Perioperative chemotherapy for locally advanced gastric cancer in Japan: current and future perspectives.

The standard treatment for locally advanced gastric cancer differs across the world. In western countries, perioperative chemotherapy or postoperative adjuvant chemoradiotherapy are the preferred treatment options, whereas in Asia, D2 gastrectomy followed by postoperative adjuvant chemotherapy is standard. In Japan, adjuvant chemotherapy with S-1 is the standard treatment for pStage II gastric cancer, whereas adjuvant chemotherapy with a doublet regimen is preferred for pStage III gastric cancer. The efficacy of preoperative neoadjuvant chemotherapy using S-1 plus cisplatin, has been investigated in selected patients with expected poor survival outcomes. To expand the indications for neoadjuvant chemotherapy, a clinical trial investigating the efficacy of preoperative S-1 plus oxaliplatin in patients with cStage III (cT3-4N1-3) gastric cancer (JCOG1509) is ongoing in Japan. The addition of immune checkpoint inhibitors to cytotoxic chemotherapy also seems promising and is being investigated in international randomized clinical trials. Although we have to await the final results of these studies, preoperative neoadjuvant chemotherapy is a promising treatment strategy and likely to become standard treatment for locally advanced gastric cancer in Japan.