Since 1987 a prospectively compiled database at our institute has collected the data of 1,761 patients who underwent surgery for RCC. All the patients are followed in a specially dedicated out-patient ambulatory. For this study, patients who were taking insulin or oral anti-hyperglycemic drugs before surgery for RCC were considered as DM cases. Their clinical and pathologic features were compared with those of patients without DM. Then, limiting the analysis to non-metastatic patients, the Kaplan-Meier method was used to calculate survival functions and univariable and multivariable Cox regression models addressed time to RCC-related and non RCC-related mortality.
The data of 1,604 patients without DM and 157 with DM (prevalence 8.9 % ) have been analyzed; the latter were more frequently males, older, and with higher co-morbidity and with more asymptomatic, smaller, and low stage neoplasms, though with a higher grading. After a median follow-up time of 53.4 months (IQR 20-97 months), the factors that influenced RCC-related mortality were the presence of symptoms at diagnosis, tumor size, TMN staging, and grading, while those that influenced non-RCC-related mortality were age, gender, and co-morbidities, whereas the presence of DM showed no influence at all. Moreover, in patients without and with DM, progression rate (19.8 % vs. 15.1 % , P = 0.195) and RCC-related mortality rate (9.6 % vs. 5.3 % , P = 0.102) were also statistically equivalent.
In our experience, the prevalence of DM in RCC patients is close to 10 % . Such a condition does not determine any significant influence on prognosis of RCC.