A numerical formula called the absolute percentage pattern 4/5 (APP4) combining risk factors, including Gleason grade, PSA, and digital rectal examination, is being used to select patients whose intermediate risk prostate cancer can safely be followed with active surveillance.

A research study using APP4 was reported at the 2025 ASCO Genitourinary Cancers Symposium in San Francisco. First author Ruben Del Castillo, MD, a radiation oncologist from the Sunnybrook Health Sciences Centre in Toronto, Canada, shared the details.