The U.S. Preventive Services Task Force asked for public comment this week on its proposed new recommendation that most men don’t need routine screening for prostate cancer. Our comment: We agree. Here’s why.
The Task Force, an independent group of experts supported by the U.S. Department of Health and Human Services, made an exhaustive review of the scientific literature on the benefits and risks of the prostate-specific antigen (PSA) blood test. It concluded that the test was more likely to lead to substantial harm than to save lives.
The risk of PSA screening doesn’t come from the test itself, but from the treatments—mainly surgery or radiation—used when the cancer is detected. Specifically, the Task Force concluded that up to five men in 1,000 will die within one month of prostate cancer surgery and between 10 and 70 men will have serious complications but survive. In addition, at least 200 to 300 of every 1,000 men treated by surgery or radiation will experience urinary incontinence or impotence. Men who have radiation also face an increased risk of fecal incontinence and rectal bleeding.
Those risks might well be worthwhile if it was clear that screening for prostate cancer with the PSA test saved lives. But the Task Force concluded that was not the case. The two largest clinical trials to date—one European, the other in the U.S—found no statistically meaningful reduction in prostate cancer deaths in men who underwent the PSA test compared with men who did not. And a third study, which combined the results of all published trials, reached similar conclusions.
How could early detection of the cancer not save lives? The answer lies in the odd biology of the prostate gland. Autopsy studies suggest that many men—roughly 30 percent of those in their 30s, 40 percent of those in their 40s, 50 percent of those in their 50s, and so on—have some cancerous cells in their prostate. But in the vast majority of cases, those cancers never spread and aren’t deadly. Yet the PSA blood test, and follow-up biopsies, can’t reliably identify which cancers are aggressive and which aren’t. As a result, most men with prostate cancer detected by the PSA test get treated even though their cancer would never cause them harm.
Of course, all of this is very bad news, since prostate cancer remains the second leading cause of cancer death in men, trailing only lung cancer. But the solution, we think, isn’t to use a test that leads to more harm than good, but to focus on identifying a new one, or new guidelines, that work better. For example, until researchers come up with a new test, it’s possible that PSA testing might still make sense in men who are at high risk of prostate cancer because of a family history of death from the malignancy. The Task Force does not make any recommendation for such men, and additional research is needed to answer that question.
And of course, the recommendation against the test doesn’t mean that everyone should opt against it. Each man should make the decision for himself, based on his own assessment of his concerns about cancer and the possible consequences of treatment. But men should know the limitations of the test, and the potential complications of treatment, before being screened.
Unfortunately, that’s not the way PSA testing is currently done in this country. In fact, many men don’t even know that they had the test until after the fact, since the simple blood test often gets included as part of the routine blood work of a regular check up.
Finally, acknowledging the shortfalls of the PSA test is in no way meant to diminish the difficulties men face when they have the test and learn they have cancer. Once you find out you have cancer, it’s all but impossible to not do something about it. It’s unfair to men that they have been forced to make that decision without adequate information, and without a better test.
Click here to read the draft recommendations, and to leave your comments for the Task Force. And tell us what you think, too, by posting a comment, below.
Read more about the PSA controversy and the uncertain evidence.