Thursday, November 19, 2009

New Mammogram Guidelines

Last night, NPR interviewed Dr. Bruce Calonge, chair of the U.S. Preventive Services Task Force, which recently issued new recommendations for mammography this week. The previous guideline was that women should have them every 1-2 years starting at age 40. The new guideline is that women should have them biannually starting at age 50. This has caused huge controversy, of course.

The interview was singularly unhelpful, however, in helping to explain whether the new guideline is sensible or not. Dr. Calonge pointed out early on that the new guideline by no means restrict mammograms to women over 50; it merely recommends that women not automatically start getting them at age 40. Other considerations, such as lifestyle, family history, and other risk factors, may certainly lead a doctor and patient to opt for a mammogram earlier.

Fair enough, asked NPR's Tom Ashbrook, but what about women under 50 who have been diagnosed with breast cancer and lived because of the early detection provided by a mammogram? Dr. Calonge responded in three parts: first, that some of those women have risk factors that would have led them to have a mammogram anyway; second, that some of those women would have lived anyway because their treatments were unnecessary (apparently some breast cancers are treated aggressively even when they are not malignant); and third, that there are actual harms associated with mammograms, and that these harms must be weighed against the benefit of early detection.

I was hoping to hear more about these harms, because they is absolutely central to the cost/benefit analysis. We know the benefit of mammograms: it's fairly small in women under 50 (for whom the breast cancer rate is quite low), but is a positive number. If expense is not considered (and it was not by the USPSTF), then the only other costs would be health-related. Unfortunately, Mr. Ashbrook continued to focus on the fact that some women under 50 have had their lives saved by mammograms. Asked and answered, I kept thinking! Dr. Calonge continued to give the same answers, of course. What else could he say?

Looking it up on other sources, I find that the harms include: overdiagnosis (many studies show that as many as 10 breast cancers diagnoses are unnecessarily treated per life saved); exposure to radiation (a relatively small factor; apparently such exposure leads to approximately 1 life lost per 50 lives saved); and "stress" (mammography, unfortunately, yields a high rate of false positives - at least 10% - and a patient receiving such a result will naturally be upset by it). But is that it? These harms rate (in my mind) as: very common, but not at all severe (stress); somewhat common, and severe but not life-threatening (overdiagnosis); rare, but life-threatening (radiation).

When this combination of harms is placed on the scale against the life-saving benefits, which is weightier? It's pretty tempting to say "the benefits", without knowing more. (How can we say that ten overdiagnoses per life lost is a net negative? A life is pretty valuable.) And that's why Mr. Ashbrook's interview was so dissatisfying; had he probed the question of harms, Dr. Calonge might well have pointed out others that I missed in five minutes of Googling. Or perhaps the harms would have been as relatively minor as the ones I located. NPR did not do its job last night.

All of this has implications for the health care debate, of course. The GOP is making the point that this is the sort of rationing that you get under government-run health care. True, although of course it would get even worse if they were actually running the show, since then expense would inevitably be a factor. Still, it would be a mistake for the GOP to push this point too hard: having a government body change its recommendation is not the same thing as the government rationing care, and may be the right move for all we know: patients and doctors should make their decision individually, and the USPSTF has said no different.

Whether the USPSTF guideline has been improved or not, though, it smells like the government trying to prevent women from unnecessary, expensive treatments (that, by the way, might save your life), which is exactly the sort of thing that will come up more frequently the more government controls health care. The controversy over this one treatment shows that Americans do not want this. Let's hope their Senators are listening.

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