Pre‐existing type 2 diabetes is an adverse prognostic factor in patients with renal cell carcinoma

BACKGROUND: Diabetes is a risk factor for various cancers, but its prognostic role in renal cell carcinoma (RCC) is controversial and understudied. This study investigated the prognostic value of type 2 diabetes (T2D) in RCC patients. METHODS: The clinicopathological and follow‐up data of 451 RCC patients undergoing radical or partial nephrectomy at the First Hospital of Shanxi Medical University from 2013 to 2018 were reviewed. Associations of T2D with clinicopathological parameters of RCC were evaluated using the Kaplan‐Meier method for survival estimates and Cox regression univariate and multivariate analyses. RESULTS: Of 451 patients, 74 (16.4%) had T2D. These patients were older, had a higher body mass index, higher incidence rates of hypertension and cardiovascular morbidity, a higher rate of laparoscopic surgery, and smaller neoplasms (all P < .05). Patients with T2D exhibited shorter overall survival (OS; P = .009), cancer‐specific survival (CSS; P = .043), and recurrence‐free survival (RFS; P = .008) than patients without T2D. Fuhrman grade (hazard ratio [HR] 2.542, 95% confidence interval [CI] 1.115‐5.795, P = .026) and T2D (HR 3.391, CI 1.458‐7.886, P = .005) were independent predictors of OS; T2D was an independent predictor of CSS (HR = 4.637, 95% CI 1.420‐15.139, P = .011) and RFS (HR 3.492, 95% CI 1.516‐8.044, P = .003). CONCLUSIONS: Renal cell carcinoma patients with T2D have a shorter OS and higher recurrence rate and mortality risk than those without T2D.