Emma M. Bradley

Comparison of Outcomes after Cytoreductive Surgery with Hyperthermic Intraperitoneal Chemotherapy Among Patients with Non-Mucinous vs Mucinous Tumors

Background Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) is well established for mucinous cancers with peritoneal dissemination. Its role for non-mucinous tumors is less defined. This study compares outcomes between mucinous and non-mucinous cancer patients undergoing CRS-HIPEC to better understand therapeutic impact. Methods A prospectively maintained database of CRS-HIPEC patients at an academic tertiary referral center from 2011-2023 was analyzed, including patients with appendiceal, colorectal, gastric, ovarian tumors, and soft tissue sarcomas. Survival outcomes were assessed using Kaplan Meier curves and multivariate Cox-proportional hazards models. Results Among 195 patients, 55 (28%) had non-mucinous cancers and 140 (72%) mucinous tumors. The non-mucinous group had lower PCI (median 9 vs 14, P < 0.0001) was more frequently high grade (43.6% vs 22.9%, P = 0.004) with lymph node metastases (65.5% vs 17.1%, P < 0.0001). Length of stay, 30-day readmissions, and Clavien Dindo scores were similar between groups. There was no significant difference in overall (aHR 1.67, 95% CI 0.84-3.33) or cancer-specific survival (aHR 1.34, 95% CI 0.60-3.00) between groups. Non-mucinous patients did have a higher risk of cancer progression (aHR 2.50 95% CI 1.43-4.36), although this was primarily driven by differences in the appendiceal subgroup and was not seen in colorectal cancer patients. Discussion Despite differential loco-regional features, non-mucinous cancer patients had similar survival after CRS-HIPEC. Differences in progression were primarily seen in those with appendiceal cancers, not colorectal tumors. These findings support the use of CRS-HIPEC across histologic subtypes, contributing to prognostication and risk-stratification for patients with differing cancer histopathology.