Hyperthermic intraperitoneal chemotherapy (HIPEC) was evaluated in a phase 3 trial for patients with stage III epithelial ovarian cancer. The study randomly assigned 245 patients who had stable disease after three cycles of neoadjuvant chemotherapy to undergo interval cytoreductive surgery with or without HIPEC. HIPEC was administered at the end of surgery using cisplatin at a dose of 100 mg/m². The primary endpoint was recurrence-free survival, with overall survival and side-effect profiles as secondary endpoints. In the intention-to-treat analysis, 89% of patients in the surgery group and 81% in the surgery-plus-HIPEC group experienced disease recurrence or death. The median recurrence-free survival was 10.7 months in the surgery group and 14.2 months in the surgery-plus-HIPEC group. At a median follow-up of 4.7 years, 62% of patients in the surgery group and 50% in the surgery-plus-HIPEC group had died. The median overall survival was 33.9 months in the surgery group and 45.7 months in the surgery-plus-HIPEC group. The percentage of patients with grade 3 or 4 adverse events was similar in both groups. The addition of HIPEC to interval cytoreductive surgery resulted in longer recurrence-free survival and overall survival compared to surgery alone, without an increase in side effects. HIPEC was feasible and showed consistent benefits across different subgroups. The study concluded that HIPEC plus interval cytoreductive surgery improved survival outcomes in patients with stage III ovarian cancer. The trial was funded by the Dutch Cancer Society.Hyperthermic intraperitoneal chemotherapy (HIPEC) was evaluated in a phase 3 trial for patients with stage III epithelial ovarian cancer. The study randomly assigned 245 patients who had stable disease after three cycles of neoadjuvant chemotherapy to undergo interval cytoreductive surgery with or without HIPEC. HIPEC was administered at the end of surgery using cisplatin at a dose of 100 mg/m². The primary endpoint was recurrence-free survival, with overall survival and side-effect profiles as secondary endpoints. In the intention-to-treat analysis, 89% of patients in the surgery group and 81% in the surgery-plus-HIPEC group experienced disease recurrence or death. The median recurrence-free survival was 10.7 months in the surgery group and 14.2 months in the surgery-plus-HIPEC group. At a median follow-up of 4.7 years, 62% of patients in the surgery group and 50% in the surgery-plus-HIPEC group had died. The median overall survival was 33.9 months in the surgery group and 45.7 months in the surgery-plus-HIPEC group. The percentage of patients with grade 3 or 4 adverse events was similar in both groups. The addition of HIPEC to interval cytoreductive surgery resulted in longer recurrence-free survival and overall survival compared to surgery alone, without an increase in side effects. HIPEC was feasible and showed consistent benefits across different subgroups. The study concluded that HIPEC plus interval cytoreductive surgery improved survival outcomes in patients with stage III ovarian cancer. The trial was funded by the Dutch Cancer Society.