ABSTRACT
OBJECTIVE: The purpose of this study was to review screening mammograms obtained in one practice with the primary endpoint of determining the rate of detection of breast cancer and associated prognostic features in women 40-44 and 45-49 years old. MATERIALS AND METHODS: The retrospective cohort study included women in their 40s with breast cancer detected at screening from June 2014 through May 2016. The focus was on cancer detection rate, pathologic findings, and risk factors. RESULTS: A total of 32,762 screens were performed, and 808 biopsies were recommended. These biopsies yielded 224 breast cancers (cancer detection rate, 6.84 per 1000 screens). Women 40-49 years old had 18.8% of cancers detected; 50-59 years, 21.8%; 60-69 years, 32.6%; and 70-79 years, 21.4%. Among the 40- to 49-year-old women, women 40-44 years old underwent 5481 (16.7%) screens, had 132 biopsies recommended, and had 20 breast cancers detected (cancer detection rate, 3.6/1000). Women 45-49 years old underwent 5319 (16.2%) screens, had 108 biopsies recommended, and had 22 breast cancers detected (cancer detection rate, 4.1/1000). Thus, women 40-44 years old had 8.9% and women 45-49 years old had 9.8% of all screen-detected breast cancers. Of these only a small percentage of women with detected cancers had a first-degree relative with breast cancer (40-44 years, 15%; 45-49 years, 32%) or a BRCA mutation (40-44 years, 5%; 45-49 years, 5%), and over 60% of the cancers were invasive. CONCLUSION: Women 40-49 years old had 18.8% of all screen-detected breast cancers. The two cohorts (40-44 and 45-49 years old) had similar incidences of screen-detected breast cancer (8.9%, 9.8%) and cancer detection rates within performance benchmark standards, supporting a similar recommendation for both cohorts and the American College of Radiology recommendation of annual screening mammography starting at age 40.
