Pilot study of a combination of S-1 and paclitaxel for patients with peritoneal metastasis from gastric cancer

This pilot study was carried out to evaluate the efficacy of chemotherapy for patients with peritoneal dissemination from gastric cancer or positive lavage cytology diagnosed by staging laparoscopy. Sixteen patients were enrolled. Paclitaxel was administered at 120 mg/m(2) on day 1 and S-1 was administered orally at 80 mg/m(2) for 14 consecutive days, followed by a 1-week rest, as one course. After five courses of this therapy, the primary gastric tumors were evaluated and second-look laparoscopy was performed for patients showing partial response or stable disease with clinical benefit. Partial response or stable disease with clinical benefit was confirmed in seven and five patients, respectively, and these patients underwent second-look laparoscopy. No viable cancer cells were detected on cytopathological investigation during second-look laparoscopy in 9 patients who underwent surgical treatment. The intent-to-treat response rate for gastric tumor was 44% and the rate of disappearance of peritoneal metastasis was 38% (6 cases) at surgery. The median survival time was 555 days. Leucopenia of grade 3 and neutropenia of grade 3 were recognized in two and three patients, respectively. This chemotherapy regimen may be an acceptable option for patients with peritoneal dissemination. We plan to study this regimen further in gastric cancer patients with peritoneal dissemination.