Both Kopans and Dr. Otis W. Brawley, the American Cancer Society's chief medical officer, criticized the research team's short follow-up period -- just 2.2 years of observation, on average. They both said that the time frame was insufficient to assess the effect of screening.
In an accompanying editorial, Dr. H. Gilbert Welch, a professor of medicine and community and family medicine at the Dartmouth Institute for Health Policy and Clinical Practice in Lebanon, N.H., said the Norwegian study helps to confirm that the decision to undergo screening mammography is "a close call."
Welch, author of a book, Should I Be Tested for Cancer? Maybe Not and Here's Why, suggested that with better treatment and increased awareness of the importance of seeking care for breast abnormalities, screening mammography may be less important now than in the past.
"That physicians are still debating the relative merits of screening mammography despite the wealth of data suggests that the test is surely a close call, a delicate balance between modest benefit and modest harm," Welch wrote.
But Kopans noted that mammography is still the only test that has been proven to reduce the death rate from breast cancer and that this study should not divert attention away from that fact.
"It's clearly muddying the waters," he said.
Learn more about screening mammograms by visiting the U.S. National Cancer Institute.
SOURCES: Mette Kalager, M.D., epidemiologist, Cancer Registry of Norway, Oslo, and visiting scientist, Harvard School of Public Health, Boston; Daniel B. Kopans, M.D., director of breast imaging, Massachusetts General Hospital, and professor of radiology, Harvard Medical School, Boston; prepared statement from Otis W. Brawley, M.D., chief medical officer, American Cancer Society, Atlanta; Amer
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