The clinical effect of conversion surgery for advanced gastric cancer patients with peritoneal metastasis

The prognosis of gastric cancer (GC) patients with peritoneal metastasis (PM) is extremely poor. We developed a new promising regimen combining intraperitoneal (i.p.) paclitaxel (PTX) with systemic PTX and S-1 chemotherapy for GC patients with PM. However, the value of conversion surgery (CS) for GC patients with PM remains unclear. This study aimed to clarify the clinical effect of CS from our updated previous report.

We retrospectively analyzed 50 GC patients, divided into chemotherapy alone (CTx; n=15) and conversion surgery intervention (CSI; n=35) groups. In the CTx group, chemotherapy was continued in responders, while in the CSI group, surgery was performed in chemotherapy-responders. The primary endpoint was overall survival (OS) of the two groups. The secondary endpoint was the safety of CS.

In the CTx group, 9 of 15 patients (60%) responded to chemotherapy. In the CSI group, PM disappeared in 22 of 35 patients (62.9%), all of whom underwent CS. Post-operative complications occurred in 2 patients (9%) who underwent CS. There were no treatment-related deaths. Regarding OS, there was no significant difference between the two groups [P=0.14; 95% confidence interval (CI), 0.3016-1.197], nor between chemotherapy-responders in the two groups (P=0.059; 95% CI, 0.1473-1.039). However, four patients in the CSI group have survived more than 5 years after CS.

CS may be a promising treatment strategy for some GC patients with PM who have responded to chemotherapy.