Perioperative Hypothermia is a Prognostic Factor of Cystectomy Especially for Stage II Muscle-Invasive Bladder Cancer
Cystectomy is the standard treatment for muscle-invasive bladder cancer (MIBC). However, its risk factors and biomarkers identified as a prognostic factor such as postoperative recurrence can only be found in the pathological findings. In recent years, circulating tumor cells (CTCs) have been attracting much attention because it is considered that preventing postoperative engraftment of CTCs may reduce postoperative recurrence. It is also well known that hypothermia reduces humoral immunity of IL-6 and migration capacity of lymphocyte, which has traditionally been a contentious issue of the association between perioperative hypothermia and immunodeficiency in the fields of surgery and anesthesiology. These led us to the assumption that perioperative hypothermia may induce immunodeficiency and promote engraftment of CTCs and subsequently a poor prognosis. In this study, we compared the prognosis of cystectomy performed for MIBC between the hypothermia group and the normothermia group.
Data were collected from a total of 124 patients who underwent cystectomy for MIBC at our department between 2003 and 2016. The patients were divided into the 2 groups according to the lowest perioperative body temperature, i.e., the hypothermia group (
There was no difference in the patient characteristics between the 2 groups. The hypothermia group was significantly likely to have a recurrence within 12 months (P=0.013). Disease-Free Survival (DFS) was significantly low in the hypothermia group compared with the normothermia group (16.0 vs. 72.0 months; P=0.022). Overall Survival (OS) was relatively short at 29 months in the hypothermia group compared with 109 months in the normothermia group (P=0.062), with no significant difference. Compared by disease stages, there was no significant difference in both DFS and OS among stage III and IV patients. Whereas among stage II patients, both DFS and OS were significantly shorter in the hypothermia group than in the normothermia group (P=0.0042, P=0.014, respectively). On multivariate analysis, perioperative hypothermia was also found to be the independent factor of postoperative recurrence among the stage II patients (P=0.011).
The perioperative hypothermia group had a poor prognosis after cystectomy for MIBC. Perioperative hypothermia was significantly poor especially among stage II patients, suggesting that it can be a prognostic factor.