Mar 21, 2003
(HealthScoutNews) — When doctors detect an abnormality on an annual mammogram and are fairly certain it’s benign, they usually recommend a repeat screening in three to six months just to be sure the lesion hasn’t changed or grown.
Researchers, however, say that physicians are overusing the recommendation, that the frequency with which it is given varies greatly among centers, and that the yield of positive breast cancer diagnoses is very small.
They tracked the incidence of breast cancer among almost 60,000 women who were participants in the Women’s Health Initiative study and found that 2,927 of them had received recommendations for speedier follow-ups.
Of those, only 1 percent were diagnosed with breast cancer within two years after that first mammogram, says study author Dr. Patrick Romano, an associate professor of medicine at the University of California, Davis, School of Medicine.
And of that 1 percent, or 30 women, only 11 were diagnosed within a year after the screening mammogram; for the rest, it took longer.
That compares to breast cancer incidence rates of .6 percent for women whose baseline mammograms were found to be benign and .5 percent for women whose baseline tests were found to be negative over the same two-year period.
According to guidelines put forth by the radiology community, about 1 percent to 2 percent of all screening mammograms should result in a recommendation to repeat at three to six months, Romano says.
“But we found in the national sample from the Women’s Health Initiative that it was about 5 percent and that there is a lot of variation across centers. In some centers, it was as low as 1.2 percent and in some areas as high as 9.8 percent,” Romano says.
“We are not making definitive recommendations based on this paper; we are sort of contributing to discussion and debate,” he adds. “We are saying this recommendation is being applied more often than experts say it should, applied with a lot of variation across centers, and the percentage of women who benefit from this is lower than what people thought.”
The authors of the paper, which is published in the March 19 issue of the Journal of the National Cancer Institute, conclude that the results should stimulate re-examination of the criteria used to make follow-up recommendations and that one-year follow-ups might be more appropriate.
“There’s a lot of anxiety caused by false-positive mammograms,” Romano adds. And the follow-up testing is inconvenient, costly and time-consuming. Physicians may overuse the category because they are nervous about possible litigation, Romano says, or because they don’t have a prior mammogram for comparison.
“It’s clear from their study that the category is being used much more frequently than is intended by the American College of Radiology,” says Dr. Karla Kerlikowske, an associate professor in the departments of medicine and epidemiology and biostatistics at University of California, San Francisco, who co-authored an editorial on the study. “The second aspect is, you can’t tell how it was being used, because they didn’t have enough information [in the paper] about the prior mammogram.”
“What was unusual about the study is usually this category is only used on first mammograms when you don’t have the previous film,” she says. One explanation might be the physicians did not have access to prior mammograms.
Based on the study, Kerlikowske says there are two messages for women.
“It is very important they have their prior mammogram,” she says. “A second thing is, they can always get a second opinion.”
But Barbara A. Brenner, executive director of Breast Cancer Action, a grassroots advocacy organization based in San Francisco, notes that while the percent of women for whom the repeat mammogram resulted in a cancer diagnosis was small, it is not small “for the women for whom it ends in diagnosis.”