Neoadjuvant systemic and hyperthermic intraperitoneal chemotherapy combined with cytoreductive surgery for gastric cancer patients with limited peritoneal metastasis: a prospective cohort study

Background There is no currently available treatment for peritoneal metastasis of gastric cancer. This phase II study aimed to evaluate the efficacy and safety of neoadjuvant systemic chemotherapy and hyperthermic intraperitoneal chemotherapy (HIPEC) combined with cytoreductive surgery (CRS) for the treatment of these patients. Methods Neoadjuvant chemotherapy comprised two cycles of HIPEC and four cycles of S-1 plus paclitaxel. HIPEC was administered intraperitoneally with paclitaxel (75 mg/m(2)). For systemic chemotherapy, paclitaxel was administered intravenously(150 mg/m(2)) on day 1, and S-1 was administered orally(80 mg/m(2)/day)on days 1-14 of a 3-week cycle. Another two cycles of HIPEC and four cycles of S-1 plus paclitaxel were administered after second diagnostic staging laparoscopy or CRS. The primary endpoints were treatment efficiency and safety; the secondary endpoint was 3-year overall survival (OS). Results A total of 40 patients were enrolled and 38 patients have been analyzed. Of these, 18 (47.4%) patients received neoadjuvant systemic chemotherapy, HIPEC and CRS (conversion therapy group), while 20 patients received only chemotherapy and HIPEC (palliative chemotherapy group). Median OS was markedly improved in the conversion therapy group (21.1 months, 95% confidence interval [CI] 16.7-25.6 months) in comparison with the palliative chemotherapy group(10.8 months, 95%CI 7.3-14.2 months, p = 0.002). After neoadjuvant systemic chemotherapy and HIPEC, a second laparoscopic exploration was performed, and the prognosis of patients with low peritoneal cancer index (PCI) (PCI < 6) was significantly better than that of patients with high PCI (PCI >= 6)(20.1 vs.11.3 months, p = 0.006). Conclusion Neoadjuvant systemic chemotherapy and HIPEC combined with CRS is safe and feasible, and could potentially improve the prognosis of gastric cancer patients with limited peritoneal metastasis. However, further clinical trials are still warranted.