Metformin delays progression of prostate cancer: a retrospective study on 192 cases

Abstract

Objective To investigate the effects of preoperative use of metformin on the biochemical recurrence (BR) in the patients with localized prostate cancer after radical prostatectomy (RP) and on the occurrence of castration resistance in patients with bone metastasis after RP. Methods A retrospective analysis was performed on 192 patients diagnosed with localized prostate cancer and undergoing RP in our hospital from January 2008 to April 2020, including 31 cases of postoperative BR and 161 cases of bone metastatic prostate cancer. The patients were further divided into observation group (metformin with/without androgen deprivation therapy) and control group (no treatment/androgen deprivation therapy alone), based on whether they were preoperatively treated with metformin or not. The baseline characteristics of the 2 groups were collected and compared, including age, initial prostate specific antigen (PSA) level, PSA level at BR, pathological T stage, and Gleason score. The time to BR or to progression to castration-resistant prostate cancer (CRPC), PSA doubling time (PSADT), and PSA minimum were calculated and analyzed between the 2 groups. Results For the postoperative BR patients, the median time to BR (22.73 vs 10.73 months, P < 0.05) and mean PSADT (4.69 vs 4.30 months, P < 0.05) were significantly longer in the observation group than the control group. For the patients with bone metastatic prostate cancer, the observation group had obviously longer median time to CRPC (22.35 vs 16.05 months, P < 0.05) and median PSADT (4.50 vs 2.60 months, P < 0.05) when compared with the control group. But no such difference was seen in PSA minimum after treatment between them. Conclusion Metformin can effectively delay the progression of localized prostate cancer to BR after RP, and the progression of bone metastatic prostate cancer to CRPC.

Keywords

• metformin
• prostate cancer
• biochemical recurrence
• bone metastasis