Mammography screening women regularly at age 50 results in many women in their 40s not being diagnosed with breast cancer.
Waiting until women are 50 years old before screening them for breast cancer delays detection of up to 20% of cancers among women of average risk for the disease, according to a study published in the American Journal of Roentgenology.
Researchers from Weill Cornell Medical College and New York Presbyterian Hospital–Weill Cornell Medical Center, both in New York, NY, performed a retrospective cohort study to determine the rate of detection of breast cancer and associated prognostic features in women 40 to 44 and 45 to 49 years old.
The researchers obtained the results of 32,762 screening mammograms; 808 biopsies were recommended based on the screenings. These biopsies yielded 224 breast cancers, for a cancer detection rate of 6.84 per 1,000 screening:
• Women 40 to 49 years old had 18.8% of cancers detected
• Women 50 to 59 years old had 21.8% of cancers detected
• Women 60 to 69 years old had 32.6% of cancers detected
• Women 70 to 79 years old had 21.4% of cancers detected
Among the women in the 40- to 44-year-old age group, there were 5,481 (16.7%) screens, with 132 biopsies recommended, and 20 breast cancers detected, for a cancer detection rate of 3.6 per 1,000 screenings. Women in the 45-to 49-year-old group underwent 5,319 (16.2%) screens, had 108 biopsies recommended, and had 22 breast cancers detected, for a cancer detection rate of 4.1/1,000. These findings showed that women from age 40 to 44 had 8.9% of all screen-detected breast cancers and women who were age 45 to 49 had 9.8%. Of these, only a small percentage of women with detected cancers had a first-degree relative with breast cancer (15% in the younger group [ages 40-44] and 32 percent in the older group) or a BRCA mutation (5% in the younger group and 5% in the older group). Over 60%of the cancers were invasive.
The researchers concluded that since women in their forties had 18.8%of all screen-detected breast cancers, with the younger and older cohorts having similar incidences of screen-detected breast cancer, annual screening mammograms should begin at age 40.