The Impact of Dutasteride Treatment on Subsequent Multiparametric Prostate Magnetic Resonance Imaging Sequences and...

The effect of dutasteride on benign prostate lesions and Prostate Imaging-Reporting and Data System (PI-RADS) scores remains uncertain. We evaluated its impact on pathologically benign transition zone (TZ) PI-RADS 3 lesions.

We reviewed 3104 multiparametric magnetic resonance imaging (mp-MRI) scans (March 2019-November 2023). Patients undergoing MRI-ultrasound fusion biopsy for PI-RADS 3 lesions with ≥ 2 mp-MRI scans were evaluated. After exclusions, dutasteride users formed the study group (n = 24) and non-users the control group (n = 60). Demographics, prostate-specific antigen (PSA), PSA density, prostate volume, pre-biopsy/control mp-MRI characteristics and PI-RADS scores were compared.

Mean dutasteride use was 12.1 months. Lesion size decreased in both groups, more so in the study group. Within the study group, mean lesion apparent diffusion coefficient (ADC) increased and the T2-weighted (T2WI) lesion/transition-zone ROI ratio decreased whereas neither changed in controls; on between-group comparison, the ADC increase was significantly greater but the T2WI ratio change was not. Complete lesion disappearance was significantly more frequent in the study group and remained an independent predictor on multivariable analysis; PI-RADS up/downgrading and new-lesion rates were similar.

In benign TZ PI-RADS 3 lesions, dutasteride did not affect PI-RADS up-/downgrading of persistent lesions but was independently associated with a higher rate of complete lesion disappearance, a greater reduction in lesion size, and a greater increase in lesion ADC; the T2WI ratio change did not differ between groups. Because these changes can make benign lesions appear less conspicuous, dutasteride use should be conveyed to the radiologist interpreting follow-up mp-MRI.