However, the meta-analysis included of patients with prognostically more favorable lower-grade gliomas. The present study showed that glioblastoma patients initially treated with a combined treatment of RT plus TMZ had significantly longer survival than historical controls, with a median survival benefit of 4.0 months. The survival advantage of the combined treatment lasted for at least 3 years. Multivariate analysis showed that TMZ therapy was the second most significant factor influencing survival after the extent of surgery. AbMole Corosolic-acid Although the present study is retrospective and took place in a single institution, to the best of our knowledge, this is the first report investigating the effect of combined therapy with RT and TMZ on Japanese patients with newly diagnosed glioblastoma. Our results on the survival of TMZ-treated patients were in line with the results of the randomized phase III trial by the EORTC and NCIC. First, the number of TMZ-treated patients who received GTR was smaller in the present study than in the Stupp trial. This difference could be a negative bias for survival in the present study because the extent of surgery is one of the most significant prognostic factors in glioblastoma, as most previous studies have described. Second, the incidence of hematologic toxicity of grade 3 or higher was greater in the present study than in the Stupp trial during the concomitant RT and TMZ periods. Third, adjuvant TMZ was continued as long as it was tolerable in the present study, while a maximum of 6 cycles were administered in the Stupp trial. Interestingly, in contrast with the concomitant period, the incidence of hematologic toxicity of grade 3 or higher was lower in the present study than the Stupp trial during the adjuvant period. As a result, the average number of adjuvant TMZ cycles administered in the present study was 7. The number of patients completing 6 cycles of TMZ treatment was greater in our study than the Stupp trial. It is difficult to conclude how all of the differences described above AbMole Pamidronate disodium pentahydrate actually affected the clinical outcome. However, the results of the present study indicate that the addition of TMZ to RT is beneficial for the survival for Japanese patients with newly diagnosed glioblastoma. In their study, 5 techniques, MS-PCR, pyrosequencing, immunohistochemistry, methylation-sensitive high-resolution melting and high-throughput quantitative methylation assay, were investigated. As a result, pyrosequencing, MS-PCR and immunohistochemistry had significant predictive value for overall survival. In the present study, we selected immunohistochemical method to assess MGMT expression status because the amount of pathological samples was insufficient for performing MS-PCR.