A phase II trial of perioperative chemotherapy involving a single intraperitoneal administration of paclitaxel followed by sequential S-1 plus intravenous paclitaxel for serosa-positive gastric cancer.

BACKGROUND AND OBJECTIVES: We carried out a phase II trial to evaluate the feasibility, efficacy, and tolerability of perioperative chemotherapy including single intraperitoneal(IP) administration of paclitaxel(PTX) followed by intravenous(IV) administrations of PTX with S-1 in a neoadjuvant setting for serosa-positive gastric cancer. METHODS: Patients with cT4a gastric cancer were enrolled. A laparoscopic survey was performed before study inclusion for the confirmation of serosal invasion, negative lavage cytology, and negative peritoneal metastasis. IP PTX (80 mg/m(2)) was administered, followed by systemic chemotherapy. Surgery was performed after the completion of chemotherapy. The primary endpoint was the treatment completion rate. RESULTS: 37 patients were recruited. The treatment completion rate was 67.6% (25/37; 90% CI, 52.8-80.1%), which was significantly higher than 50%; we set this as a threshold value (P = 2.4% [one-sided]). 14 patients had target lesions; of these, 10 showed a partial response (71.4%), three had stable disease (21.4%), and one had progressive disease(7.2%). The response rate was 71.4% (10/14). All patients underwent gastrectomy with D2 lymph node dissection. The 3- and 5-year OS rates were 78.0 and 74.9%, respectively. CONCLUSIONS: Perioperative chemotherapy including neoadjuvant IP PTX followed by sequential IV PTX with S-1 for serosa-positive gastric cancer is feasible, safe, and efficient.