Association of intraoperative hypothermia with oncologic outcomes following radical cystectomy

Introduction: Intraoperative hypothermia (IOH) has been suggested to adversely impact outcomes following surgery. The objective of this study was to evaluate the association between IOH and survival following radical cystectomy (RC). Methods: Patients who underwent RC for bladder cancer from 2003 to 2018 were identified in our cystectomy registry. Intraoperative temperatures were extracted from the anesthesia record. IOH was defined as a median intraoperative temperature <36°C, and severe IOH as ≤ 35°C. Time under 36°C was assessed as a continuous variable. Recurrence-free survival (RFS), cancer-specific survival (CSS), and overall survival (OS) were estimated using the Kaplan-Meier method. Associations between IOH and outcomes were assessed with multivariable Cox proportional hazards models. Results: A total of 852 patients were identified, among whom 274 (32%) had IOH. Median follow up among survivors was 4.9 years (IQR 2.4–8.7), during which time 483 patients died, including 343 from bladder cancer. Two-year survival was not significantly different between patients with and without IOH (CSS: 74% vs. 71%, P= 0.31; OS: 68% vs. 67%, P= 0.13). Following multivariable adjustment, neither IOH nor time under 36°C was significantly associated with survival. A total of 37 patients (4.3%) had severe IOH. These patients were observed to have significantly lower 2-year OS (56% vs. 68%, P= 0.005); however, this association did not remain statistically significant after multivariable adjustment (P= 0.92). Conclusion: IOH was not independently associated with survival following RC. These data do not support IOH as a prognostic factor for cancer outcomes among patients undergoing RC.