Tumor features and survival after radical prostatectomy among antidiabetic drug users.

BACKGROUND: To evaluate the association between use of metformin and other antidiabetic drugs with tumor characteristics and survival in surgically managed prostate cancer (PCa) patients. METHODS: The study population included 1314 men who underwent radical prostatectomy at the Tampere University Hospital during 1995-2009. Causes of deaths were collected from the Finnish Cancer Registry. Individual-level data on medication use during 1995-2009 was obtained from national prescription database. Fasting blood glucose and hemoglobin A1c values during the study period were gathered from hospital district database. Gleason grade and pathological stage were compared by drug use before surgery and separately by metformin usage. Risk of biochemical recurrence, all-cause death and PCa-specific death were calculated using Cox proportional hazard regression with adjustment for age, tumor characteristics, glycemic control and use of other drug groups. RESULTS: High-grade tumors were more common among antidiabetic drug users (P=0.032), including metformin users (P=0.012). Despite this, no difference in PSA levels was observed. Men who had used antidiabetic drugs before surgery had an increased risk of Gleason 7-10 disease (odds ratio (OR) 1.83, 95% confidence interval (CI) 1.04-3.23). The risk of high-grade PCa was higher among metformin users compared with other antidiabetic drug users (OR 3.11, 95% CI 1.16-8.33). During the median follow-up of 8.6 years after surgery, 551 men had biochemical recurrence and 244 died, 32 owing to PCa. Generally, no association with risk of disease recurrence was observed. Risk of death was increased by preoperative use of antidiabetic drugs (hazard ratio 1.81 95% CI 1.03-3.19), but no survival associations for postoperative use of antidiabetic drugs or metformin were observed. CONCLUSION: Diabetic men have more high-grade PCa at lower PSA levels, but that does not have a clear impact on disease-specific survival in the short term even when glycemic control is being considered.

Detection rates of cancer, high grade PIN and atypical lesions suspicious for cancer in the European Randomized Study of Screening for Prostate Cancer.

THE AIM OF THE STUDY: This article presents the incidence of prostate cancer, isolated high grade prostatic intraepithelial neoplasia (PIN) and atypical lesions suspicious for prostate cancer (LSPC) during subsequent screening rounds in the centres of five of the countries participating in the European Randomized Study of Screening for Prostate Cancer (ERSPC). The incidence and predictive value of high grade PIN and LSPC for prostate cancer in subsequent biopsy following these diagnoses were evaluated. PATIENTS AND METHODS: Study group consisted of 56,653 screened men in the ERSPC centres of Finland, Italy, Netherlands, Sweden and Switzerland, who underwent 3-7 screening rounds at 2-4 year interval. Data for prostate cancer were obtained from the ERSPC central database. Data for high grade PIN and LSPC were gathered from each ERSPC centre. Detection rates of subsequent prostate cancer in the first re-biopsy after these diagnoses were determined. RESULTS: The average cancer detection rate was 3.5%, 3.2% and 3.5% for the completed rounds 1, 2 and 3, respectively, in all five centres. Incidence of high grade PIN increased from 1.5% in the first round to 5.0% in the third round, varying among centres in the first round between 0.8% and 7.6%. The cancer detection rate in the first re-biopsy after the diagnosis of high grade PIN was 12.9%. Incidence of LSPC was 2.4%, 2.7%, 2.2% and 2.6% in the first, second, third and fourth round, respectively. The cancer detection rate at the first re-biopsy after the diagnosis of LSPC was in average 33.8%. CONCLUSIONS: Cancer detection rate was stable during the three screening rounds. The wide variation in frequency in particular of high grade PIN among the ERSPC centres suggests a considerable inter-observer variation. The average comparatively low detection rate of isolated high grade PIN in the first screening round may be screening-related, while its consistent increase during three screening rounds could be the consequence of a.o. previous screening and ageing of the population. The observed low risk of prostate cancer after isolated high grade PIN in this screening setting is in line with the current recommendation to abstain from early repeat biopsies after this diagnosis. The association of LSPC with high incidence of prostate cancer in re-biopsies confirms the need for early repeat biopsies and follow-up of these men. The low percentage of LSPC (<3% of biopsies) throughout all rounds is reassuring as it limits the biopsy burden in a screening setting.