Diabetes mellitus is associated with short prostate-specific antigen doubling time after radical prostatectomy.

OBJECTIVE: To investigate whether diabetes mellitus (DM) was associated with postoperative outcomes, including prostate-specific antigen doubling time, among men who underwent radical prostatectomy (RP) for clinically localized prostate cancer (PCa).
METHODS: Data of 661 patients who underwent radical prostatectomy for node-negative prostate cancer and were followed up for ≥3 years postoperatively at our institution were analyzed. Associations between diabetes mellitus at surgery and outcomes following radical prostatectomy, such as biochemical recurrence-free survival and prostate-specific antigen doubling time, were examined. Aggressive recurrence was defined as biochemical recurrence with prostate-specific antigen doubling time <9 months.
RESULTS: Of the 661 total subjects, DM (n = 67, 10.1 %) and non-DM group (n = 594, 89.9 %) showed no significant differences in various clinicopathologic parameters including age and PSA. DM group had lower postoperative biochemical recurrence-free survival than non-DM group, with observed difference approaching statistical significance (log-rank, p = 0.077). On multivariate analysis, DM at surgery was significantly associated with aggressive recurrence following RP (p = 0.048). Pathologic Gleason score (p = 0.008) and seminal vesicle invasion (p = 0.010) were also significantly associated with aggressive recurrence on multivariate analysis.
CONCLUSION: Our results show that pre-existing DM in men with PCa is associated with more aggressive recurrence, suggesting that DM may affect disease progression following RP. Further investigation would be needed to elucidate exact biologic interaction between DM and PCa and also assess causal relationships that potentially could be modified to improve long-term outcome in patients with the two diseases.