To evaluate the influence of 5-ARIs on the performance of MRI for detection of Gleason grade group (GG) ≥2 prostate cancer, and on apparent diffusion coefficient (ADC) maps.
This single center, retrospective study included men who had MRI for initial detection or active surveillance of prostate cancer. The study group included 59 men who used for 5-ARI for ≥12 months, and the control group included 59 men who were matched for both MRI indication and biopsy results. DeLong’s test was used to compare the area under the receiver operating curve (AUC) for detection of GG ≥2 cancer between the groups. Wilcoxon rank sum test was used for comparison of lesions ADC metrics between the groups.
MRI accuracy in the study group (AUC=0.778) was not significantly different compared to the control group (AUC=0.821) (95% confidence interval for difference: 0.22, 0.13; p=0.636). In the control group, all ADC metrics were lower in lesions with GG ≥2 cancer on biopsy than in those with GG 1 cancer or negative results (p=0.001-0.01). In the study group, this difference was significant only when the mean ADC of the lesions was normalized by the ADC of urine (p=0.044).
Long-term exposure to 5-ARIs does not seem to impair the detection of significant cancer on MRI but may affect the ability of ADC metrics to discriminate between lesions that harbor significant cancer and those that harbor insignificant cancer or benign tissue.

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