Women over 75 who learned more about the risks and benefits of mammogram screenings were less likely to go through with the test in a new study.
Women should have a mammogram — an X-ray of the breast tissue scanning for early signs of cancer — every two years between ages 50 and 74, according to the U.S. Centers for Disease Control.
According to the U.S. Preventive Services Task Force, a government-backed expert panel, there isn't enough evidence to recommend for or against mammograms for older women.
A woman's choice to have a mammogram past the age of 75 should be based on her life expectancy, risk of disease and personal preference, study author Mara A. Schonberg, M.D., said.
"Approximately, 20 percent of U.S. women 75 and older have less than five year life expectancy and these women should not be screened since they are very unlikely to benefit and can really only be harmed," she said.
"About two thirds of women 75 and over have less than 10 year life expectancy and some experts would argue that these women are also unlikely to benefit. About one third of women have more than 10-year life expectancy and it probably makes sense to recommend screening to these women."
Dr. Schonberg studies patient decision making at Beth Israel Deaconess Medical Center in Brookline, Massachusetts.
For the study, 45 women over age 75 who had been regularly having mammograms, as recommended by their doctors, but had not had one in the previous 5 months were given the decision aid — a packet of information on the risks and benefits of screening for women in their age group — before deciding at a doctor's appointment whether or not to schedule another screening.
The women filled out an experience survey before reading the packet and again after their doctor's appointment.
The packet included information on breast cancer risk for women over 75 and the risks of screening including false positives and costly and stressful follow up testing.
For older women, many tumors that a mammogram would find would actually grow too slowly to harm the woman in her lifetime, Dr. Schonberg said. But nearly all women with breast cancer are treated for it, and the risks of treatment increase with age.
Based on the two surveys, women tended to be more informed about the benefits and risks after reading the packet than before.
Before reading the decision aid, 37 of the 45 women planned on having a mammogram, compared to 25 out of 45 who planned to do so after reading it.
According to medical records, 26 of the women had a mammogram in the two years following the study.
Dr. Schonberg thinks it would be feasible to give this type of decision aid to all women over 75 as they make screening decisions, but "it requires our health care system placing greater value and resources in decision support for patients."
Giving the decision aid to women over 75 before a visit with their primary care doctor seemed to work well in the study, but in the real world it would take resources to identify these women and send them the information, she said.
"In practice, it may be faster for a physician to simply recommend a mammogram than to discuss patients' preferences around screening," she said. Doctors should be compensated for spending time discussing this issue with patient, she said.
"In addition, most of the educational materials regarding mammography screening have been uniformly positive. It takes a change in culture to acknowledge that there are both benefits and risks to screening and that each woman should be allowed to make an informed decision for herself."
All women should be informed of the risks and benefits of screening, she said, but especially those over 75, since there are more risks and uncertain benefits for this group.
The study did not follow the women to determine which, if any, were later diagnosed with breast cancer.
"Most women over age 75 should not get mammograms," H. Gilbert Welch, M.D., a professor of medicine at the Dartmouth Institute for Health Policy & Clinical Practice in Hanover, New Hampshire, said. "But this is not unique to mammography, or women," he said.
Dr. Welch authored another study on the risks of mammography screening for older women in the same issue of JAMA Internal Medicine. In it, he estimates that for 1,000 women who get annual mammograms starting at age 50 for 10 years, "0.3 to 3.2 will avoid a breast cancer death, 490 to 670 will have at least 1 false alarm, and 3 to 14 will be overdiagnosed and treated needlessly."
"As people get older — closer to death — there is less reason to look for cancer early," he said. "Most people, men and women, over age 75 should not be screened for cancer."
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