Mammography Significantly Cuts Risk of Advanced Cancer in Elderly
Feb. 28, 2000 (Atlanta) -- While fewer women 70 and older receive
mammograms, a new study shows that they -- like younger women -- can benefit
from having breast cancer detected in its early, potentially curable stages.
Breast cancer is the second leading cause of cancer death in women over age 65,
according to a study published in this month's American Journal of
In the study, a review of nearly 700,000 Medicare records showed "a
clear benefit [of mammography] in women in this age group," lead author
Rebecca Smith-Bindman, MD, assistant professor of radiology, epidemiology, and
biostatistics at the University of California, San Francisco, tells WebMD.
"It's pretty impressive."
While a number of studies have looked at mammography's success rate in
diagnosing cancer, there have not been sufficient studies focusing on women
over age 65. Only two studies have included women between ages 70 and 74, and
they were too small to provide meaningful results, she says.
"This is important, because we need to know at what age we should stop
giving women mammograms. I think it's obvious to everyone that if you screen a
90-year-old woman for breast cancer, you're probably not helping [her] very
much," says Smith-Bindman, who is currently on sabbatical as visiting
professor at the Wolfson Institute of Preventive Medicine in the Royal London
School of Medicine.
Smith-Bindman and colleagues reviewed two years' worth of Medicare records
of 690,993 California women between 66 and 79 years old. They found a 43%
reduction in advanced breast cancer among those who had mammograms. They also
found that small, early cancers were 3.5 times more likely to be diagnosed
among women who were screened.
"Mammography is supposed to find cancer early, when it's not
symptomatic, but we found a lot of small cancers. It means there might
be a whole reservoir of breast cancer that wasn't going to hurt women [if it
went untreated] because these women probably would have died from heart disease
or other forms of cardiovascular disease. The problem is, some of those cancers
would have hurt women. Once you find them, there's no way to tell which
are the harmful ones and which would be relatively silent," says
While all women who have cancer need to be treated, she says, "the
dilemma is that to some degree you are overdiagnosing cancer in elderly women
if you screen them. We're definitely helping women by finding these cancers,
but it's not clear exactly what the trade-off is."
A woman in her 70s, who is otherwise healthy, has a long life expectancy and
would clearly benefit from mammography, says Smith-Bindman. "On the other
hand, if she's a woman with a lot of chronic illnesses, she will probably not
benefit from screening. In that woman, you may be finding small cancers that
really will not shorten her life. She likely will die from cardiovascular
disease, heart disease [or] another chronic disease."