What is the PSA test and why is it important?

Over the past 12 years, government guidelines on PSA prostate cancer screening have bounced around like a rubber ball. Should men get an annual PSA test or not? Let’s start with the basics.

What is the PSA test?

PSA stands for Prostate Specific Antigen. Antigens are small proteins found on the surface of prostate cells. They act as a kind of identification tag because they are specific to prostate cells. These proteins are “shed” into the bloodstream. When blood is drawn, a laboratory can determine the concentration of PSA, expressed as a numerical amount per volume. For example, if a PSA result is 2.5 ng/ml, it means 2.5 nanograms per milliliter.

Since all adult men have a prostate, it is perfectly normal to have a small but detectable amount of PSA. The important thing to know is that having a PSA test every year is a way to monitor any changes in the prostate. For example, as men age, the prostate gland tends to enlarge, a non-cancerous condition called BPH (benign prostatic hyperplasia). Since there are more prostate cells, starting at around age 50 it is not unusual for an annual PSA test to start showing slight increases slowly over time. There is no cause for alarm or concern.

Other things can also cause a higher PSA result, because any activity in the gland causes more antigens to be released into the blood. This includes infection or inflammation, but can also occur due to physical stimulation such as sexual activity, pressure from sitting on a bicycle seat, or a doctor performing a digital rectal examination (DRE or finger exam). Men are advised to avoid having sex or going on a long bike ride a couple of days before a blood draw. It’s also why blood draws must be done before a DRE, which can cause a temporary rise in PSA that can be misinterpreted as prostate cancer.

Likewise, prostate cancer (PCa) itself causes an increase in PSA. PCa cells are abnormal prostate cells, so they also have antigens. Since they behave more aggressively than normal cells and multiply, they release more PSA into the bloodstream and at the same time cause neighboring normal cells to eliminate more.

Here’s why the U.S. Preventive Services Task Force (USPSTF), a volunteer medical advisory board, has had mixed feelings about PSA testing. Approximately 1 in 8 men will have PCa in their lifetime. However, early PCa, which is very treatable, has no symptoms. Before the PSA test was developed in the mid-1990s, most PCa patients were diagnosed with advanced PCa and died from it. The PSA test changed all that! A high or rising PSA made early detection possible by sending a warning signal. Doctors then sent these patients for a needle biopsy to remove tissue samples from the prostate. These samples would be analyzed under a microscope by a specialist called a pathologist, who could give a definitive diagnosis that PCa is present. Suddenly, early detection of prostate cancer using the inexpensive PSA test began saving lives. Sounds good, right? In fact, it’s so good that by 2000, all men (ages 50 and younger, depending on risk factors) were encouraged to get an annual PSA screening test.

The PSA dilemma

But there’s a problem: A suspicious PSA result is not specific for cancer. A high number doesn’t necessarily mean PCa is present, but doctors are a cautious bunch. No responsible doctor wants to risk cancer growing in the man’s prostate gland, so the number of biopsies skyrocketed! Soon, one million prostate biopsies were performed each year in the U.S. Studies show true-positive (biopsy-proven PCa) rates of up to about 50%, meaning that about half of men undergoing undergo a biopsy, which carries risks of infection and discomfort, I do not have PCa.

Experts increasingly believe that not all PCa are equally dangerous. However, back then, men diagnosed with PCa were offered two general options: destroy the entire gland (surgery or radiation) or postpone treatment while PCa growth was monitored with PSA testing. Patients who chose to receive whole-gland treatment faced risks of urinary, sexual, and intestinal side effects. When the USPSTF reviewed this situation, they concluded that PSA testing causes three harms:

• Damage To: Too many biopsies that probably weren’t necessary, leading to
• Damage B: Too many men receive overly aggressive treatment that may not have been necessary, leading to
• Damage C: Too many men were left with urinary incontinence, erectile dysfunction and intestinal problems, some of them for the rest of their lives.

The dilemma is: how to preserve the good of the PSA and at the same time get rid of the damage?

Resolving the dilemma

The USPSTF did not see how to resolve the dilemma. Therefore, their position in 2018 is that men at low risk for PCa should talk to their doctors about the costs and benefits of a PSA test in their own situation. Unfortunately, since PSA testing became optional, the number of men diagnosed with PCa at a later stage has been slowly increasing, due to the drop in the number of annual PSA tests.

Now there is a solution. It started with a new specialized imaging technology called multiparametric magnetic resonance imaging (mpMRI), which offers a two-step way to solve the dilemma.

Step one: Wait several weeks after an abnormal PSA test, then repeat the blood test (remember: no cycling, no sex, no DRE before blood draw). This rules out laboratory error as well as unusual stimulation of the prostate prior to the above test. Keep in mind that repeating the PSA does not rule out infection or inflammation, but there are other ways to diagnose such conditions.

Step two: If repeat testing is still high, have an mpMRI to determine if a biopsy is necessary. If suspicious signs appear on the scan, an MRI-guided targeted biopsy uses a minimal number of needles precisely directed to the area in question, providing the most accurate diagnosis possible with the lowest risk to the patient.

Statistics show that approximately 30% of biopsies are unnecessary and can be avoided.

In my opinion, as a prostate cancer doctor, it is important to maintain the annual PSA test as a standard for men’s health. It is a gateway to early detection, leading to early diagnosis, leading to appropriately compatible treatment options with lower risks of side effects. This preserves the life-saving benefits of PSA while protecting men from unnecessary harm. And, for the record, going this route also saves money on long-term healthcare by eliminating unnecessary biopsies, overly harsh treatments, and the cost of managing months and years of treatment side effects. In my opinion, this is a win-win plan for all men.

NOTE: This content is for informational purposes only and is not a substitute for medical advice or diagnosis. Talk to your doctor if you have health concerns or questions of a personal medical nature.