic factors, including sex, age, Karnofsky Performance Status (KPS) score at recurrence, recurrent tumor size, initial SVZ involvement, and adjuvant therapy after repeat surgery, as variables. All 26 SVZ-positive tumors at initial diagnosis recurred as SVZ-positive tumors, while 32 of 35 SVZ-negative tumors at initial diagnosis remained SVZ-negative at recurrence; the remaining three were SVZ-positive at recurrence. Survival after repeat surgery was decreased in patients with recurrent GBM involving the SVZ at recurrence (p = 0.022). No other prognostic factors for survival after repeat surgery were identified in this study. This finding may have prognostic and therapeutic significance.