Overview of chemoradiation clinical trials for locally advanced non-small cell lung cancer in Japan

The standard of care for unresectable stage III non-small cell lung cancer (NSCLC) is combined-modality therapy with both chemotherapy and thoracic radiation therapy (TRT). A phase III trial by the West Japan Lung Cancer Group revealed that the combination of mitomycin, vindesine, and cisplatin (MVP) with concurrent TRT yielded a median survival time of 16.6 months and a 5-year survival rate of 16% in patients with unresectable stage III NSCLC. Although evidence indicates that concurrent chemotherapy and TRT (chemoradiation) increases survival to a moderately greater extent than sequential therapeutic approaches, the optimal strategies for such concurrent treatment remain to be defined, and differ between full-dose systemic and low-dose radio-enhancing protocols. Two phase III trials have been initiated in Japan to address these issues and they have recently reported preliminary data. Early results of the Okayama Lung Cancer Study Group (OLCSG) trial, comparing chemoradiation based on divided docetaxel and cisplatin chemotherapy with MVP-based chemoradiation, have been reported. The West Japan Oncology Group (WJOG) is comparing the efficacy and toxicity of TRT and concurrent chemotherapy with either carboplatin-paclitaxel or carboplatin-irinotecan, followed by full-dose consolidation chemotherapy, with the efficacy and toxicity of MVP-based chemoradiation. Several phase I/II studies to test the optimal use of new agents such as S-1 (an oral anticancer drug combining tegafur, 5-chloro-2, 4-dihydroxypyridine, and potassium oxonate) and gefitinib (an inhibitor of the tyrosine kinase activity of the epidermal growth factor receptor) are also ongoing. In addition, radiation dose intensification with three-dimensional planning approaches is currently under evaluation. A phase I clinical trial by WJOG to establish, prospectively, the maximum tolerated dose of three-dimensional hyperfractionated radiotherapy with concurrent weekly chemotherapy (carboplatin-paclitaxel) is thus currently under way. This overview of ongoing trials highlights new directions in the treatment of locally advanced NSCLC.