What Your PSA Test Says About Your Prostate

THIS YEAR, IT’S estimated that nearly 300,000 new prostate cancer cases will be diagnosed. While there’s no single test to detect prostate cancer , doctors commonly use the prostate-specific antigen blood test as a screening tool .

The test measures the amount of PSA, a protein that your prostate makes, in your blood, explains Richard Levin , M.D., a urologist and vice chief of staff of the medical executive committee at HCA Florida Adventura Hospital.

“Elevated PSA blood test means there is some abnormality, the most concerning of which is prostate cancer ,” he says. But it doesn’t necessarily mean that you have cancer.

The American Urological Association recommends that you get a baseline PSA test between ages 45 and 50, but screening can start at age 40 for those at a higher risk for prostate cancer , such as Black men or people with a family history of the disease, says Karyn Eilber , M.D., a urology professor at Cedars-Sinai Medical Center.

Then, you should get re-screened every two to four years until you turn 69 if you’re not in a high-risk group, the AUA says. Along with the PSA test, your doctor may also do a DRE (digital rectal exam) to feel the prostate for lumps or other abnormalities.

When you get screened for prostate cancer, it's important to discuss with your doctor what you'll do with the results, she says. Here’s an overview of what PSA test results mean and the next steps if your levels are high.

What Your PSA Test Results Mean

The PSA is a good initial “check engine light” for the prostate, says Garrett Pohlman , M.D., a urologist and host of The Prostate Health Podcast. But it can just tell you that PSA levels are elevated, not what exactly is going on with the prostate.

Several things can cause a high PSA, including prostatitis, benign prostate enlargement, or prostate cancer, Dr. Pohlman says. Recent ejaculation can also increase PSA, Dr. Eilber says. PSA naturally increases as you get older, too.

A PSA of 4 nanograms per milliliter (ng/mL) is typically the cutoff that doctors use to recommend more testing, according to the American Cancer Society . If your levels are between 4 ng/mL and 10 ng/mL, you have about a 25 percent chance of having prostate cancer. Your chance of having the cancer rises to 50 percent when your levels are 10 ng/mL or higher.

What Happens When Your PSA Score Is High

If your test shows high PSA levels, doctors may recheck your blood or do a urine test to check for an infection that might be causing the elevation, Dr. Eilber says.

Dr. Pohlman says he also uses the new EpiSwitch PSE blood test , which became available in the U.S. last year, but isn't yet widely used. It measures epigenetic biomarkers for prostate cancer and is combined with the PSA test. Research shows combining the PSA and PSE can improve the accuracy of prostate cancer detection.

A biopsy or MRI may be recommended when you have an elevated PSA or if a PSE test shows a result of “high likelihood for prostate cancer,” Dr. Pohlman says.

Anyone with an abnormal DRE should be considered for a biopsy, regardless of their PSA test, Dr. Eilber adds.

What You Should Know About Prostate Cancer Grading

If cancer is detected, it's graded based on how abnormal the cancer cells look under a microscope, according to the American Cancer Society . Cancers that look more abnormal and are more likely to grow quickly have higher grades.

There are a couple of different ways to grade prostate cancer:

What to Know About the Gleason Score

A Gleason score is commonly assigned to cancer. Prostate cancer is usually graded between 6 and 10, Dr. Levin says. Scores below 6 are rarely used. (This is important; see more below. You might think that if your score is "all the way at 6," you have a big problem. But that's not so with this. A 6 is a very low score.)

Prostate cancers are often divided into three groups based on the Gleason score, according to the ACS. Here's what the scores mean:

• 6 or less: “well-differentiated” or “low grade”
• 7: “moderately differentiated” or “intermediate-grade”
• 8 to 10: “poorly differentiated” or “high-grade”

Grades are assigned to two areas that comprise most of the cancer. The two grades are added together to come up with the Gleason score.

For instance, if most of the tumor is a grade 3 and less of it is a grade 4, it would be written as 3+4=7 for a total Gleason score of 7.

“The lowest possible score you can get is a 3+3=6, suggesting a slow-growing cancer,” Dr. Pohlman says. “The highest possible score is 5+5=10, which would infer a more aggressive cancer, more likely to grow and spread quickly.”

What to Know About Grade Groups

While the Gleason score is still widely used, there’s a newer way to grade prostate cancer, known as the Grade Group system, which Dr. Pohlman says is more simplified. This allows prostate cancers to be divided into more than just the three groups included in the Gleason score.

Grade Groups range from 1, or likely to grow and spread slowly, to 5, or likely to grow and spread quickly, according to the ACS:

• Grade Group 1 = Gleason 6 (or less)
• Grade Group 2 = Gleason 3+4=7
• Grade Group 3 = Gleason 4+3=7
• Grade Group 4 = Gleason 8
• Grade Group 5 = Gleason 9-10

“Currently, many pathology reports note both the Gleason score and the Grade Group, but there are still pathologists that report only the Gleason score,” Dr. Pohlman says.

Treating Prostate Cancer

Many treatment options are available depending on your specific cancer case, Dr. Levin says. Treatments can include surgery, radiation or hormone therapy, chemotherapy, immunotherapy, and others.

Sometimes, no treatment is needed just yet when you get diagnosed, and “active observation” is recommended, he says.