Mammograms Less Effective Than Believed
Only 10% Fewer Breast Cancer Deaths With Routine Mammograms
Routine Mammograms: A Close Call
So should U.S. women continue to get routine mammograms? It's a "close call," says H. Gilbert Welch, MD, MPH, of the Dartmouth Institute in Lebanon, N.H.
"This is a test that women who want it should be able to have," Welch tells WebMD. "But it should not be jammed down people's throats. ... The system we are working in leads doctors to coax, scare, and coerce women into having this test."
Why would a woman at normal risk of breast cancer want to get routine mammograms? The obvious answer is that these tests save lives.
How many lives? If the full 10% drop in breast cancer deaths among screened women in the Norwegian study is totally due to mammograms themselves -- Welch calls this an optimistic assumption -- one life is saved for every 2,500 women who get regular mammograms.
But what's the harm of routine mammograms?
"The biggest harm is you are treated for breast cancer unnecessarily, for a cancer that was never going to cause problems," Welch says. "Because we don't know which cancers these are, all cancers are treated. This means some women will undergo needless surgery, radiation, or chemotherapy. On balance, this is about five to 15 of those 2,500 women screened."
Moreover, a large number of screened women will have worrisome mammogram results.
"Among the 2,500 women screened, at least 1,000 will be told something looks wrong on their mammogram, and they will have to worry that they have cancer," Welch says. "The vast majority will turn out not to have cancer, but all of them will worry."
Welch notes that many women may find that the benefits of routine mammograms outweigh these risks.
"Every woman has to make her own decision about how to weigh these very dissimilar things," Welch says. "Some will benefit in a very large way. But to achieve that benefit, a lot of others will have to go through something with very negative effects. It is not wrong to want a routine mammogram, and it is not wrong not to want one."