What is the 4K biomarker?
The 4Kscore test combines the test results of four different proteins (prostate-specific kallikreins) in the blood together with clinical information in an algorithm that calculates an individual patient's percentage risk of having an aggressive form of prostate cancer.
What does the 4Kscore
The 4Kscore test relies on the measurement of four prostate-specific kallikreins in the blood: total PSA (prostate-specific antigen), free PSA, intact PSA, and human kallikrein 2 (hK2).
What is the role of the 4Kscore
test in prostate cancer screening?
The 4Kscore test helps clarify the biopsy decision-making process by determining a patient-specific probability for finding aggressive, Gleason score 7 or higher prostate cancer upon biopsy. These are the aggressive prostate cancers that always require medical treatment or intervention. The blood test results are combined in an algorithm with patient age, digital rectal exam findings (nodules vs. no nodules), and prior negative biopsy (yes or no) to give physicians a personalized score for individual patients. The 4Kscore test predicts the risk percent score from less than 1% to greater than 95% of a man having aggressive cancer in a prospective biopsy.
How does the 4Kscore
test minimize unnecessary prostate biopsies?
Several studies have demonstrated the ability of the 4Kscore test in predicting the detection of Gleason 7 or higher prostate cancer. One study involved 1,012 men in the United States.
The 4Kscore test has undergone extensive clinical research and laboratory test validation. Based on the results of clinical studies, as many as 30%-58% of biopsies are avoidable using the 4Kscore test. This is based on the fact that only about 20% of men who undergo prostate biopsy will have a 7 or higher Gleason score. The remainder will have either a negative biopsy or a cancer with a score of Gleason 6, which currently is often managed with active surveillance.
Prostate Cancer Screening Test
Biomarkers have been developed to help define the probability of prostate cancer prior to proceeding to biopsy. The goals of the biomarker tests are to decrease the risk of unnecessary biopsies and increase the likelihood of cancer detection without missing a significant number of prostate cancers. The biomarker tests may be most useful in men with PSA levels between 3 and 10 ng/mL. Currently, the NCCN recommends consideration of percent free PSA (%fPSA), Prostate Health Index (PHI), and 4Kscore in patients with PSA levels > 3 ng/mL who have not had an initial prostate biopsy. For individuals who have had at least one negative prostate biopsy but who are thought to be at higher risk for prostate cancer (increasing PSA), the NCCN recommends %fPSA, PHI, 4Kscore, PCA3, and ConfirmMDx. Select MDx is a biomarker that can be obtained prior to initial biopsy and after negative biopsy. At present, no test has been established to be superior to another. Prior to having such studies done, it is advisable to ensure that your insurance company covers these tests.
What is the cost of the 4Kscore test?
The cost of the 4Kscore test is listed as $760.00. If individuals have questions regarding the cost of the test, there is a toll-free number one can call: 1-855-452-4554.
What is the PHI (prostate health index test)?
The PHI is a PSA-based test; however, it uses a mathematical formula that combines total PSA, free PSA, and (-2)proPSA. The PHI has been demonstrated to outperform each of the component tests (total PSA, free PSA, and [-2]proPSA individually) of estimating the presence of overall and high grade prostate cancer on biopsy.
Is one test, the PHI or 4Kscore, better than the other?
There are no published studies comparing these two tests. The two tests provide somewhat different information and can be considered to be complimentary. PHI predicts the risk of having prostate cancer, whereas the 4Kscore predicts the risk of having high-risk prostate cancer.
Medically Reviewed on 6/7/2018
Loeb, S., and W. Catalona. "The prostate health index: a new test for the detection of prostate cancer." Therapeutic Advances in Urology 6.2 (2014): 74-77.
Parekh, D.J., et al. "A multi-institutional prospective trial in the United States confirms that the 4Kscore accurately identifies men with high grade prostate cancer." European Urology 68.3 Sept. 2015: 464-470.
Punnen, S., et al. "Finding the Wolf in Sheep's Clothing: The 4Kscore Is a Novel Blood Test That Can Accurately Identify the Risk of Aggressive Prostate Cancer." Reviews in Urology 17.1 (2015): 3-13.