Report Calls Mammography Screening 'Unjustified'
Jan. 6, 2000 (Atlanta) -- The scientific evidence that says women should get regular mammograms is flawed, concludes a hotly debated new report appearing in the current issue of The Lancet. Of the eight clinical studies of mammography screening -- in which a half-million women took part -- the report advises doctors to ignore six "biased" studies and to focus on two trials it says show no benefit for screening.
"We feel that the [beneficial] effect of mammography [screening] has not been proved," co-author Peter C. Gøtzsche, MD, tells WebMD. "The two well-done trials did not find any effect, even a trend. We do not say mammography is without effect, we say we could not see an effect. If there is an effect of mammography it is likely to be much smaller than we had previously thought."
The American Cancer Society takes strong exception to these conclusions. In an interview to provide objective comment, ACS chief medical officer Harmon Eyre, MD, dismisses the new data analysis in no uncertain terms. "The ACS continues to recommend that women get regular mammograms," Eyre says. "The most important person to get that done is the physician. We believe that by recommending regular mammograms, U.S. physicians have dramatically reduced breast-cancer mortality. We see no reason for them to stop doing so."
But Gøtzsche, director of the Nordic Cochrane Center in Copenhagen, Denmark, stands by the report. "My personal opinion is that if a woman turned to me for advice and asked me if she should join a mammography screening program, with examinations every second year, I would advise her not to do so," he says.
Eyre could not disagree more. "The American Cancer Society very strongly believes that mammography reduces the mortality rate from breast cancer and that the evidence is incredibly strong in the U.S.," he says. "The paper is arguing they haven't seen the same drop in breast-cancer death rates in other countries that is seen in the U.S., but no other country is doing [mammography screening] as frequently or as well as we do it in the U.S."
In an editorial also published in TheLancet, Harry J. de Koning, MD, PhD, from Erasmus University in the Netherlands, suggests that the report is too quick to reject the six trials seen as flawed. "In seven of the eight trials there was clearly a benefit for women age 50 and older," de Koning tells WebMD. "I'm still pretty much convinced that most of the trials were run quite adequately."
Gøtzsche and Ole Olsen reanalyzed the mammography studies when they learned that Sweden 's breast-cancer mortality rate did not decrease since mammography screening began in 1985. Six of the trials, they found, did not properly assign women to the study groups that either got or did not get mammograms.