Effects of Temozolomide and Radiotherapy on Brain Metastatic Tumor: A Systematic Review and Meta-Analysis

OBJECTIVE: To systematically evaluate safety and efficacy of temozolomide plus radiotherapy in the treatment of brain metastasis. METHODS: Literature was searched in the following databases: Cochrane Controlled Trials Register (CENTRAL), PubMed (1994-2015.10), CBM (1978-2015.10), CNKI (1994-2015.10), VIP (1994-2015.10), and WANFANG (1994-2015.10). Randomized clinical trials (RCTs) of temozolomide plus radiotherapy in comparison with radiotherapy alone were included in this review and meta-analysis. The quality of included literatures was assessed by the international Cochrane collaboration method, and meta-analysis was performed using RevMan 5.0 software. RESULTS: Total 19 publications of RCTs were included, and there was no allocation concealment or blinding in any of them. Six of the 19 were multicenter RCTs. Overall response rate (ORR) was in favor of radiotherapy plus temozolomide (risk ratio [RR] [1.35, 95% CI: 1.23-1.47). Subgroup analysis of nonesmall cell lung cancer (NSCLC) metastasis brain tumor also showed that ORR was in favor of radiotherapy plus temozolomide (RR [1.38; 95% CI: 1.17-1.63). Progression-free survival (PFS) or overall survival rate, however, was not significantly different between the 2 treatment groups. In addition, incidence of side effect was significantly higher in the group of radiotherapy plus temozolomide than that of radiotherapy alone (HR [2.03, 95% CI: 1.56-2.64). CONCLUSION: Addition of temozolomide to radiotherapy could increase ORR in brain metastatic tumors. However, it did not significantly improve PFS or OS in the patients with brain metastases but increased risk of drug-related toxicity.