Prostate Cancer Screening: What to Know

Screening for prostate cancer starts with a blood test for prostate-specific antigen (PSA). PSA is a protein that’s made by prostate cancer cells, but it’s also made by the normal prostate. “PSA levels can be elevated for lots of different reasons, which is why it is just the first step in screening — to see if men fall in a concerning area that needs further investigation,” says Dr. Barbieri.

Dr. Anderson says that if a patient is at or above three or four, then further testing is recommended. “The lowest threshold is a PSA over three, although we adjust that considering a patient’s age,” he says. “For instance, you may not consider a PSA of three in a 75-year-old man the same way you would in a 45-year-old man. It is important to keep in mind that even though PSA is the best test we have for screening, it is not a perfect test. There are many men who have an abnormal PSA who end up not having any cancer.”

A rectal exam may also be a part of the evaluation and can offer helpful information, although Dr. Barbieri acknowledges that patients may feel a little bit of discomfort. “The prostate is right in front of the rectum, and because prostate cancer often begins in the back of the gland, it can sometimes be felt during a rectal exam,” he says.

If more information is needed after the PSA blood test and rectal exam, doctors can order imaging, such as an MRI. MRIs offer a better look at suspicious areas of the prostate and potential areas to target should a biopsy be needed. Says Dr. Anderson: “Something to keep in mind is, if you have a normal looking MRI, is a prostate biopsy still required? Although men with a negative MRI have a low risk of having a significant cancer, this risk estimate can vary with image quality, radiologist experience, and patient factors. This is one component where additional urine or blood tests may have an advantage in ruling out the presence of significant cancers.

A JAMA study published recently evaluated a urine test that can detect cancer genes for high-risk prostate cancer in the urine. “Around a third of patients in the study’s cohort safely avoided a biopsy with low risk of missing a clinically significant cancer,” says Dr. Anderson. “There are several reasons why we’ve tried to reduce the number of prostate biopsies we perform. Generally, we hope to avoid doing a biopsy in men who do not have cancer or who have low-grade prostate cancer, which does not tend to metastasize or cause death. Men with a negative biomarker test like this one could safely avoid a biopsy without risking their longevity or health. There is also some risk involved with prostate biopsies, including a small risk of infection. And it is uncomfortable.”

Says Dr. Barbieri: “Additional blood tests, such as the 4K Score or Prostate Health Index (PHI), can also help clarify when results are in a gray area. These tests measure not just PSA, but other PSA variants that refine the risk of finding prostate cancer.”

The only way to definitively know if a man has prostate cancer is by doing a biopsy of the prostate. A biopsy typically entails a short, in-office procedure to remove small samples of prostate tissue. “I tell men that there are three things we can find on the biopsy,” says Dr. Barbieri. “One is nothing, when everything looks fine. The second is low-grade prostate cancer, which is slow growing. We typically do not recommend treating this type, but we do suggest monitoring it through an approach we call active surveillance, which is when we monitor the cancer over time. The third thing is high-grade, more aggressive prostate cancer, which is what we try to take care of and make sure that we do not miss.”