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

Background: 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.

Methods: 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.

Results: 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.

Conclusions: 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.