The Takeaway First
The newest available blood test, 4Kscore® Test (OPKO Lab, Nashville, TN) is better at detecting potential deadly prostate cancer than a PSA test.
Since the prostate-specific antigen (PSA) test first became available in the early ‘90s, there have been significantly fewer deaths from prostate cancer. However, it also has led to overdiagnosis and overtreatment. As a result, about one million prostate biopsies are done yearly in the U.S. alone, and most of it has been from unnecessary overtreatment of indolent cancer in order to rule out the possibility of death.
Numerous studies from Europe and the U.S. indicate that the 4Kscore could be used to distinguish between the less deadly form of prostate cancer (pathologically indolent, as a doctor calls it) and the more dangerous form of the disease — all while reducing excess biopsies.
If that’s true, I’m a fan.
How does the 4Kscore test work?
The 4Kscore test is a blood test and incorporates a panel of four — buckle your seatbelts — kallikrein protein biomarkers: total PSA, free PSA, intact PSA, and human kallikrein-related peptidase. It looks at these biomarkers as well as other clinical information and provides a percentage risk for high-grade (Gleason score 7 or higher) cancer on biopsy.
In 10 peer-reviewed studies, the four kallikrein biomarkers of the 4Kscore Test have been shown to improve the prediction not only of biopsy accuracy, but also surgical pathology and occurrence of aggressive, metastatic disease.
Instead of a PSA-style range value of normalcy, the 4Kscore result is a percentage with personalized positive predictive value of finding Gleason score ≥ 7 cancer on a subsequent biopsy. This is key because the PSA “normal range” value of 0 to 4.0 ng/ml is extremely inaccurate. I see many patients with a PSA higher than 4.0 without prostate cancer and undergoing excessive prostate biopsies.
How does the 4Kscore compare to the urine PCA3 test?
The PCA3 test looks at a urine sample produced immediately after a vigorous prostatic massage. PCA3 is a gene that expresses genetic material in urine. This material is found only in prostate tumor tissue, not normal prostate tissue.
The problem with the PCA3 test is that the results can be difficult to interpret, partly due to lack of an optimal cutoff for a positive test result. The other issue is that the PCA3 is that there’s not a lot of evidence that it actually helps to detect disease. So, while a reading higher than 35 on a PCA3 test may mean prostate cancer is present, a reading of 100 does not necessarily mean that the cancer is aggressive or deadly. In other words, a higher number does not necessarily mean bad cancer.
Remember: a man is only interested on knowing if he has bad cancer that may eventually kill him – not cancer that’s indolent and non-threatening.
Should I get a 4Kscore test?
No, if you:
- have been diagnosed with prostate cancer
- are taking 5-alpha reductase inhibitors like Finesteride (Proscar) or Dutesteride (Avodart)
- have undergone a prostate procedure within 6 months, e.g., TURP for prostate enlargement
Yes, if you are an otherwise healthy, risk-averse man. The 4Kscore test allows you to gauge your risk and decide, based on reliable, personalized results, whether or not to pursue a biopsy. The level of individualized risk prediction afforded by the 4Kscore test is not only helpful to the patient but also to the urologist (me!), who shares in the patient’s decision making.
My take on the 4Kscore Test for Prostate Cancer
Thumbs up. (Where’s my emoji thumbs-up button?)
Anything that helps to prevent unnecessary procedure and helps the patient make an informed decision is fine by me.
Not only do we now have a test superior to the PSA and even PCA3, but when a biopsy is necessary, we can do a targeted biopsy, which is available in many institutions. This helps to detect only bad cancer cells.
Ankerst DP, Hoefler J, Bock S, et al. Prostate Cancer Prevention Trial risk calculator 2.0 for the prediction of low- vs high-grade prostate cancer. Urology. 2014;83:1362–1367.
Vickers AJ, Gupta A, Savage CJ, et al. A panel of kallikrein marker predicts prostate cancer in a large, population-based cohort followed for 15 years without screening. Cancer Epidemiol Biomarkers Prev. 2011;20:255–261