Like many of my friends, I’ve been struck by the sudden backlash against the new federal guidelines recommending that women begin getting regular mammograms at age 50 rather than age 40. Surely most of the people carping (I thought) lacked the knowledge base required to know at what point the benefit of detecting and treating real cancers early would outweigh all the costs associated with testing, including false positives and potentially unnecessary treatments. But as I headed home for Thanksgiving, it occurred to me that my father, a breast cancer specialist, does have the requisite knowledge base, and so I might has well get his take.
The short version is that he didn’t think much of the new recommendations either. He thought the conclusions were driven by bird’s-eye meta-analysis that glossed a lot of important details. For instance, he suggested that some of the data driving that conclusion came from Canadian studies showing few benefits because they disproportionately drew on cases from institutions whose antiquated equipment had a much higher error rate than that currently in widespread use in the United States. From an econometrician’s perspective, he told me, the studies are methodologically exemplary, but few clinicians would regard them as relevant to contemporary practice. He also thought the analysis was too quick to play down the value of follow-up biopsies that uncovered atypical but not-currently-malignant tissue.
Needless to say, that doesn’t mean “I have this friend who caught a tumor at 35…” is a good argument for setting a particular population-wide default, or that less testing won’t sometimes be the right answer. But it does sound like there’s some reason to be skeptical about this one.
Addendum: Since, as commenters note, my hazy recollection of our ten minute chat in the car is not exactly a fully rigorous argument, Dad passes along this more detailed statement from the Society of Breast Imaging.
4 responses so far ↓
1 Steve M. // Nov 27, 2009 at 8:19 pm
There is certainly a reason to be skeptical about everything. But the immediate backlash, correct or not, was mostly out of ignorance. I heard people say things like, “there is no such thing as over treatment!” I just think people should at least understand it first.
2 jme // Nov 27, 2009 at 8:35 pm
Sweet! We can have a Dad war! 😉
My father is a physician who has been following this issue for years, since primary care docs tend to have much more routine patient contact, and so it’s the primary care docs who most often are at the pointy end of the decision making process for routine screening, be it mammograms, cervical cancer or psa’s.
Anyhoo, he has said to me that the “they were using outdated equipment” argument is acultually bogus. He claims that if you control for how advanced the device used is, one still sees essentially no benefit under the circumstances proscribed by the new recs. (Under forty, average risk, etc)
Two other points. I find it telling that you dad is skeptical of the recs because “some” of the data included contradicts the conclusions. Did he elaborate on what fraction of the data this was?
Second, this entire line of argument succumbs to a dangerous fallacy about medical imaging for screening purposes. “Better” devices are usually better because the picture quality is higher. this means you see more stuff. BUT this in no way improves the clinicians ability to distinguish between thing in the image that will actually cause disease and things in the image that will not. and since the default procedure is to treat anything “suspicious”, this inevitably leads to more unecessary treatment. too many docs and patients assume that better pictures=better treatment. and it just ain’t necessarily so.
finally, speaking for myself, as a statistician, I’d want a he’ll of lot more sophistication in criticisms from a clinician than “meta analyses are too birds eye” and “some of the studies used older devices” from someone charged with guiding me though medical decisions.
anyway, I thought I’d share the opinions of another informed clincian, since that seems to be the standard for authority here.
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