A Mammogram Every Two Years Is Best For Older Women

Receiving a mammogram every two years is just as advantageous for older women as getting a mammogram every year.

However, screening for breast cancer every two years results in significantly fewer false positives, researchers of a new study found.

The research, conducted by a team at the University of California, San Francisco, was published in the Journal of the National Cancer Institute and involved over 140,000 females who were between 66 and 89 years old.

Lead investigator Dejana Braithwaite, PhD, a UCSF assistant professor of epidemiology and biostatistics, explained:

"Screening every other year, as opposed to every year, does not increase the probability of late-stage breast cancer in older women. Moreover, the presence of other illnesses such as diabetes or heart disease made no difference in the ratio of benefit to harm."

The experts gathered and analyzed data from 1996 to 2006 on 2,993 older females with breast cancer and 137,949 females without breast cancer.

The data, taken from five Breast Cancer Surveillance Consortium (BCSC) mammography registries in Vermont, Washington, New Hampshire, North Carolina, and California, is "the largest available screening mammography data set in the United States," Braithwaite said.

There were no differences seen in late-stage breast cancer rates between the subjects who received a mammogram annually and those screened biennially.

On the other hand, the scientists discovered that 48% of women between 66 and 74 years old who received annual screening had false positive results, while only 29% of females in the same age group who received screening every other year had false positives.

Senior author Karla Kerlikowske, MD, a UCSF professor of medicine and a physician at the UCSF-affiliated San Francisco VA Medical Center, said:

"Women aged 66 to 74 years who choose to undergo screening mammography should be screened every two years. They get no added benefit from annual screening, and face almost twice the false positives and biopsy recommendations, which may cause anxiety and inconvenience."

Braithwaite added that the research "fills an important information gap, since accountable care organizations do not address screening intervals or screening cessation in women of advanced age or with a significant burden of illness."

The findings suggest that life expectancy and co-existing illnesses should be taken into consideration when informing recommendations in the future about cancer screening in older adults, Braithwaite concluded.

The U.S. Preventive Services Task Force's recommended that females ages 50 to 74 should receive screening once every two years.