Efficacy of S-1 for gastric cancer patients with positive peritoneal lavage cytology.

BACKGROUND/AIMS: Positive peritoneal lavage cytology (PLC) is a strong predictor of subsequent frank peritoneal dissemination. The prognosis for patients with positive PLC is as poor as with macroscopic peritoneal dissemination. We examined the clinical efficacy of S-1 chemotherapy against gastric cancer with positive PLC after macroscopically curative resection.

METHODOLOGY

Among our gastric cancer patients proving to have positive PLC after operation, 17 treated between 2000 and 2005 and 20 treated between 1986 and 1999 respectively represented S-1 and non-S-1 groups, between which we compared survival rates. S-1 was administered orally twice daily at a dose of 80 mg/m2/day for 28 consecutive days followed by a 14-day pause, thus repeating the cycle every 6 weeks.

RESULTS

S-1 was administered for more than 2 cycles in all patients (median, 10 cycles). Grade 3 adverse reactions to S-1 occurred in two patients. Other adverse reactions were grade 2 or less. Cumulative survival in the S-1 group was better than in the non-S-1 group (p=0.0034), with 1- and 3-year survival rates of 87.5% and 71.6% vs. 59.0% and 17.1%.

CONCLUSIONS

S-1 is effective as postoperative chemotherapy for gastric cancer patients with positive PLC after macroscopically curative resection.