Association between diabetes mellitus and oncological outcomes in bladder cancer patients undergoing radical cystectomy

To determine the association between diabetes mellitus and oncological outcomes in urothelial bladder cancer patients undergoing radical cystectomy.From January 2004 to December 2014, 200 non-metastatic urothelial bladder cancer patients who underwent radical cystectomy were divided into two groups according to diabetes mellitus status at the time of surgery. Kaplan-Meier and Cox regression analysis were used to assess the association between diabetes mellitus and urothelial bladder cancer recurrence-free, cancer-specific and overall mortality.Of the 200 patients, 28 (14%) had diabetes mellitus and presented similar preoperative factors and pathological findings after radical cystectomy, including pathological stage, grade, lymph node invasion and positive surgical margin compared with non-diabetes mellitus patients (n = 172). The 5-year cancer-specific survivals were 92.3% and 62.1% in the non-diabetes mellitus and diabetes mellitus groups, respectively (P = 0.022). Multivariate Cox regression analysis showed that diabetes mellitus was a significant predictor for cancer-specific mortality (hazard ratio 1.785, P = 0.038). The 5-year overall survival rate was 92.1% and 59.4% in the non-diabetes mellitus and diabetes mellitus groups, respectively (P = 0.014), and diabetes mellitus was a significant factor for overall mortality by multivariate Cox regression analysis (hazard ratio 1.281, P = 0.042).Among bladder cancer patients who underwent radical cystectomy, the diabetes mellitus patients had worse cancer-specific mortality and overall mortality outcomes than the non-diabetes mellitus patients. The mechanism of association between diabetes mellitus and urothelial bladder cancer should be investigated to validate the present results in a future prospective study.