Annual Mammography Starting at Age 40 Prevents Most Breast Cancer Deaths

Annual mammography screening starting at age 40 prevents the most breast cancer deaths, according to a comparison of the three most common screening recommendations.

Currently, there are several different recommendations for screening mammography from major national healthcare organizations, including annual screening at ages 40 to 84 years; screening annually at ages 45 to 54 years, then biennially at ages 55 to 79 years; and biennial screening at ages 50 to 74 years.

Researchers led by Elizabeth Kagan Arleo, MD, of Weill Cornell Medicine and New York-Presbyterian Hospital, used six computer models from the Cancer Intervention and Surveillance Modeling Network (CISNET) to estimate the possible effects of the three schemes. They found that the mean mortality reduction rate was greatest with the recommendation of annual screening at ages 40 to 84 years (39.6%), compared with the hybrid recommendation of screening annually at ages 45 to 54 years, then biennially at ages 55 to 79 years (30.8%), and the recommendation of biennial screening at ages 50 to 74 years (23.2%).

The researchers published their results in Cancer.

“Our findings are important and novel because this is the first time the three most widely discussed recommendations for screening mammography have been compared head to head,” said Arleo. “Our research would be put to good use if, because of our findings, women chose to start annual screening mammography starting at age 40. Over the long term, this would be significant because fewer women would die from breast cancer.”

For a single-year cohort of US women aged 40 years, assuming 100% compliance, more breast cancer deaths would be averted over their lifetime with annual screening starting at age 40 (29,369) compared with the hybrid recommendation (22,829) or biennial screening at ages 50 to 74 (17,153 based on 2009 CISNET estimates or 15,599 based on 2016 CISNET estimates).

To achieve the greatest mortality benefit, this single-year cohort of women would have the greatest total number of screening mammograms, benign recalls, and benign biopsies performed over the course of screening by following annual screening starting at age 40 years (90.2 million, 6.8 million, and 481,269, respectively) than by following the hybrid recommendation (49.0 million, 4.1 million, and 286,288, respectively) or biennial screening at ages 50 to 74 years (27.3 million, 2.3 million, and 162,885, respectively).

“Our results show the differences in the three current recommendations for screening mammography in terms of benefits and risks. Women and their physicians can use these findings to guide choices of when a woman begins screening mammography and how often she gets screened,” said coauthor R. Edward Hendrick, PhD, of the University of Colorado Denver.

The researchers acknowledged the limitations of mammography and the need to improve breast screening. They noted that the estimates of the number of women in the single-year cohort who would still die from breast cancer, even with 100% implementation, ranged from 44,671 with the first screening strategy, to 51,211 with the second strategy, to 56,887 with the third strategy.

They concluded that “if the goal is to avert the most breast cancer deaths and gain the most life-years, CISNET modeling shows that the optimal age of initiation for screening mammography is 40 years, the optimal screening frequency is annual, and the optimal stopping age is when a woman’s life expectancy is less than 5 to 7 years.”