By Richard C. Frank, MD
This past week, a government appointed scientific advisory board, the United States Preventive Services Task Force (USPSTF), reported its findings after reviewing the available scientific evidence regarding the effectiveness of the PSA test to prevent deaths due to prostate cancer. The board concluded:
“Prostate-specific antigen–based screening results in small or no reduction in prostate cancer–specific mortality and is associated with harms related to subsequent evaluation and treatments, some of which may be unnecessary.”
In short, the panel recommended that men no longer take a PSA test. Is this good advice?
The PSA test is a simple blood test that can lead to the early detection of cancer, when it is at a curable stage. The problem is that many men so diagnosed may not need treatment because the cancer is not destined to spread. Also of extreme importance is the physical cost of treatment: impotence and incontinence, among others.
On the other hand, many lives have been saved by the test, as the early detection of cancer in some individuals will be life-saving; the problem is that we cannot tell for which individuals this is true.
The recommendation of the USPSTF has resulted in confusion among healthy men (“Should I take the test”), those with a history of treated prostate cancer (“Should I have taken the test? Did I get treated for no benefit?”), and also physicians (should doctors order this cancer screening test anymore?). It is therefore critical that we ask: Is this conclusion valid? Should men forego the PSA test and just wait for the cancer to cause symptoms?
Did the panel make the right recommendation based on the evidence?
To me, this is the critical question. As with any medical recommendation based on evidence, the soundness of that recommendation is only as good as that evidence. Importantly, the board acknowledged that the evidence is not overwhelmingly conclusive against testing:
“PSA-based screening identifies more prostate cancers, but most trials found no effect on risk for death from prostate cancer. However, the 2 largest and highest-quality trials reported conflicting results.”
One of the large trials, in which PSA testing was not performed every year, did in fact demonstrate a reduction in prostate cancer deaths.
The panel is very concerned, and rightly so, about the high personal cost to individual men (and the high economic cost to society) as a result of overtreatment. But they did not consider the consequences of undertreatment:
Let us recall that before PSA testing, approximately 35% of men with prostate cancer had the disease diagnosed when it was in the most advanced, incurable stage (bone metastases causing pain). Today, that number is less than 10% (this is an observation, not data from a published study that would have been considered by the panel).
For all of the reasons, I think that the USPSTF recommendations are too harsh. The blanket recommendation that the PSA test no longer be used as a screening tool goes too far in favor of trying to avoid overdiagnosis and treatment.
I believe that men should continue to be screened for prostate cancer but within the following guidelines, mentioned in a recent article in the publication HemOnc Today:
- Perform the PSA test at greater than yearly intervals, perhaps every 2 years.
- No longer perform the test on men age 75 and older.
- Favor screening men in high-risk groups, such as those with a family history of prostate cancer at an early age or who are of African-American heritage.
- If a cancer is found that has low-risk features, favor observation (and monitoring for cancer progression) over immediate treatment.
As always, discuss the risks and benefits of any cancer screening test with your doctors.