Author(s): Kodera Y, Ishiyama A, Yoshikawa T, Kinoshita T, Ito S
BACKGROUND: The outcome of stage III gastric cancer patients treated by D2 dissection followed by adjuvant chemotherapy with S-1 remains unsatisfactory. Moreover, some patients with a preoperative diagnosis of stage II/III turn out to be stage IV after surgical exploration, and a standard postoperative treatment for this population has not been established. METHODS: A feasibility study of postoperative S-1/cisplatin (CDDP) was performed with patients who underwent gastrectomy for what turned out to be a stage IV gastric cancer. The primary endpoint of the trial was the relative dose intensity during five courses of S-1/CDDP. Several criteria to skip, postpone, or reduce the dose had been predetermined. RESULTS: Between 2007 and 2009, 31 patients were accrued, including 19 patients who were positive for peritoneal washing cytology, 6 with peritoneal seeding, 5 with metastasis to the paraaortic nodes, and 4 with other distant metastases. Only 7 patients completed five cycles as planned (median, two cycles). The median relative dose intensities of S-1 and CDDP were 37% and 40%, respectively. Causes of treatment failure were failure to fulfill criteria for starting a new course within 5 weeks of the last administration of S-1 in 7, patient refusal in 6, disease recurrence/progression in 4, need to reduce dose by two levels in 4, and two successive skips of CDDP in 3 patients. The median progression-free survival time of all patients was 363 days. CONCLUSIONS: Although promising in the neoadjuvant and advanced/metastatic setting, S-1/CDDP is too toxic as a postgastrectomy treatment for Japanese patients.