“At present the one certainty about PSA testing is that it causes harm.”
That quote comes from a British Medical Journal editorial published almost three years ago. And yet some doctors and many men still consider the prostate specific antigen test to be a reliable predictor of prostate cancer.
Chris Hiley, M.D., of the UK Prostate Cancer Charity recently told BBC News that further research is needed to “definitively assess the value of the PSA test.”
Let’s put that another way, and be very clear so that every man understands what’s at stake: A PSA test should not be used as a basis to proceed with invasive procedures that often do more harm than good.
Half & half
PSA is a protein that’s naturally produced by the prostate gland. Prostate tumors typically cause an over-production of PSA, so when a blood test reveals an elevated level of the protein, it’s a red flag that warns of possible cancer. And if elevated PSA were only caused by cancer, then we’d be talking about a truly reliable test. The problem: PSA levels also raise when the prostate becomes infected or when a benign enlargement occurs.
A new study from the Yale School of Medicine underlines the folly of assuming that the PSA test is anything close to a gold standard for prostate cancer detection.
As reported in the most recent issue of Archives of Internal Medicine, Yale researchers compared the medical records of about 1,000 subjects; half the men had been diagnosed with prostate cancer and died between 1991 and 1999, and half were men of the same age, chosen at random.
After researchers analyzed cases in which subjects had undergone PSA testing and/or digital rectal exam (DRE), they reported that “a benefit for screening was not found” in PSA testing and all-cause mortality.
Even more surprising, when PSA tests were combined with DREs, the results were actually worse.
The Yale researchers concluded that the results of their study “do not suggest that screening with PSA or DRE is effective in reducing mortality.”
So are these tried and “true” methods of checking for prostate cancer worthless? Not at all. But like any tools, their value depends on how they’re used.
Healthcare pioneer William Campbell Douglass, II, M.D., has referred to PSA tests and their follow up biopsies as “the mainstream’s slash-and-burn approach to prostate cancer.” But the slashing and burning isn’t caused by the test; it’s caused by doctors who react inappropriately to the test.
When PSA is elevated, many doctors recommend a biopsy of the prostate; a painful procedure that can result in bleeding and infection. But evidence shows that a great number of these biopsies are completely unnecessary.
In the e-Alert “Screen Pattern” (7/24/03), I told you about a Memorial Sloan-Kettering Cancer Center study in which researchers tested the reliability of a single PSA result. Over a 4-year period, five blood samples were collected from nearly 1,000 men over the age of 60. More than 20 percent of the subjects were found to have PSA levels that would have prompted many doctors to recommend a biopsy. But half of those men had follow-up tests with normal PSA levels.
The Sloan-Kettering conclusion: A single test that shows an elevated PSA level should be followed with additional screenings to monitor PSA fluctuation.
This research backs up another study I told you about in the e-Alert “Under the Knife, Under the Gun” (7/23/02). Doctors at the Fred Hutchinson Cancer Research Center estimated that PSA screening resulted in an over-diagnosis rate of more than 40 percent.
Men take note: Never trust a single PSA test, and never ever allow a doctor to perform a biopsy based on a single test.
“The Effectiveness of Screening for Prostate Cancer” Archives of Internal Medicine, Vol. 166, No. 1, 1/9/06, archinte.ama-assn.org
“Doubt Over Prostate Cancer Test” BBC News, 1/10/06, news.bbc.co.uk