Retrospective analysis of 45 consecutive patients with advanced gastric cancer treated with neoadjuvant chemotherapy using an S-1/CDDP combination.

Background: Standard treatment for highly advanced gastric cancer (AGC) has not been established yet. Neoadjuvant chemotherapy (NAC) represents a promising approach, which may improve the prognosis of AGC. In this study, we analyzed the feasibility and efficacy of NAC with S-1 (TS-1)/cisplatin CDDP in order to design appropriate clinical trials for AGC.

Methods: Results for a series of 45 consecutive patients with AGC treated with S-1/CDDP induction chemotherapy since January 2002 were analyzed retrospectively.

Results: The primary tumor was resected in 36 of the 45 patients (resectability, 80.0%). Progression of the disease during chemotherapy was observed in 1 patient only (2.2%). No treatment-related deaths occurred, and serious adverse effects (grade 3-4) were noted in only 2.2% of the patients. The overall median survival time was 1.82 years. Especially noteworthy is that, in patients with highly advanced disease (pretreatment [c]-stage IV; n = 27), resectability was 66.7% and curative (R0) resection was possible in 10 patients. The median survival times for c-stage IV patients who had total, curative, and noncurative resections were 20.8, 22.3 and 12.6 months, respectively. R0 resection was possible for all c-stage III patients (n = 17), with a 2-year overall survival of 90.9%. The downstaging rate was 55.6% (20/36), resulting in a significantly improved prognosis for the downstaged patients (P = 0.012).

Conclusion: Induction chemotherapy using S-1/CDDP for AGC appears to be a safe and promising treatment. We have therefore started two independent multiinstitutional clinical trials to evaluate the efficacy of this treatment.