Predictors of Small Bowel Obstruction Post-Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy

BACKGROUND: Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) for peritoneal malignancies carries considerable morbidity; however, the significance of postoperative small bowel obstruction (SBO) is not well defined. We aim to identify predictors for post-CRS/HIPEC SBO and their oncologic associations. METHODS: A retrospective review was conducted of all CRS/HIPEC cases performed at a surgical oncology center (2013-2018). Patient demographics, tumor characteristics, perioperative factors, and province-wide hospital readmissions were analyzed. Descriptive statistics were used for baseline characteristics, multivariate logistic regression for predictors of SBO at 1 year, and Kaplan-Meier method with log-rank test for survival analysis. RESULTS: A total of n = 97 CRS/HIPEC procedures were performed for diagnoses of low-grade appendiceal mucinous neoplasm (44%), high-grade appendiceal adenocarcinoma (8%), colorectal adenocarcinoma (34%), and mesothelioma (9%). The median peritoneal carcinomatosis index (PCI) score was 16. Cumulative incidence of post-CRS/HIPEC SBO readmission was 24% at 1 year and 38% at 2 and 3 years. Of 29 patients readmitted with SBO, 14 (48%) had more than one readmission for SBO, and nine surgeries were performed for obstruction. Multivariate regression identified significant independent predictors of SBO within 1-year post-CRS/HIPEC as high-grade appendiceal or colorectal primaries (odds ratio [OR] 4.58, p = 0.02) and PCI ≥ 20 (OR 3.27, p = 0.05). Overall survival (OS) was worse in patients readmitted with SBO within 1 year compared to those without (3-year OS 58% vs. 75%, p = 0.017). CONCLUSION: SBO is the most common readmission diagnosis post-CRS/HIPEC and is associated with worse survival. High-grade appendiceal and colorectal primary tumors and PCI ≥ 20 are predictors for SBO.