If regular mammograms really saved lives, they ought to show lower death rates in a big systematic study. But they didn’t, in the latest and biggest research study, published this week, on this once sacrosanct pillar of preventive medicine.
The numbers say it all. Some 90,000 Canadian women were assigned by a coin flip into one of two groups: regular mammograms, or regular breast exams by a nurse. Then they were followed for 25 years.
Of the 45,000 who got mammograms, a little over 3,000 were diagnosed with breast cancer, and 500 died of it. But of the 45,000 who got no mammograms, the same outcomes were recorded: a little over 3,000 were diagnosed with breast cancer, and 505 died of it.
One in 474 women in the mammogram group were subjected to unnecessary surgery, radiation and/or chemotherapy.
This is a story we’ve covered a bunch of times. Much as many of us would like to believe that early detection saves lives, and that anyone who says otherwise must be in league with the Simon Legrees of the insurance industry to save money by denying coverage, still, it’s hard to argue with the numbers.
The new study was impressive not just because it was so big, but because the researchers were able to figure out that one big improvement in breast cancer treatment, the drug tamoxifen, has pushed the survival curve up enough to wipe out the logical advantage of earlier detection of tumors too small to feel.
The growing body of statistical evidence on mammograms does NOT mean the mammogram machines should all be junked, or that women should ignore obvious lumps in their breasts. It DOES mean that one-size-fits-all doesn’t work, and you need to consider your own circumstances and tailor an approach that works for you.