A task force advising the U.S. government on Monday recommended against routine use of the prostate-cancer screening test called PSA, or prostate specific antigen, for lack of a discernible health benefit.
Like a draft proposal last October, the U.S. Preventive Services Task Force gave PSA screening a D, for “don’t recommend” in healthy men.
The reaction was fast and furious. Screening advocates warned that the recommendation will cost lives, but critics of PSA testing said thousands of men will be spared impotence and incontinence as a result of needless cancer treatment.
A D means there is “moderate or high certainty” that a procedure has no net benefit or that harms outweigh benefits. It is a downgrade from the panel’s last PSA recommendation, in 2008, which said the evidence was insufficient to assess the procedure’s risks and benefits, although PSA screening for men 75 and older was not recommended.
Now, however, “there is convincing evidence that the number of men who avoid dying of prostate cancer because of screening after 10 to 14 years is, at best, very small,” the task force said in the May 22 issue of the Annals of Internal Medicine. Doctors, therefore, should discourage it.
The recommendation does not preclude men from asking for PSA screening, or doctors from offering it. But it could affect whether insurers, including the government’s Medicare program, cover the test’s $60 to $80 cost.
Prostate-Specific Antigen (PSA) Test
- Prostate-specific antigen (PSA) is a protein produced by cells of the prostate gland. The PSA test measures the level of PSA in the blood.
- The U.S. Food and Drug Administration (FDA) has approved the use of the PSA test along with a digital rectal exam to help detect prostate cancer in men age 50 and older. The FDA has also approved the PSA test to monitor patients with a history of prostate cancer to see if the cancer has recurred (come back).
- Doctors’ recommendations for PSA screening vary.
- The higher a man’s PSA level, the more likely it is that cancer is present, but there are other possible reasons for an elevated PSA level.
- Doctors take several factors into account for men who have a rising PSA level after treatment for prostate cancer.
- The PSA test for screening has limitations and is still controversial.
- Researchers are studying ways to validate and improve the PSA test and to find other ways of detecting prostate cancer early.
The only other screening method is the old-fashioned digital rectal exam, which cannot detect small, early cancers. Neither the exam nor PSA can distinguish slow-growing from aggressive cancers.
About one in six American men will be diagnosed with prostate cancer during his life; 2.8 percent, or a projected 28,000 this year, will die of it. Many cases pose no risk even without treatment. Research has shown that between one-quarter and one-third of 60-something men have prostate cancer, often without knowing it. Three-quarters of men older than 85 years have prostate cancer but few die of it.
PSA, a blood test, is a poor screening tool because PSA levels can rise for reasons unrelated to cancer, including age and prostate enlargement. Yet an elevated PSA level can trigger a biopsy to check for cancer.
Most biopsies show no cancer, which means the PSA was a false positive. But prostate biopsies that detect cancer do so based on research from the 1840s, explained Dr. Otis Brawley, chief medical officer of the American Cancer Society.
“As many as 70 percent of these lesions are cancer only by this antiquated definition and not in behavior,” he said. That is, they are indolent or inert and will not threaten a man’s health or life.
What is the prostate-specific antigen (PSA) test?
Prostate-specific antigen (PSA) is a protein produced by cells of the prostate gland. The PSA test measures the level of PSA in the blood. The doctor takes a blood sample, and the amount of PSA is measured in a laboratory. Because PSA is produced by the body and can be used to detect disease, it is sometimes called a biological marker or a tumor marker.
It is normal for men to have a low level of PSA in their blood; however, prostate cancer or benign (not cancerous) conditions can increase a man’s PSA level. As men age, both benign prostate conditions and prostate cancer become more common. The most frequent benign prostate conditions are prostatitis (inflammation of the prostate) and benign prostatic hyperplasia (BPH) (enlargement of the prostate). There is no evidence that prostatitis or BPH causes cancer, but it is possible for a man to have one or both of these conditions and to develop prostate cancer as well.
A man’s PSA level alone does not give doctors enough information to distinguish between benign prostate conditions and cancer. However, the doctor will take the result of the PSA test into account when deciding whether to check further for signs of prostate cancer.
Radiation oncologist Anthony D’Amico of Dana-Farber Cancer Institute in Boston acknowledges that PSA screening causes overdiagnosis, “but if you get rid of the PSA test, men will suffer and die of prostate cancer,” he said.
“I’m shocked that they would let people die in order to avoid incontinence and erectile dysfunction, which can be corrected.”