Breast cancer screenings are one of the most important tools in a woman's health arsenal. It's so important that women do self-exams once a month to check the health of their breasts, and stay on top of their annual exams with their OBGYN. Mammograms are a great screening tool, as well. The American Cancer Society says regular screenings should start at the age of 45, with women having the choice to start them at 40. For most women, this isn't an issue. But for women with a personal history of breast cancer or other risk factors, waiting until they're 40 to begin mammography screenings might not be the best course of action. Younger women with certain breast cancer risk factors, like “dense breasts, a personal history of breast cancer, or a family history of breast cancer” may be better served with earlier mammography screenings, according to a new study.

The study was presented at the annual meeting for the Radiological Society of North America (RSNA). Cindy S. Lee, M.D. is an assistant professor of radiology at NYU Langone Health in New York City and worked on the large-scale study. Dr. Lee and her team analyzed data from more than 5.7 screening mammograms done on 2.6 million women between January 2008 and December 2015.

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They compared the performance metrics of screenings among the women based on subgroups of age, risk factors, and breast density. They specifically focused on three risk factors: a personal history of breast cancer, a family history of breast cancer (any first-degree relative like a mom or sister), and dense breasts. The performance metrics they used cancer detection rate, recall rate, and positive predictive value for biopsy recommended (PPV2) and biopsy performed (PPV3). The recall rate refers to any woman who is called back for follow-up testing based on her mammogram results.

In the under 40 group, some women had an increased risk of breast cancer because of one of the risk factors that they focused on. Women in the 30-34 and 35-39 groups had similar detection recall and PPVs. But women in those groups who had at least one of the risk factors had significantly higher detection rates. So while women with average risk are probably fine to begin their mammograms after 40, the study shows that women who have at least one of the risk factors (personal history, family history, or dense breasts) are better served to start their mammography screenings at the age of 30.

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