By James Markland
Judith A. Malmgren, MD, Affiliate Assistant Professor, University of Washington’s School of Public Health and Community Medicine, and study co-author
When it comes to breast health, women at 75 may be wise to continue to act as if they are 40. A recent study funded by the Kaplan Cancer Research Fund and conducted at the Swedish Cancer Institute found that regular mammography exams could benefit women over 75 in unexpected ways. The study was published online in the journal Radiology.
Judith A. Malmgren, MD, affiliate assistant professor at the University of Washington’s School of Public Health and Community Medicine in Seattle, and her research partner, Henry Kaplan, MD, from the Swedish Cancer Institute in Seattle, recently examined the impact of mammography detection on older women. They studied data from an institutional registry that included more than 14,000 breast cancer cases with 1,600 patients over age 75. The researchers found the findings lend support to the practice of regular mammography screening in women ages 75 and older in spite of some prior belief to the contrary.
The value of mammography screening in older women has been the subject of considerable debate in recent years. The American Cancer Society recommends annual mammograms for women age 75 and older as long as they are in good health. In contrast, the US Preventive Services Task Force (USPSTF) does not recommend mammography screening in this age group, citing insufficient evidence to evaluate potential benefits and possible harmful effects.
In general, a potential harm of mammography is a false-positive reading, which may involve a biopsy for a finding that is not cancerous. The likelihood of a false-positive finding goes down with older age, as older women do not usually have dense breasts. Also, women who undergo mammography screening are at higher risk of a diagnosis of stage 0 breast cancer (ductal carcinoma in situ or DCIS). Although stage 0 breast cancer is cancer, some people do not feel it poses a threat to a woman’s health or mortality. According to Malmgren, this is a debatable point.
Malmgren says a lack of research is chiefly responsible for the controversy. “There have been no studies on women age 75 and older, despite the fact that they are at the highest risk for breast cancer,” she said. “Women age 75 and older are not included in clinical trials as they have competing forces of mortality at work. These include older age and comorbid conditions that increase their risk of death from any cause that compromises the length of potential follow-up.”
The recent research found that the majority of mammography-detected cases were early stage, while physician- and patient-detected cancers were more likely to be advanced stage disease. Mammography-detected invasive breast cancer patients were more often treated with lumpectomy and radiation with fewer mastectomies and less chemotherapy than patient- or physician-detected cases. Mammography detection was associated with a 97%, 5-year disease-specific invasive cancer survival rate, compared with 87% for patient- or physician-detected invasive cancers.
The early detection provided by mammography is particularly important in older women, Malmgren noted, because they cannot easily tolerate the chemotherapy that is commonly used to treat more advanced breast cancers. “Longer life expectancies for women also increase the importance of early detection,” Malmgren said. “A 75-year-old woman today has a 13-year life expectancy. You only need 5 years of life expectancy to make mammography screening worthwhile.”
For women age 75 and older who are healthy and have a reasonable life expectancy, continuing mammography screening in accordance with the American Cancer Society Guidelines appears to be supported by Malmgren’s findings. She notes that the results could use confirmation by investigating risk of breast cancer death associated with nonparticipation in screening in women 75 and older. The Women’s Health Initiative has data that could be used for such a study but only preliminary data have been reported so far. The challenge is the absence of information regarding participation in mammography screening programs linked to incidence of breast cancer and mortality from breast cancer at follow-up in national databases.
Apart from early diagnosis, there are few options to obviate the course of advanced breast cancer in the elderly population. Advances in survival related to adjuvant chemotherapy treatment improvements have been observed in younger women but do not appear to have an effect on older women.
The same advantages of mammography screening—diagnosis of breast cancer at an early more treatable stage—seen in younger women appear to extend to women age 75 and older. Women age 75 and older with a reasonable life expectancy should continue to participate in mammography screening programs in accordance with the ACS guidelines.
Breast cancer risk does not diminish with old age. Malmgren advises older women to make good choices, “Continue to participate in mammography screening as long as you are reasonably healthy to avail yourself of the advantage of an early treatable diagnosis. And mammography is not expensive, so doing it every other year would not add a lot of cost to healthcare.”
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