This study explores the characteristics of PI-RADS 5 prostate lesions that could help identify cases with low or no cancer risk, aiming to reduce unnecessary biopsies. PI-RADS 5 lesions are typically considered highly predictive for significant prostate cancer (PCa), but around 18% yield benign results upon biopsy. By retrospectively analyzing 838 PI-RADS 5 lesions from 646 patients (collected from May 2014 to October 2022), researchers examined clinical and MRI characteristics to assess factors predicting non-cancerous or low-grade pathology. The lesions were categorized into benign, Gleason Grade Group 1 (GGG1), and Gleason Grade Group 2 or higher (GGG2+). Key protective factors against higher-grade cancer (GGG2+) included inflammation on pathology, lesions located in the transition zone (TZ) versus the peripheral zone (PZ), prior negative biopsy, and being on active surveillance (AS).
Data analysis showed that inflammation on pathology had a strong protective association against both GGG1 (OR 0.141; p<0.001) and GGG2+ (OR 0.037; p<0.001) cancer, making it a significant indicator for low cancer likelihood. Additionally, TZ lesions, a history of negative biopsy, and AS showed lower odds of GGG2+ cancer, with negative predictive values (NPVs) of 81%, 70%, and 80%, respectively. Higher odds of GGG2+ cancer were associated with older age and elevated PSA levels. Among the 23 patients with inflammation on biopsy, only one had GGG1 or higher-grade disease, and 9 had known pre-biopsy prostatitis, indicating inflammation’s potential as a low-risk marker.
This research suggests that inflammation and specific pre-biopsy characteristics may help guide biopsy decisions, potentially sparing some men from low-yield procedures. Continued development of pre-biopsy markers for inflammation could further refine risk stratification.
