J Cancer 2012; 3:122-128. doi:10.7150/jca.4123 This volume

Research Paper

Prostate Cancers Detected During 5α-Reductase Inhibitor Use Are Smaller, De-Differentiated, But Confined when Compared To Controls

Fred Lee1,2 ✉, Robert A. Badalament1,2, Chen Hu3, Ingrid Bousho1, Alex Tsodikov3

1. Rochester Urology, PC, Rochester Hills, MI
2. Crittenton Hospital, Rochester Hills, MI
3. Department of Biostatistics and School of Public Health, University of Michigan, Ann Arbor, MI

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Lee F, Badalament RA, Hu C, Bousho I, Tsodikov A. Prostate Cancers Detected During 5α-Reductase Inhibitor Use Are Smaller, De-Differentiated, But Confined when Compared To Controls. J Cancer 2012; 3:122-128. doi:10.7150/jca.4123. Available from https://www.jcancer.org/v03p0122.htm

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Rationale: To compare cancers detected during use of 5α-reductase inhibitors (5αRI) with cancers detected in untreated controls stratified for tumor size.

Methods: Prostate biopsies were performed on 235 consecutive patients “for cause” (elevated or rising PSA, positive digital rectal examination, or focal hypoechoic lesion). Fifty patients were excluded for a prior diagnosis of cancer, leaving 185 as the study group (5αRI=41, control=144). Patients in the 5αRI group had been treated for a mean of 3.5 years. Cancer was ultimately diagnosed in 114/185 patients.

Results: Cancer was diagnosed in 31/41 (76%) of patients treated with 5αRI and 83/144 (58%) of the control group (p=0.04). Control tumors were larger (14.3 mm) than those in 5αRI treated patients (9.4 mm, p=0.0007). No differences in mean PSA or PSA kinetics were detected between groups. For tumors less than 1.0 cm, the proportion of high grade cancers (Gleason 7-10 and Gleason 4+3-10) was higher in 5αRI subjects than in controls (p<0.05). Fewer 5αRI patients had proven extracapsular extension than controls, but this difference did not reach statistical significance (p=0.13). Normal DNA ploidy was more likely to be diagnosed in the 5αRI group versus controls, but this difference was not statistically significant (81% vs. 65%, p=0.14).

Conclusions: Cancers diagnosed in patients presenting “for cause” treated with 5αRI drugs are more likely to be de-differentiated compared to controls. However, these tumors are also smaller and less likely to have extracapsular extension and abnormal DNA ploidy than controls.

Keywords: Prostate Cancer, Benign Prostatic Hyperplasia, 5α-reductase inhibitors, Gleason score, DNA ploidy, cancer staging.