Elevated core body temperature during hyperthermic intraperitoneal chemotherapy does not impact postoperative outcomes

Background: Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) is an important treatment modality in the management of peritoneal surface malignancies. The effect of elevated core body temperature (CBT) during HIPEC on clinical outcomes is unclear. Methods: A retrospective review of patients who underwent HIPEC at a tertiary care institution between 2006 and 2019 with complete perfusion and anesthesia records was conducted. The cohort was stratified into two groups according to mean CBT recorded during HIPEC. Elevated CBT was defined as core temperature ≥ 38 °C. A supplemental analysis was performed with a higher threshold of 39.5 °C. Results: 147 patients were identified, with 100 (68 %) having elevated CBTs during HIPEC. Baseline characteristics were similar. The majority had peritoneal disease of colorectal and appendiceal origin. Peritoneal cancer index (PCI) scores and operative characteristics were similar between groups. HIPEC parameters such as perfusion flow rates, and inflow and outflow temperatures were comparable. Average CBT in both groups did not exceed 40 °. Postoperative course, 30-day complication rates and disease-free (median 7 months in normal CBT vs 18 months in elevated CBT, P = 0.116) and overall survival (median 50 months in normal CBT vs 76 months in elevated CBT, P = 0.569) were similar. Conclusion: Despite inflow temperatures of 43 °C, average CBT did not exceed 40 °C, demonstrating that HIPEC does not cause equivalent systemic hyperthermia. Patients experiencing elevated CBT during HIPEC have similar postoperative morbidity, mortality, and oncologic outcomes compared to those with normal CBT, suggesting that patients may be more tolerant of hyperthermia than previously reported. Synopsis: Research about hyperthermic intraperitoneal chemotherapy (HIPEC) has focused previously on chemotherapy agents and perfusion parameters, but there is a lack of data investigating the effect of core body temperatures (CBT) on clinical outcomes. The majority of patients have an elevated CBT during HIPEC, but on average do not exceed 40 °C. These patients have similar postoperative and oncologic outcomes, suggesting that patients are more tolerant of elevated CBTs than previously reported.