Retrospective cohort study reveals regression or stability in 81% of PI-RADS 3 lesions on serial mpMRI, suggesting interval imaging surveillance is a safe alternative to immediate biopsy.
Key Points
To evaluate the radiologic trajectory of indeterminate PI-RADS 3 prostate lesions on serial follow-up mpMRI and correlate imaging changes with biopsy pathology.
Retrospective cohort study of 166 men with at least one PI-RADS 3 lesion on initial mpMRI who underwent at least one serial follow-up mpMRI without intervening therapy.
Lesions were categorized by zonal location and classified at follow-up as regressed (PI-RADS ≤ 2), stable (PI-RADS 3), or progressed (PI-RADS 4–5).
Histopathologic outcomes from MRI-targeted biopsies were analyzed in a subset of patients (n = 64).
On follow-up mpMRI, 52% of lesions regressed, 29% remained stable, and 19% progressed; progression was significantly higher in peripheral-zone lesions (25%) than transition-zone lesions (6%).
Among biopsied lesions (n = 64), 44% were benign, 47% were ISUP 1, 6% had high-grade PIN/ASAP, and 3% harbored clinically significant prostate cancer (ISUP ≥ 2), all occurring in radiologically progressed lesions.
Lesions with imaging progression were significantly more likely to yield cancer on biopsy than stable or regressed lesions (83% vs 40%; p = 0.037).