ORLANDO, Fla.—A new tool called the 4Kscore could help avoid unnecessary prostate biopsies by enabling clinicians to more accurately discriminate which patients are likely to have high-grade prostate cancer (PCa) found at biopsy, according to a new study presented at the 2015 Genitourinary Cancers Symposium.
The new study is the first prospective evaluation of the 4Kscore for detecting high-grade PCa (Gleason score 7 or higher) among men referred for prostate biopsy in the United States. It enrolled 1,012 men scheduled for prostate biopsy at 26 U.S. centers.
The 4Kscore combines the results of blood assays of 4 kallikrein proteins (total, free, and intact PSA and hK2) with clinical information (such as age, digital rectal examination findings, prior biopsy status, and family history), into an algorithm. “It actually provides you with a personalized risk prediction,” said lead author Sanoj Punnen, MD, of the University of Miami Miller School of Medicine, who presented study findings.
Biopsies revealed high-grade PCa in 231 men (23%). The 4Kscore showed excellent calibration, with the predicted probability of high-grade PCa being similar to what was observed, Dr. Punnen’s group reported. In fact, the 4Kscore demonstrated greater discrimination than the widely used Prostate Cancer Prevention Trial Risk Calculator.
“This type of information I think is very helpful to both the patient and the clinician for informed decision making and shared decision making,” Dr. Punnen told attendees.
The number of unnecessary biopsies that could be avoided varied depending on the threshold used for biopsy. If the threshold for biopsy was a 6% or greater probability that high-grade PCa would be found, 30% of biopsies would be avoided and only 1.3% of Gleason 3+4 or higher cancers would be missed. If the threshold was 9% or higher, 43% of biopsies would have been avoided and only 2.4% of high-grade cancers would be missed, according to investigators.
If the threshold was 15%, nearly 60% of unnecessary biopsies could have been avoided.