Pathology outcomes of PI-RADS category 4 lesions in the peripheral zone: impact of MRI signal features and lesion size

BackgroundPeripheral zone (PZ) PI-RADS category 4 includes lesions with diverse pathological outcomes, leading to varying prostate cancer (PCa) detection rates between pure category 4 (pCategory-4) and upgraded category 4 (Category-3+1) PZ lesions, as well as different lesion sizes.PurposeTo compare PCa detection rates for pCategory-4 and Category-3+1, considering lesion size.Material and MethodsThis retrospective study included 293 participants with PI-RADS V2.1 category-4 PZ lesions, who underwent MRI-targeted biopsy between 2012 and 2021. Overall and clinically significant PCa (csPCa) detection rates for pCategory-4 and Category-3+1 lesions were compared using Pearson's chi-square (χ²) test. In addition, PCa detection rates were analyzed by lesion size (1-5 mm, 5-10 mm, 10-15 mm, and >15 mm) using Spearman's test. Logistic regression analysis included age, PSA, PSA density, lesion volume, and size/scale for PZ lesions.ResultscsPCa detection rates were 60.4% for pCategory-4 and 25.8% for Category-3+1, while overall PCa detection rates were 69.4% and 36.2%, respectively. pCategory-4 showed higher cancer detection rates than Category-3+1 (overall PCa: χ² = 22.34; <i>P</i> <0.0001, csPCa: χ² = 21.88; <i>P</i> <0.001). Larger lesions (>5 mm) were more likely to harbor PCa, with significant differences in detection rates observed for pCategory-4 and Category-3+1 (overall PCa: χ² = 20.05; <i>P</i> <0.001).ConclusionpCategory-4 lesions have significantly higher PCa detection rates compared to Category-3+1. Larger lesion size is associated with increased PCa detection in pCategory-4 lesions but not in Category-3+1.