The New Health Dialogue

Here we go again. It’s time for the next skirmish in the mammography wars, sparked this week by the American College of Obstetrics and Gynecology’s new recommendation that women in their 40s get annual mammograms. The usual suspects have come out in droves, cheering the recommendations as a “victory for women’s health.”

I’m not going to get into the weeds of why this new recommendation is an example of faith-based (as opposed to evidence-based) medicine, but here’s a thought experiment: If yearly mammograms are a good idea, wouldn’t getting one every six months be even better? The idea behind yearly screening is to detect cancer early. Catch it before it causes symptoms and it’s curable. Let it sit around, growing undetected, and you’re more likely to die an early death. 

If that’s so, why not screen more frequently, say, every six months? I mean, if every woman in America over the age of 40 got a mammogram every year for the rest of her life, many would still die from breast cancer. The obvious solution here is to screen more often, and to start earlier than age 40.  How about at puberty? Better yet, why not screen women four times a year, or six? Surely bimonthly mammograms are not too high a price to pay for saving women’s lives.Actually, it is too high a price to pay, and not because of the dollars it would cost. None of the pro-mammography experts is recommending more frequent screening than once a year because they know that screening is not all benefit – even though that’s the way they often portray it. The reality is, 2,000 forty-year-old women have to get a mammogram every year for a decade in order to prevent one woman from dying of breast cancer.  This number is known as the Number Needed to Treat, or NNT. (There’s a great website, http://www.thennt.com, that shows in very simple terms, the NNT for many different tests, drugs, and procedures.)

Of course, if you’re that one who avoids dying of breast cancer, mammograms sound like a great idea. But here’s the downside: ten other women will be “overdiagnosed,” a fancy way of saying they’ll be told they have a bad cancer when they don’t. Six will have a lumpectomy, and four will have a mastectomy for a cancer that would not have caused them harm if it had been detected later in their lives or not at all. An unknown number of women die each year from getting treated for a breast cancer that did not need to be treated, and there’s no way to know ahead of time whether you will be one of the ones who is helped or harmed.

I’m not advocating for women to avoid mammograms. I’m advocating for truth-telling. Women need to know about mammography’s downside, so we can make the choice that’s right for us. If you are scared of dying of breast cancer, the possibility you’ll be treated and possibly harmed unnecessarily may seem like a risk worth taking. On the other hand, if you are scared of being harmed by medical intervention, it may be reasonable to say you don’t want to be screened.