Study Supports Mammography in Women 75 Years and Older

In a study that has the potential to change public health recommendations for breast cancer screening, researchers have validated the value of mammography in older women.

According to researchers at the University of Washington, Seattle, the benefits of mammography extend to women older than 75 years.

Explaining the need for the study, lead author, Judith A. Malmgren, PhD, noted, "There are no studies on women aged 75 and older, despite the fact that they are at the highest risk for breast cancer. Breast cancer survival in younger women has improved dramatically over the last 20 years, but that improvement has not been seen in older women."^1,2

As a result of the lack of data, the United States Preventive Services Task Force has not issued a ruling on whether insurance coverage of mammography screening for women aged 75 years and older is warranted. The benefits of mammography, however, have been well validated in younger women between the ages of 50 and 74 years. The lack of a recommendation in older women carries negative ramifications because it affects insurance coverage and treatment decisions.³

To change this recommendation, Malmgren and colleagues prospectively tracked 1162 women with biopsy-confirmed breast cancer between 1990 and 2011. Investigators tracked the patient characteristics, including the stage of breast cancer at diagnosis, as well as mortality outcomes.¹

Over the 21-year study, investigators noted an increase in the percentage of new breast cancer diagnoses identified using mammography in patients older than 75 years. In this age group, the percentage of new breast cancers recognized through mammography increased just under half (49%) of patients between 1990 and 1994, to more than two-thirds (70%) of patients between 2010 and 2011.¹

Tumors identified through mammography were more likely to be small tumors in the early stages of progression (stage 0 or I). In addition, cancers were more likely to have the favorable treatment characteristic of expressing estrogen receptors, which allows physicians to treat patients with certain modalities that are not available in other types of breast cancer.¹

Moreover, as the detection method shifted to mammography over time, the stage of detection grew significantly (P = .007) earlier, with the proportion of patients with stage 0 cancers increasing from 3% of new diagnoses in 1990 through 1994 to 18% of new diagnoses between 2010 and 2011. Over the same period, the percentage of patients with stage III cancers at diagnosis fell from 18% to 10%.¹

Earlier detection through mammography was also associated with improved survival. The 5-year relapse-free survival rate of patients with mammography-detected breast cancer was 96%—significantly (P <.001) higher than the 87% 5-year relapse-free survival rate observed in patients who first detected breast cancer through other methods.¹

According to Malmgren, “Mammography enables detection when breast cancer is at an early stage and is easier to treat with more tolerable options. In this study, older women with mammography-detected invasive cancer had a 10% reduction in breast cancer disease-specific mortality after 5 years.”²

This study may lead to an update of recommendations in breast cancer screening in the United States, and may change insurance coverage policies for mammography screening in women aged 75 years and older.¹

References:

• Malmgren JA, Parikh J, Atwood MK, Kaplan HG. Improved prognosis of women aged 75 and older with mammography-detected breast cancer [published online August 6, 2014]. Radiology. 2014.
• Regular mammograms for over-75s beneficial. http://www.irishhealth.com/article.html?id=23923. Accessed August 6, 2015.
• United States Preventive Services Task Force. http://www.uspreventiveservicestaskforce.org/uspstf/uspsbrgen.htm. Accessed August 6, 2015.