CHICAGO - Many frail elderly women who get routine mammography suffer significant burdens from the screening procedure with little chance to benefit from it, says a study from researchers at San Francisco Veterans Affairs Medical Center.

Frail elderly women, who often have limited life expectancies, are less likely than younger women to have their lives extended by treatment of breast cancer detected by mammogram, the researchers said. Yet some of these women are screened, and many suffer the physical and psychological stresses of follow-up testing.

The researchers assessed the burdens of screening mammograms among 216 women who were enrolled in an at-home care program for women who would otherwise be eligible for enrollment in a nursing home.

"When the state audits programs such as the one we studied, one of the quality indicators they look for is the percentage of female patients who receive mammography," said the study's lead author, Louise Walter, MD, a geriatrics fellow at SFVAMC and the University of California, San Francisco. "We suspected that, for many of these women, the burdens of mammography might outweigh the potential benefits."

The findings were presented here at the annual meeting of the American Geriatrics Society.

Walter and her colleagues tracked the women for roughly two-and-a-half years, and found that while 38 women (18 percent) tested positive on their mammogram and were given further testing, only four of them actually were diagnosed with breast cancer.

In addition, two of the diagnosed women died of other causes within a year-and-a-half after treatment, suggesting the cancer detected by the mammogram would not have created symptoms during their lifetime. So, the discovery and treatment of cancer in these women caused unnecessary harm, Walter said. The other two women treated (0.9% of the screened population) were still alive at the end of the study and so may have benefited from the screening, Walter said.

The key point, Walter said, is that doctors should distinguish between women who are more likely to benefit from screening and those who are not. If a woman's remaining life span is estimated to be short, it doesn't make sense to screen them since potential burdens clearly outweigh potential benefits, she said. "In many of these cases, a frail older woman spends the last several months of her life dealing with the trauma of testing positive for breast cancer and being treated, when it turns out the disease wouldn't have affected her anyway because she already had a life-limiting illness," she said.

Walter argued against the standards used by state auditors from the California Department of Health Services to assess the quality of care in at-home care programs for frail elderly women, which use the number of mammograms performed as a measure of quality. These standards ought to allow physicians to use their best judgment when making screening decisions, Walter said. "There has to be some change in the language of these quality indicators. Perhaps they should simply be recommending a discussion by the doctor of breast cancer screening," she said.

The decision whether or not to screen should be based on the health and a comparison of the potential benefits and burdens for the individual patient, as well as the patient's own preference about screening. "The health status and life expectancy among older women is much more variable than for younger women so screening decisions need to be individualized," she said.

"We are not saying that older women shouldn't be screened. If a woman is healthy and is expected to live for many years, then screening may be the right decision," Walter said. But frequently, for frail women in their seventies or eighties, the decision is more complicated, she added. "We need more information about outcomes of screening tests in frail older adults," she said.

Co-authors on the study included Catherine Eng, MD, medical director at On Lok Senior Services; and Kenneth Covinsky, MD, MPH, staff physician at SFVAMC and UCSF assistant professor of medicine.

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The San Francisco Veterans Affairs Medical Center has been a primary affiliate of University of California, San Francisco since 1974. The UCSF School of Medicine and the SFVAMC collaborate to provide education and training programs for medical students and residents at SFVAMC. SFVAMC maintains full responsibility for patient care and facility management of the medical center. Physicians at SFVAMC are employed by the Department of Veterans Affairs and also hold UCSF faculty appointments.