For older women, skipping a mammogram every other year is probably a good idea, according to a new study from UC San Francisco. Biennial mammograms were just as beneficial as annual ones, and resulted in fewer false positive results for women between the ages of 66 and 74.
Data was collected on more than 140,000 women between the ages of 66 and 89 over the course of seven years. Rates of late-stage breast cancer were no different between women who were screened annually and those screened every other year.
Instead, the key difference between the two groups was that 48 percent of women 66 to 74 who were screened every year received false positive results. Conversely, only 29 percent of women in the same age group who were screened biennially received false positives.
The study authors hope this research, which used the largest available mammography screening data in the U.S., will influence cancer screening recommendations. Currently, frequency recommendations differ. The U.S. Preventive Service Task Force suggests that women should be screened biennially from age 50 to 74, while the American Cancer Society says screening should begin at age 40 and be done annually.
“The reason is that there is currently a gap in information about how often and whether to screen all women,” said study author Dejana Braithwaite, a UCSF assistant professor of epidemiology and biostatistics. “We were really interested in outcomes in this age group to provide evidence that could inform future guide lines for screening in the elderly.”
