Concurrent Chemoradiotherapy with Temozolomide Followed by Adjuvant Temozolomide for Newly Diagnosed Glioblastoma Patients: A Retrospective Multicenter Observation Study in Korea

PURPOSE The purpose of this study was to investigate the feasibility and survival benefits of combined treatment with radiotherapy and adjuvant temozolomide (TMZ) in a Korean sample. MATERIALS AND METHODS A total of 750 Korean patients with histologically confirmed glioblastoma multiforme, who received concurrent chemoradiotherapy with TMZ (CCRT) and adjuvant TMZ from January 2006 until June 2011, were analyzed retrospectively. RESULTS After the first operation, a gross total resection (GTR), subtotal resection (STR), partial resection (PR), biopsy alone were achieved in 388 (51.7%), 159 (21.2%), 96 (12.8%), and 107 (14.3%) patients, respectively. The methylation status of O6-methylguanine-DNA methyltransferase (MGMT) was reviewed retrospectively in 217 patients. The median follow-up period was 16.3 months and the median overall survival (OS) was 17.5 months. The actuarial survival rates at the 1-, 3-, and 5-year OS were 72.1%, 21.0%, and 9.0%, respectively. The median progression-free survival (PFS) was 10.1 months, and the actuarial PFS at 1-, 3-, and 5-year PFS were 42.2%, 13.0%, and 7.8%, respectively. The patients who received GTR showed a significantly longer OS and PFS than those who received STR, PR, or biopsy alone, regardless of the methylation status of the MGMT promoter. Patients with a methylated MGMT promoter also showed a significantly longer OS and PFS than those with an unmethylated MGMT promoter. Patients who received more than six cycles of adjuvant TMZ had a longer OS and PFS than those who received six or fewer cycles. Hematologic toxicity of grade 3 or 4 was observed in 8.4% of patients during the CCRT period and in 10.2% during the adjuvant TMZ period. CONCLUSION Patients treated with CCRT followed by adjuvant TMZ had more favorable survival rates and tolerable toxicity than those who did not undergo this treatment.