Co-existing prostate cancer and diabetes mellitus: Implications for patient outcomes and care

Objective: To investigate how diabetes mellitus (DM) impacts short-term overall survival (OS) for patients with prostate cancer and to examine how prostate cancer impacts glycemic control in DM. Methods: Patients with DM and prostate cancer newly diagnosed from 2007 to 2014 were identified from the institutional cancer registry and matched to patients with prostate cancer but no DM according to age and year of prostate cancer diagnosis. Results: The study included 276 cases and 276 controls; the mean age was 72 years, most (93%) were white, the most common Gleason score (52%) was 7, and the majority (56%) were tumor stage II. Patients with DM had a higher mean body mass index (P = .03). Alcohol use and performance status differed by group (P<.001), but the 2 groups otherwise were not significantly different. Among those with DM, the mean hemoglobin A1c (HbA1c) was 6.7%. In Kaplan-Meier survival analysis (median followup time, 43.7 months), the 5-year OS rates were estimated at 88% and 93% for patients with and without DM, respectively (hazard ratio, 1.64; 95% confidence interval, 0.77- 3.46; P = .20). Mean glucose among patients with DM was significantly higher (P<.001) compared with non- DM patients, but mean HbA1c and glucose values did not change significantly over 1 year (P≥.13). Conclusion: DM did not adversely impact survival in patients with prostate cancer. In addition, prostate cancer and its treatment did not affect glycemic control. Patients and their providers can be reassured that the concurrent diagnoses do not adversely interact to worsen short-term outcomes.