Breast practices: The mammogram dilemma
There is growing evidence that screening mammograms aren’t all they’ve been cracked up to be. This month it was “More mammograms, more problems” — a study showing that screening every year (instead of every other) didn’t produce any benefit but did produce twice as many false alarms and twice as many biopsies. A few weeks earlier, another study (which I coauthored) suggested that roughly one-third of breast cancers diagnosed under current screening guidelines would never cause problems and didn’t actually need to be diagnosed.
There’s no question that diagnostic mammograms should be performed on women who have discovered a lump. But a growing number of primary-care physicians, surgeons, epidemiologists and women affected by the process have begun to question the value of telling all women they need to be checked regularly with screening mammograms. We are concerned about the human costs of screening: the fear created by the scare tactics used to promote it, the vulnerability caused by false positive or indeterminate test results (“it’s not cancer, but it’s not normal”) and the complications that result from overdiagnosis and overtreatment.
Recently a reporter asked me a deceptively simple question: What are people like you trying to do?
To answer this, it’s important to be clear about two things we are not trying to do: 1) stop women from getting screened and 2) prompt insurance companies to stop covering screening. Women who want to be screened should be. And because health insurance already covers many preference-sensitive services — services like hip replacements and back surgery — there is no reason it should not cover this one.
What we are trying to do is two things.
First, we want to give women the opportunity to make a choice. Screening mammography should be presented as an option, not as a public health imperative. To make that choice, women need to be given balanced information about its benefits and harms.
That is not current practice. Instead, women are subjected to persuasive messages that overstate the benefits while ignoring the harms entirely. There are the constant reminders, phrases such as “Screening saves lives. Get screened.” And there is also guilt and coercion aimed at those who opt out (“I can’t be your doctor if you refuse to get one”).
One big reason this occurs is that the proportion of women who get screened has been a long-standing performance measure in healthcare report cards. Health systems that score high on report cards are judged to have higher quality — and, increasingly, they are also paid more. Not surprisingly, they push their doctors to push mammography. The typical language is “we need to improve screening compliance.”
But the system’s interest in getting good grades shouldn’t trump a woman’s interest in having a choice. Fortunately, the fix is easy: Drop the screening mammography performance measure.
Our second goal is to have the mammography community acknowledge the harms. The motivation for this is simple: Acknowledging a problem is the first step in addressing it.
To be sure, some of the new generation of breast radiologists have openly acknowledged the problems of mammography; for a particularly good example of this, I recommend Dr. Handel Reynolds’ book “The Big Squeeze.” But many of the old guard are more likely to attack any suggestion of harm, characterizing researchers who raise the possibility of harm as malicious or dangerous and questioning the editorial policies of the journals that publish their work. In short, they seem more interested in denying problems than in solving them.
For decades, researchers have documented the problem of false positive mammograms. These are the mammograms that are judged to be possibly indicative of cancer but are subsequently proved not to be. In the interim, many healthy women have the scare of their life.
There will necessarily always be some false positive mammograms. But their frequency in the U.S. is extreme: Somewhere between 25% and 45% of women will have one in a 10-year course of mammography.
More recently, researchers have focused on the harm of overdiagnosis: the detection of abnormalities that meet the pathologic definition of cancer but are not destined to cause problems. The problem here is that anything called “cancer” gets treated with surgery, radiation and/or chemotherapy.
There will also always be some overdiagnosis — it’s a side effect of trying to catch cancer early. But it appears that somewhere between a quarter and one-half of all cancers detected during routine screenings fall in this category, and that is totally unacceptable.
False positives and overdiagnosis have the same root cause. They are the product of the conventional paradigm of cancer screening: Look harder and harder to find smaller and smaller abnormalities.
Call it the “find more” approach. Digital mammograms find more cancer than plain films, so they must be an improvement. Because breast MRIs find more cancer than digital mammograms, they must be better yet. It’s why newly touted 3D mammograms will undoubtedly be said to be better than anything else.
It’s a cycle of increasing intervention, a cycle that aggravates both the false positive and overdiagnosis problem. And it’s not clear it adds anything (but cost).
There is a fundamental asymmetry to screening: Only a very few can possibly benefit (those women who would die if their breast cancer wasn’t detected and treated), but any participant can be harmed. It requires a more elegant approach, one that finds the cancers that matter while minimizing the collateral damage.
There is no question in my mind we could preserve whatever benefits exist in mammography screening while reducing the harms. But that will never happen until the mammography community acknowledges that the harms exist.
H. Gilbert Welch is a professor of medicine at the Dartmouth Institute for Health Policy and Clinical Practice and an author of “Overdiagnosed: Making People Sick in the Pursuit of Health.” He is currently a visiting professor at Deep Springs College in Big Pine, Calif.
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