This study evaluated the addition of hyperthermic intraperitoneal chemotherapy (HIPEC) to interval cytoreductive surgery in patients with stage III epithelial ovarian cancer. The trial was multicenter, open-label, and phase 3, involving 245 patients who had at least stable disease after three cycles of neoadjuvant chemotherapy with carboplatin and paclitaxel. Patients were randomly assigned to undergo interval cytoreductive surgery with or without HIPEC. The primary endpoint was recurrence-free survival, and overall survival and side-effect profiles were secondary endpoints. The results showed that HIPEC significantly improved recurrence-free survival (hazard ratio, 0.66; 95% CI, 0.50 to 0.87; P=0.003) and overall survival (hazard ratio, 0.67; 95% CI, 0.48 to 0.94; P=0.02) compared to surgery alone. The median recurrence-free survival was 14.2 months in the HIPEC group and 10.7 months in the surgery group, and the median overall survival was 45.7 months in the HIPEC group and 33.9 months in the surgery group. The incidence of adverse events was similar between the two groups. The study concluded that HIPEC added to interval cytoreductive surgery improved outcomes in patients with stage III epithelial ovarian cancer without increasing side effects.This study evaluated the addition of hyperthermic intraperitoneal chemotherapy (HIPEC) to interval cytoreductive surgery in patients with stage III epithelial ovarian cancer. The trial was multicenter, open-label, and phase 3, involving 245 patients who had at least stable disease after three cycles of neoadjuvant chemotherapy with carboplatin and paclitaxel. Patients were randomly assigned to undergo interval cytoreductive surgery with or without HIPEC. The primary endpoint was recurrence-free survival, and overall survival and side-effect profiles were secondary endpoints. The results showed that HIPEC significantly improved recurrence-free survival (hazard ratio, 0.66; 95% CI, 0.50 to 0.87; P=0.003) and overall survival (hazard ratio, 0.67; 95% CI, 0.48 to 0.94; P=0.02) compared to surgery alone. The median recurrence-free survival was 14.2 months in the HIPEC group and 10.7 months in the surgery group, and the median overall survival was 45.7 months in the HIPEC group and 33.9 months in the surgery group. The incidence of adverse events was similar between the two groups. The study concluded that HIPEC added to interval cytoreductive surgery improved outcomes in patients with stage III epithelial ovarian cancer without increasing side effects.