Intraperitoneal Administration of Paclitaxel Combined with S-1 Plus Oxaliplatin as Induction Therapy for Patients with Advanced Gastric Cancer with Peritoneal Metastases

Background Intraperitoneal (IP) administration of paclitaxel (PTX) has a great pharmacokinetic advantage to control peritoneal lesions and can be combined with various systemic chemotherapies. In this study, we evaluate the efficacy and tolerability of a combination of IP-PTX and systemic S-1/oxaliplatin (SOX) for induction chemotherapy for patients with peritoneal metastases (PM) from gastric cancer (GC). Patients and Methods Patients with GC who were diagnosed as macroscopic PM (P1) or positive peritoneal cytology (CY1) by staging laparoscopy between 2016 and 2019 were enrolled. PTX was IP administered at 40 mg/m(2) on days 1 and 8. Oxaliplatin was IV administered at 100 mg/m(2) on day 1, and S-1 was administered at 80 mg/m(2)/day for 14 consecutive days, repeated every 21 days. Survival time and toxicities were retrospectively explored. Results Forty-four patients received SOX + IP-PTX with a median (range) of 16 (1-48) courses, although oxaliplatin was suspended due to the hematotoxicity or intolerable peripheral neuropathy in many patients. The 1-year overall survival (OS) rate was 79.5% (95% CI 64.4-88.8%) with median survival time of 25.8 months. Gastrectomy was performed in 20 (45%) patients who showed macroscopic shrinkage of PM with a 1-year OS rate of 100% (95% CI 69.5-100%). Grade 2 and 3 histological responses was achieved in four (20%) and one (5%) patients. Grade 3/4 toxicities included neutropenia (11%), leukopenia (39%), and anemia (14%). There were no treatment-related deaths. Conclusions Combination chemotherapy using SOX + IP-PTX regimen is highly effective and recommended as induction chemotherapy for patients with PM from GC.

Automated summary

The combination chemotherapy using SOX + IP-PTX regimen showed high efficacy in patients with peritoneal metastases from gastric cancer, with a 1-year overall survival rate of 79.5%. Common toxicities included neutropenia, leukopenia, and anemia, but there were no treatment-related deaths.