For decades, men have dutifully shown up at their doctor’s office sometime around their 50th birthday for a baseline PSA (prostate-specific antigen test) to screen for prostate cancer.
As PSA levels rise, the theory went, so do your odds of having prostate cancer.
But in the last few years, the U.S. Preventive Services Task Force – the the same group of medical experts who made headlines by proposing that women under age 50 forego mammograms – has recommended that men no longer receive the PSA test even though statistics suggest they save lives.
Dr. Scott Van Appledorn, a urologist at EvergreenHealth in Kirkland, has more information about why you, or the man in your life, may benefit from PSA screening.
For starters, how does the PSA test work?
Dr. Scott Van Appledorn: A PSA test is a simple blood test that measures the amount of prostate-specific antigen (PSA) in the blood. PSA is a protein produced by both cancerous (malignant) and noncancerous (benign) prostate tissue.
Prostate cancer cells usually make more PSA than do benign cells, causing PSA levels in your blood to rise.
Elevated PSA results may reveal prostate cancer that’s likely to spread to other parts of your body (metastasize), or they may reveal a quick-growing cancer that’s likely to cause other problems.
Since PSA tests became common in the mid-1980s, the prostate cancer death rate has dropped. Also, aggressive prostate cancers, those that grow quickly or are likely to spread, are most treatable when caught early.
What are the arguments against PSA tests then?
Dr. Van Appledorn: While high PSA levels can be a sign of prostate cancer, a number of conditions other than prostate cancer can cause PSA levels to rise.
These other conditions could cause what’s known as a “false-positive” — meaning a result that falsely indicates you might have prostate cancer when you don’t.
Conditions that could lead to an elevated PSA level in men who don’t have prostate cancer include benign prostate enlargement (benign prostatic hyperplasia); a prostate infection (prostatitis); other less common conditions.
False-positives are common. Only about 1 in 4 men who have a biopsy due to an abnormal PSA test result actually have prostate cancer. These unnecessary biopsies are needlessly invasive, expensive and carry an acute risk of prostate infection for a very small number of men.
Additionally, most prostate cancer is slow growing and may never need treatment, meaning you would die from another cause before the prostate cancer harms you. Unnecessarily treating these cancers is another concern when evaluating men with prostate cancer.
Bottom line, how do you help your male patients navigate whether to get a PSA test or not?
Dr. Van Appledorn: Despite the Task Force recommendations, I still advise the men that I see to undergo a baseline PSA at age 50. This is because most people with prostate cancer have little to no symptoms, and the PSA test with a digital rectal exam and biopsy is currently the only available method to confirm prostate cancer.
This differs for men at high-risk, African-Americans and those with a first degree relative diagnosed with prostate cancer, who we recommend starting screening at age 40.
It’s also important to understand that a single elevated PSA test result doesn’t necessarily mean you will need a biopsy or cancer treatment.
To help distinguish a false positive from an upward trend, we’ll often set a screening schedule to repeat your PSA every six months. In fact, a study out just last week showed that repeating an abnormal PSA test can reduce unnecessary biopsies by 55 percent.
We’ll also consider your age, prostate size and other factors to help evaluate your PSA before determining a biopsy is needed.
Looking ahead, what advances might we see for prostate cancer screening?
Dr. Van Appledorn: While the PSA is good tool, it’s not a perfect screening test. I expect we’ll see significant advances in how we screen for prostate cancer in the next five to 10 years.
For example, work is underway to develop a non-invasive “liquid biopsy,” a blood test to determine the aggressiveness of the cancer. With such a test, we can get more information about the molecular profile of the cancer while avoiding surgical biopsies.
We’re also seeing exciting research focused on using cells in urine to identify which men with high PSAs are most likely to actually have prostate cancer, using proteins in biopsy tissue to determine the likelihood that prostate cancer will develop, and learning more about how to better predict which seemingly harmless prostate cancers will become lethal.
All this is significant progress in helping doctors overcome the present challenges: how best to identify – and advise – those who have slow-growing prostate cancer that requires only watchful waiting, those who can be treated if cancer is found early, and those whose cancer is incurable.