By Elaine Schattner, MD|October 25th, 2011
I’m wondering is how to bring mainstream health journalists and women who are, lately, choosing not to have mammograms, to their senses about a persuasive but flawed argument put forth by a Dartmouth epidemiologist and others in a crew of seemingly like-minded, hopefully well-intentioned, some perhaps tenure-seeking and others grant-needing, circulatory bias-confirming academics who meet and discuss and write about the so-called dangers of mammography.
Maybe some doctors and journalists think they’re doing the right thing by informing a naïve body of women who, in the words of an LA Times writer today, think only correlative and simple thoughts.
If you or someone you know discovered she had breast cancer thanks to routine mammography screening, and if you or that friend with breast cancer got treatment and today is cancer-free, it’s natural to assume that the mammogram was a life-saver.
But odds are, it wasn’t….
First things first: the title makes an assumption about what I, or you, or any reader, thinks.
Second, the story offers two factoids: first – that over 75% of women diagnosed with BC by screening mammography wouldn’t have died from the cancer if they hadn’t had mammography; and second – that no more than 25% of those same women can rightly credit a mammogram for saving their lives. But this is just one stat, or falsehood, based on the true, assumption-free relationship between 75% and 25%.
Dr. H. Gilbert Welch, who recently likened mammography-taking to gambling, plays freely with impressive-sounding information sources. He and his coauthor used data from the NCI. Seemingly hard to argue with those kinds of numbers. But they used old data, again, and employ numerous assumptions (what the authors call generous, but I wouldn’t) to render calculations and “prove” their point published in the Archives of Internal Medicine.
The manipulative tone is set in the paper’s abstract:
“…We created a simple method to estimate the probability that a woman with screen-detected breast cancer has had her life saved…
Simple? Don’t you believe it.
There’s a Well post in the New York Times today covering the same Archives of Internal Medicine article. Not surprisingly, this draws positive feedback in the comments and Twitter-chatter. Some of the more understandable discussion comes from women with metastatic disease whose tumors were missed by screening mammography. Notably, neither paper quotes an oncologist.
Here in the U.S. where we do spend too much on health care, we all know women whose breast tumors were missed by screening mammograms. This happens, and it’s awful, but it doesn’t and certainly shouldn’t happen so often as some doctors seem to think. Extrapolating from personal observations to draw conclusions about a procedure’s value is flawed reasoning, either way.
But until there’s a prevention for BC, which I’m sorry to report is unlikely to happen before 2020, especially because it’s really 15 or 20 or maybe even more diseases that would, presumably, need distinct methods of prevention, and until there are better, less damaging and less costly remedies, mammography may be the best way for middle-aged women to avoid the debilitating and lethal effects of late-stage disease. And for society to avoid the costs of that condition and its treatments, which are huge.
post shortened 12/18/12