Controlling perfusion temperature relates to better outcomes after cytoreductive surgery and hyperthermic...

Temperature variability during cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) perfusion may affect cytotoxicity. We aimed to characterize an optimal thermal dose during perfusion and assess its impact on outcomes after CRS/HIPEC.

A retrospective cohort study was conducted (2004-2024) including CRS/HIPEC patients with complete cytoreduction (CC-0/1) and 90-minute perfusion. Using the minimum p-value approach to maximize overall survival (OS), an optimal combination of minimum perfusion temperature and time above such temperature was identified. Patients were classified as PASS if achieving these conditions, or FAIL otherwise. Subgroup multivariable Cox regression was performed.

Optimal conditions were an outflow temperature of ≥40.5 °C for ≥70 % of perfusion time (PASS). Of 755 cases, 531 (70.3%) were PASS and 224 (29.7%) FAIL. Perfusion agents included mitomycin-C (n = 465, 63.1%), melphalan (n = 122, 16.5%), and platinum-based (n = 150, 20.4%). Groups were balanced by age, primary tumor site, peritoneal cancer index (PCI), cytoreduction degree, and major complications. FAIL had more males (p < 0.01), higher BMI (p < 0.01), and longer operative times (p = 0.03). Median follow-up was 80.4 months. PASS had significantly longer median OS (149.4 vs 80.3 months, p < 0.01) than FAIL. Subgroup multivariable regression showed a survival benefit of PASS conditions with mitomycin-C and melphalan, but not with platinum agents. PASS conditions were also associated with improved OS in CC-0 and PCI<25.

Maintaining outflow temperatures of ≥40.5°C for ≥70% of perfusion time was associated with improved survival. Thermal dose should be characterized and carefully controlled throughout the procedure. This benefit varied by chemotherapy agent and patient subgroup, warranting further investigation.