Small bowel obstruction (SBO) affects ~ 30% of ovarian cancer (OC) patients, leading to readmission, debilitating symptoms, and death within one year. Cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) effectively controls peritoneal disease. We investigated primary CRS/HIPEC’s impact on SBO and obstruction-free survival (OFS) in OC patients.

A retrospective single-center cohort study of stage III/IV OC patients treated with primary optimal CRS (2014–2022) was performed. Patients who underwent upfront CRS/HIPEC vs. CRS only were matched for histology, age (> 65 years), extent of disease, FIGO stage, and surgery year, using a propensity scored full matching algorithm. CRS/HIPEC effect on OFS was determined using a weighted cox-regression model. OFS was measured from surgery to SBO/death.

Overall, 102 patients were included, 29 underwent CRS/HIPEC and 73 CRS only. CRS/HIPEC had higher median number of upper abdominal procedures (4 [IQR: 3–5] vs. 1 [IQR: 0–4], p < 0.01). Postoperative major morbidity was similar (p = 0.62). After a median follow-up of 88.8 months, SBO occurred in 24.1% (n = 7) CRS/HIPEC vs. 42.0% (n = 34) CRS only (p = 0.12). Most SBOs were partial (CRS/HIPEC: 71.4%, CRS: 55.9%) and managed conservatively (CRS/HIPEC: 71.4%, CRS: 67.6%). Median OFS was 42.9 vs. 20.0 months (HR: 0.50 [95% CI 0.27–0.93], p = 0.028). One-year survival after initial SBO was 85.7% vs. 44.7%, respectively (HR: 0.79 [95% CI 0.39–1.61], p = 0.512).

SBO after upfront CRS/HIPEC for OC occurred less frequently, was delayed, and had lower 1-year mortality compared to CRS alone. CRS, which includes upper abdominal exploration/surgery, coupled with HIPEC could enhance long-term peritoneal disease control in OC patients.