New Study Suggests Benefits of Regular Mammography Extend to the Elderly
Breast cancer afflicts 1 in 8 women in their lifetime, and 1 in 25 die from this disease. Although a number of randomized trials have demonstrated the clear benefits of mammography screening in women up to age 74 on reducing mortality, data are sparse in women over age 74, especially among minorities. In 2010, 41% of breast cancer deaths occurred in the more than 19 million women between the ages of 65 and 84 years.
Study Details
In a study published by Sanderson et al in the American Journal of Medicine, Charles H. Hennekens, MD, Sir Richard Doll Professor and Senior Academic Advisor to the Dean in the Charles E. Schmidt College of Medicine at Florida Atlantic University, indicated that black women and white women aged 75 to 84 years who had an annual mammogram had lower 10-year breast cancer mortality than corresponding women who had biennial or no/irregular mammograms. The American Cancer Society and the U.S. Preventive Services Task Force recommend regular mammography for women aged 65 to 74.
Although many guidelines rely on self-reports, Dr. Hennekens and colleagues used the Surveillance, Epidemiology, and End Results (SEER) program file linked to the Medicare administrative claims file, which allowed them to identify screening mammography use from 1995 to 2009 in 64,384 non-Hispanic women (4,886 black and 59,498 white). These linked files also permitted them to explore breast cancer mortality differences between elderly black or white women who self-selected for regular annual or biennial mammography screening. The researchers selected 69 as the lower age limit because Medicare coverage of the general population begins at age 65, and the exposure of interest was regular mammography screening in the 4 years immediately preceding breast cancer diagnosis.
Three mutually exclusive categories were defined: no or irregular mammography, biennial mammography, and annual mammography. They looked at data from non-Hispanic white or black women; Hispanics were not included because Hispanic white women have a substantially lower mortality than non-Hispanic whites, and the number of Hispanic blacks is small. The researchers also measured socioeconomic status looking at median household income, the percentage of individuals living below the poverty level, and whether or not they had a high school education.
Lower Breast Cancer Mortality Risk With Annual Screening
The group of 69- to 84-year-old women receiving regular annual screening mammography during the 4 years immediately preceding breast cancer diagnosis had consistently lower 5-year and 10-year risks of breast cancer mortality than women with no or irregular screening, regardless of race.
Ten-year risks were more than three times higher among white women and more than two times higher among black women aged 69 to 84 years with no or irregular screening compared with annual screening.
Significant findings from the study show that white women who had died tended to be older, to have a later-stage diagnosis, to have received chemotherapy, and to have a higher socioeconomic status. White women who died were less likely to have undergone surgery and receive radiation therapy. Similar characteristics were seen in black women and white women.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
