Does family history predict the age at onset of new breast cancers in BRCA1 and BRCA2 mutation‐positive families?

Women who carry BRCA mutations are advised to begin breast cancer screening based on the age-specific risks of breast cancer development. It is not clear to what extent the family history of breast cancer influences age of onset. We evaluated the use of family history to predict the age of breast cancer onset in BRCA mutation carriers. Pedigrees from an Ontario-based registry were reviewed to identify the index case of breast cancer (most …