PSA Firestorm: Mammogram Debate, Part 2?
It was a one-two punch that rattled the very foundations of the cancer world.
Two years ago, the U.S. Preventive Services Task Force questioned the benefit of routine mammograms for women under 50. And just this month, it advised that all healthy men avoid the prostate-specific antigen (PSA) test, which measures a protein in the blood that often spikes when prostate cancer is present.
In both cases, the highly influential, government-commissioned board warned that over-testing can bring more harm than good. And in both, the recommendations touched off a wave of protests from doctors, patients, and advocacy groups who insist that letting up on the tests could cost thousands of lives.
While it’s still unclear whether or not the PSA warning will change the habits of American men, a look back at the real-world implications of the mammography announcement in 2009 might offer some insights.
Dr. Barnett Kramer, editor-in-chief of the National Cancer Institute’s Physician Data Query (PDQ) Screening and Prevention Editorial Board, has been watching both controversies play out. He spoke to the NewsHour about what the comparison can tell us — and how far it should be taken.
These two controversies seem to parallel each other in a number of ways. How similar are they?
First of all, there is widespread screening already in place for both breast and prostate cancer. There is widespread public awareness for both of those screening tests. And there are specialty and advocacy groups that have had a very strong message in favor of the continuation of both of these routine tests.
Are there major differences distinguishing these two recommendations?
Well number one, the recommendations are differently nuanced. In the case of mammography, for women who are between the ages of 40 to 49, the task force offered a grade C recommendation, which means in their view the benefits and harms are closely enough matched that women should make an individualized decision. They don’t necessarily recommend against it. For women 50 and above, they offered a grade B, which means they have moderate confidence that the test is effective.
That stands in contrast to the prostate cancer recommendation, which is not nearly so nuanced or complicated. Their draft guideline gives prostate screening for all ages a grade D, which means they’re discouraging the service. There’s no nuance. They don’t differentiate by age. In the case of prostate cancer, the harms are frequent and can be substantial but the biggest harm is considered to be overdiagnosis. Prostate cancer tends to be a very slow-growing cancer. This test often picks up legions that never would have shortened a man’s life expectancy. The randomized trials don’t show a strong pattern of benefit, so the task force was more confident about the harms than about the benefits.
Did the mammography recommendation lead a large number of women to change their behavior?
At the national level, there’s been a leveling of the use of mammography for several years now, and maybe a slight decrease. That’s hard to attribute to a specific guideline issuance. It may even be due to saturation — there’s a relative ceiling on how many people are going to get this test.
Does the PSA pushback stand to make a significant difference in the number of men receiving the test?
If the task force sticks to its current proposed grade, men are likely to be faced with conflicting guidelines – just as there currently are in mammography. Again, the U.S. Preventive Services Task Force gives mammograms for women under 50 a grade C, saying that the benefits don’t necessarily outweigh the harms. But the American Cancer Society, the American College of Radiology, the Komen foundation and a number of others strongly disagree with that. For prostate cancer, if the U.S. Preventive Services Task Force finalizes these guidelines and makes it a grade D, it’s pretty clear some organizations, like the American Urological Association, will continue to strongly oppose them. And if that’s the case, men, just like women, will be faced with conflicting guidelines. How they will respond to that, I couldn’t tell you.
How much concern do you have that all of this back and forth is simply confusing the public?
Well there’s no way to relieve the public of the complexity because even before the updated guidelines, there was complexity. The U.S. Preventive Services Task Force previously recommended against screening men who are 75 and above for prostate cancer and said the evidence was inconclusive for men below that age. Other organizations still felt strongly that men of all ages should be routinely screened. I don’t think there’s an easy way to relieve the public of all of this uncertainty. Different organizations have traditionally looked at the same evidence and come to drastically different conclusions. You can’t dictate simplicity and it’s probably that it isn’t a simple issue. So we all face complex decisions day in and day out. That’s just part and parcel of the complexity of public health and medicine in general.
What advice do you have for someone who is considering whether they should be tested?
I know it sounds trite but they should read the evidence statement from the task force, which is publicly available, and try to understand why they came to the conclusion they did. And then they should go armed with that deeper understanding when they talk to their doctor. That’s the nature of personalizing medicine. Different doctors and patients will review the evidence and legitimately come to different conclusions. One person will say, ‘I want to get tested,’ another will say, ‘No, I don’t want to take the risk.’ An informed patient will be less confused. But even if not, they ought to understand what’s known about the benefits and about the harms and use that information in their final decision.
Photo by Mario Villafuerte/Getty Images.