(ChemotherapyAdvisor) – Combination chemotherapy with S-1—oral tegafur, gimeracil, and oteracil potassium—and intravenous (IV) and intraperitoneal (IP) paclitaxel was found to be “well tolerated and very effective” in patients with gastric cancer and peritoneal metastasis, according to a study presented during the 66th Annual Society of Surgical Oncology (SSO) Cancer Symposium, held in National Harbor, MD.

“Peritoneal metastasis is the most frequent and life-threatening type of metastasis in gastric cancer,” reported Joji Kitayama, MD, and colleagues from the Department of Surgical Oncology at the University of Tokyo, Tokyo, Japan. Despite recent advances in chemotherapeutic agents, regimens administered solely by IV “cannot satisfactorily control the peritoneal metastasis in gastric cancer,” they added. Although IP chemotherapy has been proposed as a treatment option, its clinical efficacy for peritoneal lesions has not been examined in gastrointestinal cancer.

The investigators treated 100 patients with peritoneal metastasis of gastric cancer with S-1 plus paclitaxel administered via both the IV and IP route. Paclitaxel 20 mg/m2 was administered IP from the subcutaneous implanted peritoneal access port; 50 mg/m2 IV was given on days 1 and 8. The S-1 dosage was 80 mg/m2 per day, administered for 14 consecutive days, followed by 7 days of rest. As necessary, gastrectomy was performed in salvage setting.

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Median survival time for the 100 patients was 23.5 months. “In all patients, laparoscopy was performed under general anesthesia before and after chemotherapy, and the change in peritoneal metastases was macroscopically evaluated by video-recorded picture,” Dr. Kitayama reported.

In the 60 patients who showed apparent shrinkage of peritoneal lesions with negative peritoneal cytology after a median of three courses of treatment (range, 2-16 courses), gastrectomy with nodal dissection was performed; R0 resection was achieved in 35 cases. Median survival of these 60 patients was 34.5 months and 1-year overall survival was 83%. The 40 patients who did not undergo gastrectomy had a median survival of 13 months and 1-year overall survival of 39%. “Anastomotic leakage and pancreatic fistula developed in two cases but no mortality was observed,” they noted.

Systemic chemotherapy combined with repeated IP administration of paclitaxel following salvage gastrectomy “is a promising strategy for peritoneal carcinomatosis in gastrointestinal cancer,” they concluded.

The abstract (#83) for this presentation is available at the 66th Annual SSO Cancer Symposium’s website.