Introduction/Background In March 2019, interval cytoreductive surgery (ICS) with hyperthermic intraperitoneal chemotherapy (HIPEC) became the standard of care for FIGO stage III ovarian cancer patients treated with neo-adjuvant chemotherapy in the Netherlands. The OVHIPEC-1 trial showed a bowel resection rate of 23% in both arms, with a significant difference in the stoma formation rate among patients undergoing bowel resection (43% in the non-HIPEC arm and 72% in the HIPEC arm). As there is no evidence that HIPEC is associated with a higher anastomotic leakage rate, surgeon’s preference has been suggested as an explanation. This study aims to analyse the rate of stoma formation after HIPEC implementation in national guidelines and compare it with the outcomes observed in the OVHIPEC-1 trial.

Methodology This observational cohort study included 132 patients treated with ICS + HIPEC between March 2019 and December 2022 from two high-volume gynaecological oncology centres in the Netherlands. The stoma rate and bowel complication rate were compared with the OVHIPEC-1 cohort.

Results Complete resection was achieved in 84.8% (n=112). Bowel resection was performed in 38 patients (28.8%). Two patients had anastomotic leakage (5.2%). The stoma rate was 15.8% (n=6) and was significantly lower compared to the OVHIPEC-1 trial cohort (p=0.000).

Conclusion After implementation of ICS with HIPEC as standard practice in selected patients, a significant decrease in the stoma formation rate was observed when compared to the OVHIPEC-1 cohort, despite a comparable rate of bowel resection. This suggests a learning curve among surgical teams, with less reluctance to perform HIPEC in combination with bowel anastomoses in patients with advanced ovarian cancer patients. These findings highlight the feasibility of the treatment and provide valuable insights for patient counseling.

Disclosures GSS has received institutional research support from Merck Sharp & Dohme, Agendia, AstraZeneca, Roche, and Novartis, and consulting fees from Biovica and Seagen. All other authors declare no competing interests.