PSA tests: Can they save men from prostate cancer?
October 11, 2016
The prostate-specific antigen (PSA) test is used primarily to screen for prostate cancer. PSA is a protein produced by cells of the prostate, which is a walnut-sized gland that produces the fluid in semen. PSA levels often are elevated in men with prostate cancer.
Stiller’s essay reinvigorated a years-old debate between medical professionals about the PSA test and screening for prostate cancer. Some, including myself, believe the PSA is a valuable tool to help us detect prostate cancer, which is the second-most-common cancer in men after skin cancer. Others argue that more men are harmed than helped by the screening because of false positives and subsequent testing.
Let’s take a look at prostate cancer risk factors, what current screening guidelines and studies say about the PSA, and how I advise men to approach this test.
What are the risk factors for prostate cancer?
One in seven men will be diagnosed with prostate cancer during his lifetime, according to the American Cancer Society. The risk of developing prostate cancer increases as men age, with 60 percent of cases in men older than 65.
Other risk factors for the disease include:
- Race and ethnicity: Prostate cancer occurs more often in African-American men and in Caribbean men of African ancestry.
- Family history: Prostate cancer runs in some families, so having a first-degree relative (such as a father or brother) with the disease can increase a man’s risk.
- Genetic mutations: A small percentage of prostate cancer cases may be caused by inherited gene mutations. This can include mutations in genes such as BRCA1 or BRCA2, or in men with Lynch syndrome.
What do the prostate cancer screening guidelines say?
PSA screening guidelines vary across organizations. For example:
- U.S. Preventive Services Task Force: In 2012, the Task Force recommended that men without symptoms not get PSA tests at any age. However, officials say the Task Force is currently reviewing the latest studies and may update its guidelines.
- American Cancer Society: The organization’s 2016 guidelines recommend that men at average risk for prostate cancer discuss screening with their doctor beginning at age 50. Men at high-risk should consider screening at 45.
- American Urological Association:The organization’s 2013 guidelines recommend that a discussion about PSA testing occur before 55 for men at high risk, between 55 and 69 for men at average risk, and at 70 for men in good health.
He wrote in his essay: “If (my doctor) had waited (to get me a PSA test), as the American Cancer Society recommends, until I was 50, I would not have known I had a growing tumor until two years after I got treated. If he had followed the U.S. Preventive Services Task Force guidelines, I would have never gotten tested at all, and not have known I had cancer until it was way too late to treat successfully.”
So why is there such little consensus about when men should get a PSA test or whether they should get one at all? It comes down to the perceived risks and debated benefits of testing.
Why the debate over the PSA test?
Critics of the test say there are too many risks associated with it. They often point to:
- False positive results, in which the test detects cancer that is not present.
- False negative results, in which the test does not detect cancer that is present.
- Risks associated with unnecessary procedures from false positives, such as biopsy or surgery.
- Psychological stress that may accompany frequent or further testing to diagnose cancer.
- Perceived overtreatment (removing benign tumors) leading to permanent urinary and sexual problems.
The issue isn’t when or whether men should be screened, but whether men with abnormal screening results are properly diagnosed and treated. It’s unreasonable to blame the PSA test on inappropriate cancer treatment.
Critics also say research has not proven that routine PSA testing actually saves lives. However, our team has not changed our PSA screening recommendations, despite guidelines suggesting that men not receive the test.
What do studies show about the PSA test?
I don’t think there’s any doubt that PSA testing has saved lives. Prostate cancer mortality rates began to fall several years after the introduction of PSA screening, according to the American Urological Association. By 2008, mortality rates had fallen nearly 40 percent compared to the early 1990s.
This decrease in mortality is the largest of any cancer, including the drop in lung cancer mortality rates after the advent of smoking cessation programs.
However, the two largest studies on the effects of PSA testing came back with opposite findings:
- Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial (2012): This study of more than 76,000 men found that those who had annual PSA testing along with a digital rectal exam (DRE) had the same rate of death from prostate cancer compared with the control group of men who received standard care, including some opportunistic – rather than annual – PSA screening.
- European Randomized Study of Screening for Prostate Cancer Trial (2014): This trial of more than 162,000 men showed a 20 percent reduction in prostate cancer deaths in men who had routine PSA testing compared to those who didn’t.
This leaves the European study as the definitive study on the effect PSA testing has on saving lives.
My advice for men regarding the PSA test
Let’s look at an example outside of medicine to give the issue of PSA testing some perspective. Assume there is a known potential problem with all automobiles that can cause a deadly accident. Let’s say there is a test that can detect the problem. If the test is negative, an accident is very unlikely. If it’s positive, there is a one in three risk of having such an accident.
Would you get your car tested? Most people would. And these are roughly the same odds when you do a PSA test and perform the biopsy if the test is positive.
PSA testing is not perfect. But it’s the best screening we have right now to detect prostate cancer early. Prostate cancer symptoms usually don’t appear until the disease is advanced, so having a tool to detect it before symptoms appear is essential. Medicare provides coverage for PSA testing for men 50 and older, and many private insurers cover it as well.
Talk with your doctor about when you should be tested, what follow-up tests should be performed if your PSA level is high, and how to treat prostate cancer if it’s diagnosed. I recommend finding a skilled urologist to guide you through these questions and decisions.