Annual breast cancer screening beginning at age 40 reduces mastectomy risk

Having a yearly mammogram greatly reduces the risk of mastectomy following breast cancer in women between the ages of 40 and 50, according to a study presented today at the annual meeting of the Radiological Society of North America (RSNA).

"The results of this study support the importance of regular screening in the 40 to 50 age group," said lead author Nicholas M. Perry, M.B.B.S., F.R.C.S., F.R.C.R., director of The London Breast Institute at The Princess Grace Hospital in London. "Women in this age group who had undergone mammography the previous year had a mastectomy rate of less than half that of the others."

An estimated 207,090 new cases of invasive breast cancer will be diagnosed in American women in 2010. Currently, the American Cancer Society recommends annual mammography screening for women beginning at age 40 in the U.S., but last year, the U.S. Preventive Services Task Force recommended changing the guidelines to begin screening biennially (every other year) at age 50. There are no routine screening guidelines for women under 50 in the U.K.

The researchers studied the benefits of screening women between the ages of 40 and 50, the frequency of mammography and the type of treatment after breast cancer diagnosis.

Dr. Perry and colleagues reviewed the clinical data available on women from 40 to 50 that had been diagnosed with breast cancer and treated at The London Breast Institute. Between 2003 and 2009, 971 women had been diagnosed with breast cancer. At the time of diagnosis, 393 (40 percent) of the women were under 50, with 156 of these women completing treatment at the center. Of the treated women, 114 (73 percent) had no prior mammograms. Forty-two women had been previously screened with mammography, of whom 29 had at least one mammogram within the previous two years. Of those, 16 women had a mammogram one year prior.

"We reviewed the records of the women needing mastectomy to determine whether or not they had undergone mammography the previous year," Dr. Perry said. "We were surprised at the degree of benefit obtained from yearly screening in this age group."

Data showed that mastectomy was the required treatment for 3 (19 percent) of the 16 women who had been screened the prior year, compared to 64 (46 percent) of the 140 women who had not been screened in the past year.

"Regular screening is already proven to lower the chance of women dying from breast cancer," Dr. Perry said. "The results of our study support the importance of regular screening in the under-50 age group and confirm that annual mammography improves the chances of breast conservation should breast cancer develop."

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Dr. Perry's coauthors are Sue Milner, B.Sc., D.C.R., Kefah Mokbel, M.B.B.S., M.S., F.R.C.S., Stephen W. Duffy, B.Sc., M.Sc., and Katja Pinker, M.D.

Note: Copies of RSNA 2010 news releases and electronic images will be available online at RSNA.org/press10 beginning Monday, Nov. 29.