Monday, December 7, 2009

Breast Cancer Screening Controversy

I'm going to be teaching two sections of epidemiology this Spring, one for grad students, one for undergrads.
The grad student version I'm pretty confident about, but I want to change a few things, especially the cumulative paper that I ask the students to write throughout the semester.
The other thing I'm thinking about is pulling in the breast cancer screening controversy, which seems to have long legs, re-appearing in the news on a regular basis. I had been thinking about H1N1, but to be perfectly honest, it hasn't been able to attract my attention (not the way the 1918 war-fueled epidemic did anyway).
For the undergrads, I'm trying out a new textbook (new to me, anyway), which has more pictures. I haven't been able to find a good textbook for undergrad epi, and the worst are the ones that say that that is their target audience.

Anyway, back to breast cancer screening. I think it's a great issue to tussle with. It has a lot of emotionally laden content in addition to "the science". The science itself is complex and fascinating, and really engages all forms of epidemiologic study designs, from case-control studies to massive experimental trials, and concerns epidemiologists have about sources of error and misleading results.

Also, one of the pioneering epidemiologic researchers was Janet Lane-Claypon, who did a case-control study comparing 500 women with breast cancer to 500 women without breast cancer, and confirmed most of the risk factors that we now know have a large influence on the development of breast cancer, in 1926. I like having a historical focus in my class, and it bugs me that that means reading exclusively male writers in a class that's predominantly made up of women.
I'd also like to include more of the large corpus of early writing from Spanish language authors, but I'm not familiar enough with it, and the few pieces I have seen translated just wouldn't fit well into my curriculum. (Perhaps it's time to expand my curriculum, then!)

But back to screening. I myself didn't think much about breast cancer screening, until my mom got a positive mammogram. It pretty well freaked her, and me, out. Weeks of anxious anticipation were not erased after minor surgery removed what turned out to be perfectly benign calcified lumps. But still, what if it had been cancer, wouldn't it have been good to know earlier rather than later?
The more I've thought and read about it, the more I've come around to a different point of view - it probably wouldn't have been better to know about it earlier. I know that sounds harsh to anyone with breast cancer, and easy for me, given that it wasn't breast cancer. But I don't say it glibly. The unnecessary anxiety, the unnecessary (if minor) surgery, these are not benign side effects. They may be mild inconveniences compared to mastectomy, chemo and/or radiation. But really how many unnecessary side effects are we generating with screening mammograms compared to how many treatable breast cancers that get detected (and wouldn't be equally treatable after they grew a bit and became diagnosed by other means)? How many breast cancers are detected and treated with highly toxic and invasive methods that, left alone, would never have caused a problem? Those are complicated questions that are technically challenging to answer.
Then, there's also an issue of where we, as a society, spend money. I don't think that costs should be a determinant of what health care people get. In a previous post, I lampooned the idea of doing a cost-benefit analysis of vaccination against HPV. The more effective a vaccine campaign is, the less cost-effective it would be, so it's just silly to do a cost-benefit analysis in the first place.
But at the same time, one wonders if all the attention paid to promoting mammograms as the one thing you can do to prevent breast cancer has crowded out other means of preventing breast cancer. Methods that may be less sexy, and less under an individual's control. Why does preventing breast cancer have to be something each woman does for herself? What about pesticides and environmental pollutants that probably have a very small influence on any one woman's risk of getting breast cancer, but by increasing all women's risks somewhat, have a large societal impact? What about the disparities in the levels of these pollutants that often mimic disparities in class and race in this country? What about addressing the structural poverty and disenfranchisement that keeps women from having symptomatic breast cancers dealt with early on when it's more treatable? These methods at least give men something to do!

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