Breast Cancer Found by Mammography: Older Women May Benefit
UPDATED // Although mammography is often not recommended for women 75 years and older, it might be beneficial for this age group, according to a study published online August 5 in Radiology.
Mammography-detected breast cancer in women 75 years and older has a number of advantages over breast cancer detected by older patients themselves or by their physicians, the researchers report.
Specifically, the machine-detected cancers were diagnosed at an earlier stage, required less treatment, and had better rate of 5-year disease-specific survival.
“Women should be informed of the possible benefit of a decreased need for aggressive treatment and better disease-specific survival with early detection with mammography,” write the researchers, led by Judith A. Malmgren, PhD, affiliate assistant professor at the University of Washington School of Public Health and Community Medicine in Seattle.
They note that the study is not a randomized controlled trial or an evaluation of a screening program, “which restricts our ability to make recommendations.”
The value of mammography screening in older women has been a hotly debated topic in recent years.
In 2009, the US Preventive Services Task Force concluded that evidence was “insufficient to assess the balance of benefits and harms” of mammography for women 75 years and older.
However, the American Cancer Society recommends screening these older women as long as they have no serious chronic conditions or a shortened life expectancy.
Women 75 years and older are not represented in screening effectiveness studies, Dr. Malmgren and colleagues observe.
A lack of research is chiefly responsible for the divergent recommendations, Dr. Malmgren said in a press statement. “There are no studies on women age 75 and older, despite the fact that they are at the highest risk for breast cancer,” she explained.
To rectify the situation, the researcher team reviewed an institutional breast cancer registry database for the period from 1990 to 2011 and identified 1162 women who were at least 75 years of age when they were diagnosed with stage 0 to IV disease.
Over the 21 year-period, 64% (744 of 1162) of the breast cancers (including ductal carcinoma in situ) were diagnosed with mammography and 36% (418 of 1162) were found by either the patient or the patient’s physician.
The average follow-up period was 7.3 years.
Most mammography-detected disease was stage I (62%), whereas most patient/physician-detected disease was stage II or III (59%).
Five-year disease-specific survival for invasive breast cancer was significantly better for mammography-detected disease than for patient/physician-detected disease (97% vs 87%; P < .001). The superior rate of survival is "likely the effect of fewer late-stage cancers," the researchers explain.
In addition, the treatment of invasive breast cancer was more likely to involve lumpectomy and radiation when disease was mammography-detected than when it was patient/physician-detected, and patients with mammography-detected disease underwent fewer mastectomies and less chemotherapy (P < .001).
Dr. Malmgren and colleagues emphasize the importance of the “downstaging” of breast cancer in this older age group. Early-stage lesions are “potentially treatable without chemotherapy,” they write. Avoiding chemotherapy is desirable because of “higher rates of comorbidities” and the “general lack of resilience” in older women receiving such toxic treatment.
They note that because these older women can live a long time, breast cancer screening should be considered. At age 75, life expectancy is another 13 years; at age 80, it is another 9 years.
In younger women (50 to 74 years), randomized clinical trials have demonstrated that mammography screening detects breast cancer at an earlier stage and reduces breast-cancer-specific mortality, the researchers report.
They they conclude that the benefits of mammography screening documented in younger women “may apply to women aged 75 years and older.”
Radiology. Published online August 5, 2014