Over the past 12 years, government guidance on the PSA screening test for prostate cancer has changed like a rubber ball. Should men have a PSA test every year? Let’s start with the basics.
What is a PSA test?
PSA stands for prostate-specific antigen. Antigens are tiny proteins on the surface of prostate cells. They act as a kind of ID tag because they are unique to prostate cells. These proteins “shed” into the blood. When blood is drawn, the laboratory can determine the PSA concentration and report it as a number per volume. For example, if the PSA result is 2.5 ng/mL, that represents 2.5 nanograms per milliliter.
Since all adult men have a prostate, the presence of a small but detectable amount of PSA is completely normal. It’s important to know that having an annual PSA test is one way to monitor changes in your prostate. For example, as men age, their prostate enlarges, a noncancerous condition called BPH (benign prostatic hyperplasia). Because the prostate has more cells, it’s not uncommon for annual PSA tests to start showing a slow, slight increase over time, starting around age 50. There is no reason to panic or worry.
Other factors can also cause an elevated PSA result, as 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, the pressure of sitting on a bicycle seat, or a digital rectal examination (DRE or finger exam) performed by a doctor. Men are advised to avoid having sex or riding bikes for long periods of time in the days before their blood draw. This is why blood should be drawn before a DRE, which can cause a temporary rise in PSA that could be misinterpreted as prostate cancer.
Likewise, prostate cancer (PCa) itself can cause an increase in PSA. PCa cells are abnormal prostate cells, so they also have antigens. Because they act more aggressively and multiply than normal cells, they release more PSA in the blood and also cause neighboring normal cells to shed more.
That’s why the U.S. Preventive Services Task Force (USPSTF), a voluntary medical advisory committee, has mixed feelings about the PSA test. About one in eight men will develop prostate cancer in his lifetime. However, early-stage prostate cancer is easily treatable and has no symptoms. Before the PSA test was developed in the mid-1990s, most PCa patients were diagnosed with late-stage PCa and died from the disease. The PSA test changes all that! A high or rising PSA allows for early detection by raising red flags. Doctors then have these patients undergo a needle biopsy, which takes a tissue sample from the prostate. These samples will be analyzed under a microscope by an expert pathologist, who can give a definite diagnosis of the presence of prostate cancer. Suddenly, early detection of prostate cancer through an inexpensive PSA test began to save lives. Sounds good, right? In fact, by the year 2000, all men (beginning at age 50 or younger, depending on risk factors) were urged to have annual PSA screening tests.
PSA’s Dilemma
But there’s a problem: Suspicious PSA results aren’t specific to cancer. High numbers don’t necessarily mean prostate cancer is present, but doctors are a cautious group. No responsible doctor wants to risk cancer growing in a man’s prostate – so the number of biopsies skyrockets! Soon, one million prostate biopsies were performed annually in the United States. No prostate cancer.
Now, experts are increasingly convinced that not all prostate cancers are equally dangerous. At the time, however, men diagnosed with PCa had two general options: destroy the entire gland (surgery or radiation) or delay treatment while monitoring PCa growth using a PSA test. Patients who choose to undergo whole-gland therapy are at risk for treatment side effects such as urinary, sexual, and intestinal side effects. When the USPSTF reviewed this situation, they concluded that PSA testing resulted in three harms:
- Hazard A: Too many biopsies that may not be needed, resulting in
- Hazard B: Too many men receive overly aggressive treatments that may not be needed, resulting in
- Hazard C: Too many men suffer from urinary incontinence, erectile dysfunction and bowel problems, some of which remain with them for the rest of their lives.
The dilemma is, how to preserve the benefits of PSA and eliminate its harms?
Solve the dilemma
The USPSTF doesn’t know how to resolve this dilemma. Therefore, their 2018 position is that men at low risk for prostate cancer should discuss the costs and benefits of PSA testing for their situation with their doctor. Unfortunately, since PSA became optional, the number of men diagnosed in advanced stages of PCa has been slowly rising due to a decline in the number of annual PSA tests.
Now there is a solution. The first is a new specialized imaging technology called multiparametric MRI (mpMRI), which offers a two-step solution to this dilemma.
first step: Wait a few weeks after an abnormal PSA test and then repeat the blood test (remember: do not ride a bicycle, have sex, or have a DRE before having your blood drawn). This rules out laboratory error and unusual prostate irritation before the last test. Note that a repeat PSA does not rule out infection or inflammation, but there are other ways to diagnose such conditions.
Step two: If it’s still high on repeat testing, get an mpMRI scan to determine if a biopsy is needed. If something suspicious arises on a scan, MRI-guided targeted biopsy uses the smallest number of needles to precisely penetrate the problem area, providing the most accurate diagnosis while minimizing risk to the patient.
Statistics show that approximately 30% of biopsies turn out to be unnecessary and avoidable.
In my opinion, as a doctor who specializes in prostate cancer, annual PSA screening is very important as a standard for men’s health. It is the gateway to early detection, leading to early diagnosis, which leads to appropriately matched treatment options with less risk of side effects. This preserves the life-saving benefits of PSA while protecting men from unnecessary harm. And, according to the record, taking this route also saves medical costs in the long run because it eliminates unnecessary biopsies, overly harsh treatments, and the cost of managing side effects for months and years of treatment. In my opinion, this is a win-win plan for everyone.
Note: This content is for informational purposes only and does not replace diagnosis or medical advice. If you have a health concern or personal medical question, please consult your physician.
