Preoperative Glycemic Control Status as a Significant Predictor of Biochemical Recurrence in Prostate Cancer Patients after Radical Prostatectomy

Background: The effect of diabetes mellitus (DM) on prostate cancer (PCa) outcome remains controversial. Thus, we investigated the association of DM history, glycemic control, and metformin use with oncologic outcomes after radical prostatectomy (RP). Methods: We reviewed the records of 746 contemporary patients who had hemoglobin A1c (HbA1c) measured within the 6 months preceding RP. The associations between clinical variables and risk of adverse pathological features and biochemical recurrence (BCR) were tested using a multivariate logistic regression and multiple Cox-proportional hazards model, respectively. BCR was defined as prostatic specific antigen (PSA) > 0.2 ng/mL in 2 consecutive tests. Results: There were no significant differences in the rates of adverse pathologic features and BCR-free survival between patients with (n = 209) and without (n = 537) a history of DM diagnosis (all p > 0.05). In multivariate analyses, high HbA1c level (≥ 6.5%) was significantly related with high pathologic Gleason score (≥ 4+3; odds ratio [OR] 1.704, p = 0.019) and BCR-free survival (OR 1.853, p = 0.007). Metformin use was not associated with BCR-free survival (OR 0.662, p = 0.125). Conclusions: Poor glycemic control was significantly associated with BCR after RP. Meanwhile, metformin use was not associated with biochemical outcome after RP. Further investigation would be needed to identify exact mechanism underlying the impact of glycemic control on PCa treatment outcome.