Impact of PI-RADS During Active Surveillance for Prostate Cancer on Pathological Findings at Repeat Biopsy

This study aimed to determine whether lesion visibility on magnetic resonance imaging (MRI) predicts rebiopsy outcomes during active surveillance for prostate cancer.

We retrospectively analyzed data from 111 patients enrolled in the Prostate Cancer Research International Active Surveillance study (Japan) at Kagawa University (January 2010-February 2025). After excluding 19 patients who discontinued active surveillance within one year, 92 patients were included in the analysis. MRI findings were classified as visible [Prostate Imaging Reporting and Data System (PI-RADS) score ≥3] or invisible (score ≤2). We assessed the association between visibility and rebiopsy outcomes, defined as reclassification progression beyond active surveillance criteria or no cancer.

MRI was performed at diagnosis in 32.6% (n=32) of patients, at one year in 37.0% (n=34), and at four years in 47.7% (n=21). Lesion visibility at diagnosis was not associated with continuation of active surveillance compared with invisibility [median 43 months, 95% confidence interval (12-not available) vs. not available (17-not available), p=0.404]. However, at the 1-year rebiopsy, reclassification occurred significantly more frequently in patients with visible lesions than in those with invisible lesions (42.1% vs. 7.1%, p=0.047). Conversely, no cancer was more common in patients with invisible lesions (50.0% vs. 10.5%, p=0.019).

At one year, a PI-RADS score ≥3 was associated with a higher risk of reclassification, whereas a score ≤2 was associated with a greater likelihood of no cancer on rebiopsy. These findings highlight the prognostic value of MRI in guiding active surveillance.