This study investigates pre-biopsy factors that could help predict which PI-RADS 5 prostate lesions may be benign or clinically insignificant, potentially sparing some patients from low-yield biopsies. While PI-RADS 5 lesions generally have a high predictive value for clinically significant prostate cancer (PCa), up to 18% are benign. Researchers reviewed 838 PI-RADS 5 lesions from 646 patients between May 2014 and October 2022, categorizing biopsy results by Gleason grade groups (GGG): benign, GGG1, and GGG2+. They analyzed clinical factors associated with each group to identify characteristics that might reduce the likelihood of finding aggressive cancer. Results showed that 13% of PI-RADS 5 lesions were cancer-free, 18% were GGG1, and 68% were GGG2+. Notably, inflammation in biopsy samples was significantly protective against both GGG1 (OR 0.141; p<0.001) and GGG2+ (OR 0.037; p<0.001) cancers. Additional factors protective against GGG2+ included having transitional zone (TZ) lesions (OR 0.431; p=0.003), prior negative biopsy (OR 0.250; p<0.001), and being on active surveillance (AS) (OR 0.254; p<0.001). Patients with multiple PI-RADS 5 lesions also had reduced odds of aggressive cancer, particularly with 3-5 lesions (OR range 0.052 to 0.377). Older age and elevated PSA levels increased the likelihood of finding GGG2+ disease.
Protective characteristics, like TZ lesions (81% NPV) and multiple PI-RADS 5 lesions (86% NPV), may help stratify risk but offer only moderate predictive value. Among 23 patients with biopsy-confirmed inflammation, just one had GGG1 or GGG2+ cancer, suggesting that pre-biopsy identification of inflammation could help avoid unnecessary biopsies. These findings suggest that refining pre-biopsy criteria may improve risk assessment for men with PI-RADS 5 lesions.
