5-alpha reductase inhibitors and MRI prostates: actively reducing prostate sizes and ambiguity

Abstract

Background Magnetic resonance imaging (MRI) scans are increasingly first-line investigations for suspected prostate cancer, and essential in the decision for biopsy. 5-alpha reductase inhibitor (5-ARI) use has been shown to reduce prostate size and prostate cancer risk. However, insufficient data exists on how 5-ARI use affects MRI findings and yield of biopsy. This study explores the differences in imaging and prostate cancer diagnoses between patients receiving and not receiving 5-ARI therapy. Methods From 2015 to 2020, we collected retrospective data of consecutive patients undergoing prostate biopsy at one centre. We included patients who were biopsy-naïve, had prior negative biopsies, or on active surveillance for low-grade prostate cancer. Clinical and pathological data was collected, including 5-ARI use, Prostate Imaging Reporting and Data System (PIRADS) classification and biopsy results. Results 351 men underwent saturation biopsy with or without targeted biopsies. 54 (15.3%) had a history of 5-ARI use. On mpMRI, there was no significant difference between the 5ARI and non-5-ARI groups in PIRADS distribution, number of lesions, and lesion location. Significantly fewer cancers were detected in the 5-ARI group (46.3% vs. 68.0%; p < 0.01). There were no significant differences in PIRADS distribution in 5-ARI patients with positive and negative biopsy. Conclusion Our study found significant differences in biochemical, imaging and biopsy characteristics between 5-ARI and non-5-ARI groups. While both groups had similar PIRADS distribution, 5-ARI patients had a lower rate of positive biopsies across all PIRADS categories, which may suggest that the use of 5ARI may confound MRI findings. Further studies on how 5-ARI therapy affects the imaging characteristics of prostate cancer should be performed.

Effect of 5-Alpha Reductase Inhibitors on Magnetic Resonance Imaging and Prostate Cancer Detection

“…This observation was true for the entire population and the selected matched group for analysis. Similar findings have been reported by Kim et al [21] and Wang et al [23]. This contrasts with the expected lower serum PSA levels in 5-ARI users compared with those observed in 5-ARI-naïve men because of the effect of 5-ARI exposure on serum PSA levels.…”

“…Starobinets et al suggested improved discrimination in mpMRI between the areas with tumors and those with benign tissue in the peripheral zone [20]. However, the effect of 5-ARI exposure on the PI-RADS category and its corresponding detection of csPCa and iPCa in men suspected of having PCa has been poorly analyzed [21][22][23].…”