Answers to prostate cancer questions

Confused about the latest guidelines on testing and screening? Here’s what you need to know.

Prostate cancer is the second most common cancer among American men, behind skin cancer. Most men can live long and fruitful lives with the disease if it’s properly managed and treated. Still, new studies and evolving guidelines have made the testing and screening process unclear.

So what are the current procedures for getting checked for possible prostate cancer? And what new options are now available? We asked Dr. Marc Garnick, editor in chief of the 2022 Annual Report on Prostate Diseases from Harvard Health Publishing, to address the questions men commonly ask.

The role of PSA

Is the prostate-specific antigen (PSA) test still the best screening option for men?

A PSA test is still controversial, since the vast majority of studies suggest it’s not associated with better quality of life or lower risk of death from prostate cancer. And the results may not always tell the whole story about whether or not you have prostate cancer. Still, it can provide some helpful information.

The test measures the amount of PSA in your blood. PSA is a protein produced by both cancerous and noncancerous tissue in the prostate. While small amounts of PSA normally circulate in the blood, large amounts could suggest cancer. A PSA number less than 4 nanograms per milliliter [ng/mL] is considered to signify a very low risk for cancer. A score of 4 to 10 ng/mL is the gray area where the risk is higher but not conclusive. A PSA score higher than 10 ng/mL is the most concerning.

In men with a high PSA score, the test is usually repeated for accuracy. For example, PSA levels can temporarily spike if you had sex in the previous 24 to 48 hours. An enlarged prostate, which affects most men over time, can also influence PSA. Depending on your PSA score, your doctor may suggest retesting anywhere from four weeks to six months later to check for rising levels.

A digital rectal examination [DRE] is often given if your score is higher than 4 ng/mL. Here, your doctor feels your prostate for any hardness or irregularities in the tissue, which may indicate cancer. It’s best to discuss the pros and cons of PSA testing with your doctor.

Biopsy guidelines

If my PSA continues to rise, or gets higher than 10 ng/mL, what will my doctor order next? Is it time for a biopsy?

For rising or high numbers, there are a few additional tests that could be offered. One is a test that looks for prostate cancer biomarkers in the urine. The kind of biomarker and the amount can indicate the likelihood that cancer exists and may spread.

Another is a blood test for what is known as free PSA. PSA circulates in the blood in two forms — either bound to other proteins, or unbound, also called free. A regular PSA test measures both bound and unbound PSA. The free PSA blood test gets reported as a percent of the total PSA.

A lower percentage suggests a higher risk of cancer. For example, cancer is more likely if a free PSA level is 15% or lower and less likely if it’s higher than 25%. Depending on the results of these tests, your current PSA score, and the findings of a DRE, your doctor may suggest a biopsy to analyze prostate tissue samples for cancer.

However, before a biopsy, you may get a prostate MRI scan. This helps determine the size and location of tumors for a more targeted biopsy with the possibility of having fewer samples taken. Still, during the first biopsy, many doctors will recommend taking biopsies from the entire prostate gland in addition to the abnormal areas suggested by the scan.

Also, keep in mind that even if an MRI scan doesn’t suggest cancer, your doctor may suggest a biopsy depending on the results of the other tests.

New technologies

Are there new diagnostic tests available?

There are two new FDA-approved imaging technologies — the Axumin and gallium-68 PSMA-11 scans. Both are game changers, as they can help identify previously undetectable cancer that even MRI can’t always pick up.

Axumin is the trade name for fluciclovine F 18, a radioactive agent that is injected into your body. You then undergo a scan with positron emission tomography [PET] and CT. Prostate cancer cells absorb amino acids at a more rapid pace than healthy cells. Axumin concentrates on these specific cells, which are highlighted under a PET and CT scan.

The gallium-68 PSMA-11 test also uses an injectable radioactive agent in conjunction with a PET scan. Once injected, the agent binds to prostate-specific membrane antigen [PSMA], high levels of which are found in prostate cancer cells. This makes any PSMA-positive lesions in the prostate easier for a PET scan to see.

Additional research will guide how doctors might use these new diagnostic tests in the evaluation of men with possible prostate cancer.