Are Mammograms Bad For Your Health?

TAKEN AT FACE VALUE, THE LEAKS DESCRIBING A major medical study last week were profoundly disturbing. It's already known that about 1 in 9 American women will develop breast cancer during her life. Now, said the report, it turns out that women ages 40 to 49 who get routine mammograms to detect early breast cancer are actually more likely to die from the disease than those who avoid the tests. Most experts currently believe it's the other way around, and many doctors have long urged women in that age group to have a mammogram every year or two. If the evidence suddenly pointed the other way, standard medical advice would have to change immediately, public service announcements would have to be yanked and the estimated 75% of American women ages 40 and older who have had the procedure would have every reason to panic -- and to get angry at the bad advice they've been given.

But for now, the panic is premature. Despite the early alarms, it turns out that the study says no such thing. In fact, it can't, since the authors haven't finished analyzing the raw data yet. As everyone from pollsters to physicists know, raw numbers can be misleading until they have been subjected to statistical analysis. Says Dr. Anthony Miller, the University of Toronto researcher: "Anyone who says the statistics lead to such a conclusion at this point is wrong."

What the study does say, according to Miller, is that mammography has no demonstrable benefit for women in that age range, though it does for older women. While those who get mammograms are no more likely to die from breast cancer than their untested counterparts, they are evidently no safer either. That in itself is not unprecedented: earlier studies have pointed to the same conclusion. But it is controversial. No one is sure why it should be true, and for now, the medical establishment is not backing off its recommendation that women between 40 and 49 go ahead and get tested.