One age fits one.

If you have a relative with a history of breast cancer, when is the right age to start mammogram screening? This Swedish nationwide cohort study included over 5 million women born after 1932 who had at least one known first-degree relative in the cohort. Among these, 2% were diagnosed with breast cancer. The majority (86%) did not have a family history of breast cancer among first or second degree relatives at the time of diagnosis. This large data set then was used to determine the age at which breast cancer risk was high enough to merit screening based upon the extent of family history of breast cancer. Using a screening benchmark of age 50 for screening based on a 2% ten-year cumulative risk of breast cancer, they estimated that a woman with multiple first-degree relatives with breast cancer had sufficient risk for screening well before age 40. In fact, for women whose youngest first-degree relative was diagnosed before age 50, the ideal age for screening was 27 years and 36 years for those whose youngest first-degree relative was over 50. TBL: The appropriate age to initiate breast cancer screening should be informed by family history. | Mukama, JAMA Oncol 2019