New USPTF Guidelines – I finally know enough to write something.
The new USPTF guidelines for breast cancer screening have been a super hot topic for the last week. We started out with outrage, moved to outrage at the outrage, and are finally settling into a state of reasonable interpretation. The growing consensus (that I’ve seen) is that the USPTF guidelines are not so far off, but their wording could have been much better. It is true that mammograms before the age of 50 have a low positive predictive value, and thusly a high false positive rate. It is also true, based on the USPTF data, that for every 1000 women screened annually between 40 and 50 years of age, over 50% of them will need additional imaging at one point, 20% will get a breast biopsy, and only 1-2 breast cancer deaths will be prevented. Based on this, it is clearly worth discussing whether patients 40-50 should be getting mammograms.
But the world, at first, didn’t want to discuss it. We immediately attacked the USPTF, even accusing them of somehow being in league with new health care reform policies meant to reduce costs, at the known expense of women’s lives. Even Sanjay Gupta went attack dog against one of the USPTF members live on CNN. That was the most surprising thing to me.
But now people are starting to come around, and they are coming around pretty much to where I started.
My initial reaction to the guidelines wasn’t so negative. The USPTF aren’t a bunch of dummies. They are educated people who looked at the situation from a epidemiological and mathematical point of view. And from that point of view, their recommendations are sound. People who argue that they don’t care about individual women fail to realize that they are asking for something that cannot be. Epidemiology, almost by definition, ignores individuals. It is about large groups of people, and mathematically defining the interactions of various interventions on those groups. It isn’t about individual people at all, and to think that epidemiologists should professionally care about individuals is to misunderstand their very nature.
We need epidemiologists, for the very reason that everybody attacked them. They think about the large groups and ignore individuals, so that we doctors can think about individuals and ignore the large groups. We need them so that we can think about our patients as infinitely important, because they think about the population as infinitely important. We are Kirk. They are Spock.
The fact that their analysis says that women 40-50 shouldn’t get mammograms doesn’t mean that doctors should completely stop ordering them. It just means that on a population level, it doesn’t make sense. That doesn’t mean that it is wrong for everyone under 50. Their analysis just means that we need to think about it a little more. We need to talk to our patients and explain that mammography in a low risk 40 year old woman has some downsides. And then we let them decide.
I’ve been a little slow posting on this topic, because honestly I felt a little ignorant. I was amazed that so many people felt so versed in the situation that they were able to condemn the USPTF’s recommendations so thoroughly, and so quickly. I didn’t write anything because I just didn’t know yet. I’m finally writing now because I finally understand just enough of it to say something that is worthwhile to me. I still don’t get it all, but enough to write at least a few words.
Some other people have written some thoughtful posts as well, that are worth a read: