Cytoreductive surgery (CRS) and heated intraperitoneal chemotherapy (HIPEC) for peritoneal mesothelioma: Canadian practices and outcomes.

INTRODUCTION: Peritoneal mesothelioma (PM) is a rare malignancy originating from the peritoneal lining. Cytoreductive surgery (CRS) and heated intraperitoneal chemotherapy (HIPEC) is the standard-of-care for patients with isolated PM. Due to a paucity of prospective data there are several different HIPEC protocols. The aims of this study are to describe the CRS and HIPEC protocols for PM and patient outcomes across Canada. METHODS: A multicenter retrospective study was performed on patients diagnosed and treated for PM with CRS and HIPEC in four major peritoneal disease centers in Canada between 2000 and 2021. Data on patient characteristics, treatment patterns, postoperative morbidity, recurrence, and survival were collected. RESULTS: A total of 72 patients were identified. Mean age was 52 years (17-75) and 37.5% were male. Epithelioid (70.1%) and multicystic (13%) mesothelioma were the most common subtypes. Twenty-one patients (30%) were treated with neoadjuvant chemotherapy. CRS and HIPEC was performed in 64 patients (91.4%). Of these, the mean PCI was 22 (2-39) and cisplatin+doxorubicin was the most common HIPEC regimen (n = 33, 51.6%). A semi-closed coliseum technique was used in 68.8% of HIPECs and the mean duration of surgery was 486 min (90-1052). Clavien-Dindo III or IV complications occurred in 12 patients (16.9%). With a median follow-up of 24 months (0.2-104.4), we found a 5-year overall survival of 61% and a 5-year recurrence-free survival of 35%. CONCLUSION: CRS and HIPEC is a safe and effective treatment modality for well-selected patients with PM, with some achieving prolonged survival.

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.