A new Swedish study has reported that women with a family history of breast cancer are more likely to get breast cancer at a younger age. The study compared the differences in the age of onset and breast cancer mortality between women with a family history of breast cancer and those without. The authors used data from the Swedish Family-Cancer Database to calculate cumulative breast cancer risk and mortality due to breast cancer associated with family history. The age to reach the same cumulative incidence of breast cancer as women without family history was lower, especially when the older relative was diagnosed at a relatively young age. For example, daughters of mothers who were diagnosed with breast cancer before age 40 were found to reach the level of risk that women lacking a family history had at the age of 50 approximately 12.3 years earlier. On the other hand, daughters of mothers who were diagnosed at age 82 and older reached the level of risk of women aged 50 without a family history approximately 3.3 years earlier. The results for death from breast cancer were similar. The authors conclude that women having a mother or sister with breast cancer are diagnosed and die at younger ages than women without a family history. The differences depend on the diagnostic age of the affected relative.

These findings and the findings of previous studies support recommendations for early mammograms and other types of breast cancer screening of women with affected family members. While mammograms themselves may increase breast cancer risk over time, there are strategies that can be adopted to mitigate the additional radiation risk.