Study downplays benefit of routine mammograms
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LOS ANGELES -- Recent advances in breast cancer awareness and treatment have made routine mammography less crucial in detecting cancer and mitigated its value in reducing deaths, researchers reported Wednesday.
Although the World Health Organization and U.S. authorities have found previously that mammography reduces deaths from breast cancer by about 25 percent, the new study in the New England Journal of Medicine determined the death rate dropped by only 10 percent following the introduction of routine mammography in Norway.
The reduction was "far less than we expected," said Mette Kalager, a surgeon at Oslo University Hospital and the study's lead author. In fact, during the period covered by the study, the death rate among women over 70 -- who did not undergo mammography but received the same care as younger women -- dropped by 8 percent. That suggests that the benefit of mammography may have been as little as 2 percent, Dr. Kalager said.
In an editorial, H. Gilbert Welch of the Dartmouth Institute for Health Policy and Clinical Practice in Lebanon, N.H., called the reported benefit "disappointingly small." But he noted, "It is quite plausible that screening mammography was more effective in the past than it is now."
As more tumors are discovered earlier, because of increased awareness and more effective treatments are employed, Dr. Gilbert said, mammography becomes less valuable. Based on the new results, he said, 2,500 women would have to be screened for 10 years for one to avoid death from breast cancer. Meanwhile, at least 1,000 of those women would receive at least one false-positive result and five to 15 would be diagnosed and treated for a condition that was never going to bother them.
Otis W. Brawley, chief medical officer of the American Cancer Society, agreed that heightened awareness contributes to earlier detection of breast cancer, improving overall outcomes. Nonetheless, he said, "the total body of the science supports the fact that regular mammography is an important part of a woman's preventive health care."
First Published September 23, 2010 12:00 am
