A majority of all breast cancer diagnosis is made in older women. Yet women older than 75 are much less likely to undergo mammography screening than younger women. This is partly due to the lack of available research proving the efficacy of mammography in detection. A new study published in the online journal Radiology suggests that early detection with mammography reduces the risk of late-stage diagnosis in older women, allowing for early and successful intervention. These findings will encourage women over 75 to undergo regular mammography screening, say the researchers.

Previous data on age-specific mammography screening is quite ambiguous with the American Cancer Society recommending annual mammograms for women age 75 and older as long as they are in good health, while the U.S. Preventive Services Task Force (USPSTF) does not recommend mammography screening in this age group as there is insufficient evidence to evaluate its pros and cons.

"There are no studies on women age 75 and older, despite the fact that they are at the highest risk for breast cancer,” said Dr. Judith A. Malmgren, affiliate assistant professor at the University of Washington's School of Public Health and Community Medicine in Seattle. This, according to her, is why there are divergent views on mammography screening.

Dr. Malmgren and her research partner, Dr. Henry Kaplan, from the Swedish Cancer Institute in Seattle, studied over 14,000 breast cancer cases with 1,600 patients over age 75, to test the effectiveness of mammography screening. They found that mammography screenings could detect cancer in the early stages. This opposed to physician- and patient-detected cancers which were advanced stage disease.

Patients who were detected with cancer through mammography screenings often underwent lumpectomy and radiation and had fewer mastectomies and less chemotherapy than patient- or physician-detected cases. Also, mammography-screened patients showed a 97 percent five-year disease-specific invasive cancer survival rate, compared with 87 percent for patient- or physician detected invasive cancers.

"Mammography enables detection when breast cancer is at an early stage and is easier to treat with more tolerable options," Dr. Malmgren said in a press release. "In this study, older women with mammography-detected invasive cancer had a 10 percent reduction in breast cancer disease specific mortality after five years."

This early detection is very important in older women as advanced stage cancer treatments like chemotherapy are often not well-tolerated by them.

"Longer life expectancies for women also increase the importance of early detection," Dr. Malmgren said. "A 75- year-old woman today has a 13-year life expectancy. You only need five years of life expectancy to make mammography screening worthwhile."

The study also acknowledges the associated disadvantages such as costs of false-positive results of mammography. However, she said that false-positive findings are less common in older women.

"It's easy to detect a cancer earlier in older women because breast density is not an issue," Dr. Malmgren said. "And mammography is not expensive, so doing it every other year would not add a lot of cost to healthcare."

"Breast cancer survival in younger women has improved dramatically over last 20 years, but that improvement has not been seen in older women," Dr. Malmgren said hoping that this study would help to shed new light on breast cancers in older women and help them recognize the benefits of early screening.

Source: Malmgren J, Parikh J, Atwood M, Improved Prognosis of Women Aged 75 and Older with Mammography-detected Breast Cancer. Radiology. 2014.