The holy grail of a single test to diagnose prostate cancer is not available at this time. The PSA test or prostate specific antigen is a blood test that measures a protein produced in the prostate gland. It is elevated in men with prostate cancer. However, it is also elevated in men with prostate gland infections (prostatitis) and even men with large prostate glands. Now there are new tests that are used to detect and to monitor prostate cancer. Unfortunately, there are few published studies on these new tests and none of tests have a long-term track record of their application to real patients in the real world. I have, therefore, tried to summarize the latest prostate cancer tests and hopefully this will answer some of your questions.
An elevated screening PSA level often leads to a prostate gland biopsy. This isn’t to be taken likely although it is a simple procedure performed in the doctor’s office with minimal pain and discomfort. There are now two tests to more accurately identify appropriate biopsy candidates.
Prostate health index (Phi test)
This blood assay measures total PSA, free PSAT and precursor of PSA or pro-PSA. Research suggest that pro-PSA levels are a better indicator of prostate cancer than total or free PSA levels. Men with elevated pro-PSA eves are at a high risk for having an aggressive form of prostate caner. The test is indicated in men who have an elevated total PSA (greater than 4.0ng\ml and less than 10.0ng\ml). This test indicates the probability of a biopsy detecting prostate cancer. A low score suggests low likelihood of prostate cancer and the patient may decide to defer a biopsy and repeat the test in 6 months.
This test measures total PSA, free PSA and intact PSA plus an enzyme, kallikrein, which is elevated in men with prostate cancer. The 4K score, like the Phi test, provides a number to calculate the risk of prostate cancer in a man with an elevated PSA level.
Testing following a negative prostate biopsy
Some biopsies produce an inclusive result. Others may be negative even in men with elevated PSA or other risk factors like age, family history, or African-American descent. Often the biopsies are repeated although only 10-36% of second biopsies detect prostate cancer. The following tests can be helpful to determine the need for a repeat prostate biopsy.
This is a urine test that detects the presence of a gene called prostate antigen 3 or PCA3. This PCA3 gene appears in 95% of men with prostate cancer, but not in men with benign enlargement of the prostate gland. Low scores indicate a decreased likelihood of a positive biopsy. This test is used in men who have had one or more negative prostate biopsies, but a suspicion of prostate cancer is still present.
This test was developed at Johns Hopkins and analyzes DNA methylation in an area of a prostate biopsy. A biopsy only samples a small amount of tissue making it possible to miss a cancer that is adjacent to the biopsy site. The Confirm MDx monitors an area much larger than biopsy site and checking for the methylation field affect. The test uses the previous biopsy specimen and provides either a positive or negative interpretation. A positive finding suggest that prostate cancer is present and may require another biopsy targeted to the area of the methylation field affect.
Positive biopsy and whether to proceed with treatment
Many men with a positive prostate biopsy for prostate cancer have low risk cancers that are unlikely to spread to other organs or to cause death from prostate cancer. For some of these men active surveillance may be a reasonable alternative to immediate treatment. Until recently, there were no tests or studies that could distinguish between indolent or slow growing cancers and aggressive tumors that are likely to spread or likely to increase the likelihood of death from prostate cancer.
This test uses a sample of the tumor obtained from a biopsy and measures how rapidly cells are dividing in order to determine whether the tumor is more or less likely to be aggressive. Higher Prolaris scores places the man at a greater risk of dying from prostate cancer and that the man should consider proceeding to some form of treatment.
This test uses biopsy tissue to determine the presence of two genetic biomarkers for prostate cancer, TMPRSS2:ERG and PTEM. By searching for these two markers, the test provides an analysis of prostate cancer aggressiveness and the man’s long-term prognosis.
This test examines the interaction of 17 genes in a biopsy specimen. The score is graded from 0-100%. A low score suggests that the tumor is less likely to grow and spread and that treatment can be delayed and that the patient can be offered active surveillance as a form of management where the patient get a physical exam, a PSA test, and often a repeat biopsy in 6-12 months.
Treatment after surgical removal of your prostate gland
Some men after surgical removal of the prostate gland may benefit from additional treatments such as radiation or hormonal therapy. The Prolaris test can be helpful in determining the need for additional therapy.
How much do these tests cost?
Unfortunately, not all of these tests are covered by your insurance companies. Therefore, you may need to pay out of pocket for some or even all of the costs of these tests. Before having one of these tests, I suggest you check with your insurer first. Also, our office can check with the test’s manufacturer and let you know their coverage policy and what would be your out of pocket expenses.