The 4kscore Test Predicts High Grade Prostate Cancer on Biopsy at Psa Levels < 4ng/ml

Introduction: The clinical value of PSA for prostate cancer early detection has been questioned primarily due to its poor specificity for clinically relevant disease, namely high grade prostate cancer. This is especially true at PSA levels lower than 4 ng/mL, generally considered to be within the normal range. However, PSA values between 1.54 ng/mL have been referred to as the PSA Danger Zone because the risk of prostate cancer in men with PSA within this range is 15-18x higher compared to that in men with PSA< 1.5ng/mL. Moreover, a surprising number of otherwise healthy men with PSA less than 4 ng/mL are at risk for prostate cancer metastases and death up to 20 years later. The 4Kscore Test has been validated to predict an individual man’s risk of high grade cancer on biopsy, with an area under the curve of 0.82. This test incorporates: Total PSA (tPSA), Free PSA, Intact PSA, human Kallikrein-2, age, digital rectal examination findings, and previous biopsy information into an algorithm. The objective of this study was to see if the 4Kscore Test can predict high grade (Gleason ≥ 7) prostate cancer in men with a tPSA < 4 ng/mL.