Postoperative adjuvant chemotherapy in patients with gastric cancer based on the Nationwide Gastric Cancer Registry in Japan.

The nationwide registry of the Japanese Gastric Cancer Association contains data related to the efficacy of adjuvant chemotherapy and prognostic factors across this patient population; elderly patients with advanced resectable gastric cancer are especially prevalent. Here, we analyzed data from 34,931 patients, who were treated between 2011 and 2013 at 421 hospitals in Japan. Although adjuvant chemotherapy was effective overall, 75 years or older elderly patients had a worse prognosis compared to younger patients. The most administered adjuvant chemotherapy was S-1 monotherapy. Adjuvant S-1 monotherapy was also effective for patients with pT1N2, pT1N3, and pT3N0 stage II tumors, as well as patients with other stage II and III malignancies. Independent prognostic factors for poor overall and relapse-free survival in patients at both stage II and stage III were age 75 or older, male, preoperative Eastern Cooperative Oncology Group performance status (ECOG-PS) 1 or more, preoperative renal dysfunction, undifferentiated adenocarcinoma, undergoing total gastrectomy, open laparotomy, no adjuvant chemotherapy, D1 lymphadenectomy, residual tumor R1 or R2, and Clavien-Dindo classification grade II or higher. Age 75 or older, renal dysfunction, ECOG-PS 1 and total gastrectomy were also significant risk factors for postoperative complications and lower compliance with adjuvant chemotherapy. Our analysis also revealed that adjuvant chemotherapy after resection of cancer of gastric remnant and postoperative chemotherapy against CY1 gastric cancer were also effective. We conclude that adjuvant chemotherapy is effective for all stage II and III patients including age 75 or older gastric cancer patients, in addition to distal gastrectomy, proximal gastrectomy, and pylorus-preserving surgery to avoid total gastrectomy may improve surgical outcomes and quality of life for elderly patients.