(PM P17) A Multi-institutional Analysis of Major Organ Resection in Cytoreductive Surgery with Hyperthermic Intraperitoneal Chemotherapy for Peritoneal Mesothelioma

Introduction: Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) is thought to confer a survival advantage for patients with peritoneal mesothelioma (PM). In this study, we evaluated the impact of MOR on post-operative outcomes and overall survival (OS).

Methods: The US HIPEC collaborative database (2000-2017) was reviewed for PM patients who underwent CRS/HIPEC. MOR was defined as total or partial resection of the diaphragm, stomach, spleen, pancreas, small bowel, colon, rectum, kidney, ureter, bladder, and/or uterus. MOR was categorized as 0, 1, or 2+ organs. Frequency and survival analyses were performed.

Results: 174 patients were identified. Median PCI was 16 (3-39). 94 patients had MOR-0 (54%), 45 (25.9%) MOR-1 and 35 MOR-2+ (20.1%). There was no difference in MOR by histologic subtype or rate of CC 0/1 (71%, 76.2% and 84.4%, respectively). Complications were higher in the MOR-1 or 2+ group (57.8%, and 74.3%) compared to MOR-0 (48.9%, p = 0.035). Median length of stay (LOS) was also higher in the MOR-1, 2+ groups (10 and 11 days) compared the MOR-0 cohort (9 days, p=0.005). The greatest association to mortality was CC score 2/3 (HR 4.37; 95% CI, 2.12-9.01). MOR was not associated with increased mortality when adjusted for potential confounders (MOR-1 [HR 1.92; 95% CI, 0.85-4.34] MOR-2+ [HR 1.80; 95% CI, 0.71-4.54]).

Conclusion: Although MOR was associated with more complications and longer LOS in patients undergoing CRS/HIPEC for PM, it did not predict worse OS. MOR should be considered if necessary to achieve a complete cytoreduction for PM patients.