A high prostate-specific antigen (PSA) level doesn’t necessarily mean a man has prostate cancer, but it will usually lead to a referral for a prostate biopsy. Yet fewer than half of prostate biopsies detect cancer, which means many men needlessly endure an exam that can cause anxiety and pain, as well as bleeding and infection, in some cases. New tests are available that may allow some men with elevated PSA or a suspicious digital rectal exam to hold off on a biopsy. They include:
The Prostate Health Index (phi). This blood test calculates a man’s risk for having prostate cancer by measuring total PSA, free PSA (which can help determine whether PSA is elevated because of cancer or other causes), and p2PSA, a form of PSA that is associated with malignant prostate tumors. A 2017 study found that phi scores influenced the treatment plans recommended by doctors caring for men with PSA levels between 4 ng/mL and 10 ng/mL in 73 percent of cases; low scores led them to recommend deferring biopsies, while higher scores persuaded them that a biopsy was necessary.
4Kscore. This test also measures total and free PSA, as well as intact PSA (a form of free PSA associated with prostate cancer) and a related protein called human kallikrein 2; it factors in other elements, such as age and the digital rectal exam result, too. A 2015 study conducted at several clinics found that 4Kscore results influenced the decision making of nearly nine out of 10 men and reduced biopsies by 65 percent.
Other assays. The number of tests that permit improved, more selective detection of clinically significant cancer is on the rise. Available tests include Mi-Prostate Score (MiPS), ExoDx Prostate (IntelliScore), and SelectMDx, and others are in development.
Multiparametric MRI. A growing number of urologists are performing pre-biopsy MRIs, which serve two purposes. For one, an MRI can rule out some men as biopsy candidates, because the imaging exam can reveal whether they harbor a prostate tumor that requires prompt treatment.
Furthermore, if an MRI does reveal the presence of cancer, a doctor can use that image to target biopsy needles to a specific region on the gland, which minimizes the risk of a biopsy missing high-grade cancer. An imaging method called multi-parametric MRI (mp-MRI) provides doctors with a view not only of the prostate anatomy, but also cell structure, blood supply, and other data.
In 2017, the PROMIS study showed that mp-MRI could reduce unnecessary biopsies by about one-quarter in men with elevated PSA. In addition, mp-MRI detected 18 percent of potentially lethal tumors that traditional biopsies missed. MRI is also increasingly used after a prostate biopsy detects cancer in order to learn more about the size and nature of the tumor or to rule out the possibility that a biopsy missed a potentially dangerous malignancy before a man chooses active surveillance.
It’s important to remember that there are limited data on some of these tests, which have not been compared head to head, so it’s not clear which approach is best. Insurance often covers the cost, but you should check with your provider first.
And keep in mind that the results of these tests offer additional data but need to be considered in addition to your physician’s clinical judgment when you decide what medical choice is right for you.