Second-line chemotherapy for gastric cancer: a new issue lies ahead in global trials

Chemotherapy for gastric cancer has been advancing fairly well. It has been indicated that not only advances in first-line chemotherapy but also those in second-line chemotherapy have contributed to the prolongation of overall survival. The Arbeitsgemeinschaft Internistische Onkologie (AIO) study supports the idea that second-line chemotherapy is appropriate in patients with a good general condition. Also, the Japan Clinical Oncology Group (JCOG) integral analysis suggests that advances have been made in second-line chemotherapy. However, most recently reported studies of second-line chemotherapy have been conducted as small-scale phase II or retrospective trials. No randomized control trial to establish standard treatment has been reported. Which regimen is the most appropriate as second-line therapy must be investigated in the future. Currently, molecularly targeted agents for gastric cancer are being developed and tested in global trials. As a new issue in global trials, second-line chemotherapy has been emphasized. In recent global trials, subset analysis showed regional differences in overall survival. This was possibly associated with the regional differences in second-line chemotherapy. When developing new molecularly targeted agents for first-line chemotherapy, we cannot ignore the result that the proportion of patients in whom treatment was switched to second-line chemotherapy was high in Asia. In planning a global trial, this new issue should be sufficiently discussed.