Expanding the Use of HIPEC in Ovarian Cancer at Time of Interval Debulking Surgery to FIGO Stage IV and After 6 Cycles of Neoadjuvant Chemotherapy: A Prospective Analysis on Perioperative and Oncologic Outcomes

Background. Randomized data on patients with FIGO stage III ovarian cancer receiving <= 3 cycles of neoadjuvant chemotherapy (NACT) showed that hyperthermic intraperitoneal chemotherapy (HIPEC) after interval debulking surgery (IDS) improved patient's survival. We assessed the perioperative outcomes and PFS of FIGO stage IV and/or patients receiving up to 6 cycles of NACT undergoing IDS+HIPEC. Methods. Prospectively collected cases from January 1, 2019 to July 31, 2022 were included. Patients underwent HIPEC if: age >= 18 years but <75 years, body mass index <= 35 kg/m(2), ASA score <= 2, FIGO stage III/IV epithelial disease treated with up to 6 cycles of NACT, and residual disease <2.5 mm. Results. A total of 205 patients were included. No difference was found in baseline characteristics between FIGO Stage III and IV patients, whereas rate of stable disease after NACT (p = 0.004), mean surgical complexity score at IDS (p = 0.001), and bowel resection rate (p = 0.046) were higher in patients undergoing delayed IDS. A lower rate of patients with at least one G3-G5 postoperative complications was observed in FIGO stage IV versus FIGO stage III disease (5.3% vs. 14.0%; p = 0.052). This difference was confirmed at multivariable analysis (odds ratio [OR] 0.24; 95% confidence interval [CI] 0.07-0.80; p = 0.02), whereas age, SCS, bowel resection, and number of cycles did not affect postoperative complications. No difference in PFS was identified neither between FIGO stage III and IV patients (p = 0.44), nor between 3 and 4 versus > 4 cycles of NACT (p = 0.85). Conclusions. Because of the absence of additional complications and positive survival outcomes, HIPEC administration can be considered in selected FIGO stage IV and patients receiving > 4 cycles of NACT.