TY - JOUR
T1 - Effect of metformin on prostate cancer outcomes after radical prostatectomy
AU - Kaushik, Dharam
AU - Karnes, R. Jeffrey
AU - Eisenberg, Manuel S.
AU - Rangel, Laureano J.
AU - Carlson, Rachel E.
AU - Bergstralh, Eric J.
PY - 2014/1
Y1 - 2014/1
N2 - Objective: Recent studies have shown a relative risk reduction in the incidence of prostate cancer in patients taking metformin. However, there are conflicting findings on the effect of metformin on established cases of prostate cancer. In this study we evaluated the effect of metformin on survival and pathologic outcomes in established prostate cancer. Materials and methods: We retrospectively identified 12,052 patients who underwent radical prostatectomy between 1997 and 2010 at Mayo Clinic. Among these, 885 (7.3%) were diabetics, including 323 taking and 562 not taking metformin. Kaplan-Meier method was utilized to calculate rates of biochemical recurrence (BCR), systemic progression (SP), and all-cause mortality (ACM). Cox models were used to estimate the metformin hazard ratio (HR) adjusted for clinical and pathologic variables. Results and conclusions: Median follow-up was 5.1 years. In univariate analysis, metformin HR (95% confidence intervals) was not significant for BCR (1.13 [0.84, 1.52]; P = 0.40), SP (1.37 [0.69, 2.72]; P = 0.37), and ACM (1.32 [0.84, 2.05]; P = 0.23). After adjusting for covariates of interest, the HRs for metformin among diabetics remained nonsignificant for BCR (0.91 [0.67, 1.24]; P = 0.55), SP (0.83 [0.39, 1.74]; P = 0.62); and ACM (1.16 [0.73, 1.86]; P = 0.53). No significant difference was seen between metformin users and nonusers in the final pathologic Gleason score (P = 0.33), stage (P = 0.1), rate of positive surgical margins (P = 0.29), or tumor volume (P = 0.76). Metformin use was not associated with a risk reduction in BCR, SP, or ACM. Besides presenting survival data, our results describing metformin's effect on final pathology are unique.
AB - Objective: Recent studies have shown a relative risk reduction in the incidence of prostate cancer in patients taking metformin. However, there are conflicting findings on the effect of metformin on established cases of prostate cancer. In this study we evaluated the effect of metformin on survival and pathologic outcomes in established prostate cancer. Materials and methods: We retrospectively identified 12,052 patients who underwent radical prostatectomy between 1997 and 2010 at Mayo Clinic. Among these, 885 (7.3%) were diabetics, including 323 taking and 562 not taking metformin. Kaplan-Meier method was utilized to calculate rates of biochemical recurrence (BCR), systemic progression (SP), and all-cause mortality (ACM). Cox models were used to estimate the metformin hazard ratio (HR) adjusted for clinical and pathologic variables. Results and conclusions: Median follow-up was 5.1 years. In univariate analysis, metformin HR (95% confidence intervals) was not significant for BCR (1.13 [0.84, 1.52]; P = 0.40), SP (1.37 [0.69, 2.72]; P = 0.37), and ACM (1.32 [0.84, 2.05]; P = 0.23). After adjusting for covariates of interest, the HRs for metformin among diabetics remained nonsignificant for BCR (0.91 [0.67, 1.24]; P = 0.55), SP (0.83 [0.39, 1.74]; P = 0.62); and ACM (1.16 [0.73, 1.86]; P = 0.53). No significant difference was seen between metformin users and nonusers in the final pathologic Gleason score (P = 0.33), stage (P = 0.1), rate of positive surgical margins (P = 0.29), or tumor volume (P = 0.76). Metformin use was not associated with a risk reduction in BCR, SP, or ACM. Besides presenting survival data, our results describing metformin's effect on final pathology are unique.
KW - Biochemical recurrence
KW - Disease progression
KW - Metformin
KW - Prostate cancer
KW - Prostatectomy
KW - Survival rate
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U2 - 10.1016/j.urolonc.2013.05.005
DO - 10.1016/j.urolonc.2013.05.005
M3 - Article
C2 - 23810664
AN - SCOPUS:84890791760
SN - 1078-1439
VL - 32
SP - 43.e1-43.e7
JO - Urologic Oncology: Seminars and Original Investigations
JF - Urologic Oncology: Seminars and Original Investigations
IS - 1
ER -