Objective  To assess the prognostic factors of World Health Organization (WHO) grade Ⅱ gliomas.

  Methods  A total of 146 patients diagnosed with WHO grade Ⅱ gliomas were treated at Jiangxi Province Tumor Hospital between June 1997 and April 2015, including 90 gross total resections (GTRs) and 56 partial resections. According to the 2007 WHO grading system of gliomas, there were 96 astrocytomas, 30 oligodendrogliomas, and 20 oligoastrocytomas.

  Results  The median follow- up time was 88 months. Five- year overall survival (OS) and progression-free survival (PFS) rates were 75.7% and 60.0%, respectively, and 10-year OS and PFS rates were 57.4% and 37.8%, respectively. Univariate analysis of OS revealed statistically significant differences in age, sex, subventricular zone (SVZ) invasion, peritumoral edema, residual tumor volume, preoperative tumor size and numbers, and the extent of resection (P < 0.05). Compared with astrocytoma patients, oligodendroglioma patients had better OS and PFS (P=0.040 and 0.049, respectively). Among those factors, sex, SVZ invasion, residual tumor volume, preoperative tumor numbers, and the extent of resection were likewise significant for PFS (P < 0.05). Multivariate analysis revealed that the extent of resection, SVZ invasion, and peritumoral edema were independent prognostic factors for OS (P < 0.05) and the extent of resection and tumor numbers were independent prognostic factors for PFS (P < 0.05). Sixty patients developed recurrences, including 53 tumor bed failures and 7 intracranial disseminations.

  Conclusions  The extent of resection, SVZ invasion and peritumoral edema may be independent prognostic factors for OS in low-grade gliomas. Postoperative radiotherapy would improve PFS for patients who underwent GTRs. The major pattern of failure was tumor bed recurrence.