Improvement in treatment results of glioblastoma over the last three decades and beneficial factors

Abstract

Background: The purpose of this study is to elucidate the trend of glioblastoma outcome and scrutinize the factors contributing to better outcome over three decades.

Methods: Survival time and the influencing factors were retrospectively analyzed in 223 newly diagnosed primary glioblastoma patients during 1980-2010. Appraised factors included age, sex, tumor site, year of surgery, extent of resections, use of surgery supporting system, Karnofsky Performance Status (KPS), chemotherapy, conventional external beam radiotherapy (EBRT), and CyberKnife stereotactic radiotherapy (CK-SRT) use.

Results: The median survival time (MST) in all patients was 13.6 months. The MSTs for 4 periods were 9.8 (1980-1990), 13.7 (1991-2000), 12.9 (2001-2005), and 15.8 months (2006-2010), respectively (p=0.0047). Total resection, subtotal resection, partial resection, and biopsy had MSTs of 31.8, 13.9, 11.4, and 7.0 months, respectively (p<0.0001). Regarding chemotherapy, MSTs of the temozolomide base group and nimustine hydrochloride (ACNU) base group were 16.9 and 14.6 months, respectively, whereas the MST of patients without chemotherapy was only 9.8 months (p<0.0001). The MSTs for 40-Gy EBRT plus CK-SRT and 60-Gy EBRT were 19.1 and 10.7 months, respectively (p<0.0001). But in sub-selected patients, treated during 2001-2010, whose resection rate was total resection or subtotal resection, EBRT was completed and postoperative KPS was greater than or equal to 70, the MST with and without CK-SRT was 26.6 and 18.3 months, respectively (p=0.1529). According to the Cox proportional hazards model, degree of resection, KPS, ACNU use, temozolomide use, bevacizumab use, EBRT dose, and CK-SRT use were good prognostic factors. Use of neuronavigation and use of intraoperative magnetic resonance imaging were related to higher resection rate, but not determined as prognostic factors.

Conclusions: We observed a gradual improvement in glioblastoma outcome, presumably because of improvements in therapeutic modalities for surgery, anticancer agents, and radiation, but the efficacy of CK-SRT remains unclear.

Keywords: CyberKnife; chemotherapy; extent of resection; glioblastoma; outcome.