Breast cancer incidence in women in their 40s supports the recommendation for annual screening from age 40.
Women in their forties comprise 18.8% of all screen-detected breast cancers, suggesting that annual screening mammography should begin at age 40, according to a study published in the American Journal of Roentgenology.
Researchers from Weill Cornell Medical College in New York, NY, performed a retrospective cohort study to determine the primary endpoint of determining the rate of detection of breast cancer and associated prognostic features in women aged 40 to 44 and 45 to 49 . The focus was on cancer detection rate, pathologic findings, and risk factors.
The researchers obtained data from 32,762 screenings performed from June 2014 to May 2016; 808 biopsies were recommended, resulting in detection of 224 cancers for a cancer detection rate of 6.84 per 1,000 screens.
Cancers detected by age group:
|40 to 49 years||18.8%|
|50 to 59 years||21.8%|
|60 to 69 years||32.6%|
|70 to 79 years||21.4%|
The women in the 40-to-49-year age group were subdivided into 40 to 44 years, and 45 to 49 years. The women in the younger group underwent 5,481 (16.7%) screens, had 132 biopsies recommended, and had 20 breast cancers detected for a cancer detection rate of 3.6 per 1,000. Women who were 45 to 49 years old underwent 5,319 (16.2%) screens, had 108 biopsies recommended, and had 22 breast cancers detected, for a cancer detection rate of 4.1 per 1,000.
The women in the 40-to-44-year group had 8.9% of all screen-detected breast cancers and women 45–49 years old had 9.8%. Of these, only 15% of the women with detected cancers in the younger group and 32% in the older group had a first-degree relative with breast cancer (40–44 years, 15%; 45–49 years, 32%), and only 5% of both groups had a BRCA mutation. Over 60% of the cancers were invasive.
The researchers concluded that women in their forties had 18.8% of all screen-detected breast cancers, with similar incidences of screen-detected breast cancer between women from 40 to 44 years and those 45 to 49 years. These findings support a similar recommendation for both cohorts and the American College of Radiology recommendation of annual screening mammography starting at age 40.