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.