A comparison of multimodality treatment: two and four courses of neoadjuvant chemotherapy using S-1/CDDP or S-1/CDDP/docetaxel followed by surgery and S-1 adjuvant chemotherapy for macroscopically resectable serosa-positive gastric cancer: a randomized phase II trial (COMPASS-D trial).

This randomized Phase II trial will compare the outcome of neoadjuvant chemotherapy using two and four courses of S-1 plus cisplatin or S-1 plus cisplatin plus docetaxel by a two-by-two factorial design for patients with macroscopically resectable serosa-positive gastric cancer. After neoadjuvant chemotherapy, patients will receive D2 gastrectomy followed by S-1 chemotherapy for 1 year postoperatively. The primary endpoint is the 3-year overall survival. The sample size is 120 for the two hypotheses: the superiority of four courses compared with two courses and the superiority of S-1 plus cisplatin plus docetaxel compared with S-1 plus cisplatin. This trial will be able to define the more suitable number of cycles and better regimen of neoadjuvant chemotherapy for gastric cancer.