Natural history of histologically benign PIRADS 4–5 lesions in multiparametric MRI: Real‐life experience in an academic center

Abstract

AbstractIntroductionThe follow‐up findings of patients who underwent prostate biopsy for prostate image reporting and data system (PIRADS) 4 or 5 multiparametric magnetic resonance imaging (mpMRI) findings and had benign histology were retrospectively reviewed.MethodsThere were 190 biopsy‐naive patients. Patients with at least 12 months of follow‐up between 2012 and 2023 were evaluated. All MRIs were interpreted by two very experienced uroradiologists. Of the patients, 125 had either cognitive or software fusion MR‐targeted biopsies with 4 + 8/10 cores. The remaining 65 patients had in‐bore biopsies with 4–5 cores. Prostate‐specific antigen (PSA) levels below 4 ng/mL were defined as PSA regression following biopsy. PIRADS 1–3 lesions on new MRI images were classified as MRI regression.ResultsMedian patient age and PSA were 62 (39–82) years and six (0.4–33) ng/mL, respectively, at the initial work‐up. During a median follow‐up period of 44 months, 37 (19.4%) patients were lost to follow‐up. Of the remaining 153 patients, 82 (53.6%) had persistently high PSA. Among them, 72 (87.8%) had repeat mpMRI within 6–24 months which showed regressive findings (PIRADS 1–3) in 53 patients (73.6%) and PIRADS 4–5 index lesion persistence in 19 cases (26.4%). The latter group was recommended to have rebiopsy. Of these 19 patients, 16 underwent MRI‐targeted rebiopsy. Prostate cancer was diagnosed in six (37.5%) patients and of these four (25%) were clinically significant (>Grade Group 1). Totally, clinically significant prostate cancer was detected in 4/153 (2.6%) patients followed up.ConclusionPatients should be warned against the relative relaxing effect of a negative biopsy after identification of PIRADS 4–5 index lesion. While PSA decrease was observed in many patients during follow‐up, persistent MRI findings were present in nearly a quarter of patients with persistently high PSA. A rebiopsy is warranted in these patients, with significant prostate cancer diagnosed in a quarter of patients with rebiopsy.