Older Women With Strong Bones May Benefit From Mammograms
Dec. 7, 1999 (Washington) -- Tests that determine the health of bones in
older women could be used to pinpoint which women should have regular
mammograms once they reach age 65, and many who have a lower density do not
need screenings because they are at lower risk of breast cancer.
That's according to a study in the Dec. 8 issue of the Journal of the
American Medical Association by researchers at the University of
California, San Francisco (UCSF and the Veterans Affairs Hospital there. They
say four studies have shown that people with low bone mineral density, which
can produce osteoporosis and bone fractures, also have a lower risk of breast
cancer. This may be the case because, while the lack of the female hormone
estrogen can lead to brittle bones, high estrogen levels may have a role in
causing breast cancer.
The lead author of the study, Karla Kerlikowske, MD, tells WebMD that this
newest report is the first to suggest a revision of mammography guidelines for
screening schedules based on knowledge of bone density measurements.
Kerlikowske is an assistant professor of biostatistics and epidemiology at
UCSF. "I think the focus ought to be on women aged 50-69, where the benefit
is only moderate but at least there is a benefit. The benefit [of mammography]
is small for all people after age 70, and it is really small after
that," she says.
Today's guidelines call for all women aged 40 and above to have annual
mammograms. What many physicians say is puzzling is that there is no clear
guidance on what age to stop performing them.
This study compared the life expectancy of women who continue mammography
screening after age 69 with those who do not, based on bone mineral density
measurements taken when they were 65. It also addressed the costs to society of
mammograms and treatment of breast cancer, as well as women's preferences.
"We found that continued screening mammography to age 79 is moderately
cost-effective only if those with higher bone mineral density are
screened," the authors write.
But in an interview with WebMD, Gary Whitman, MD, an assistant professor of
radiology at the University of Texas M.D. Anderson Cancer Center in Houston,
says the study is "interesting" and should provoke further study, but
not a change in recommended mammography screening schedules.
"It presents some interesting ideas, but I don't think it calls for
marked changes in policies or practices," says Whitman, who reviewed the
study for WebMD. "I think it needs further study. We need to clarify what
is the role of estrogen in breast cancer. And, as they point out in the study,
we still don't know the efficacy of mammography in older women. A healthy,
vibrant 79-year-old should be screened, and if they are not [vibrant] ... that
is a decision that has to be made by the patient and the doctor."