Grant: Operating Grant: Data Analysis Using Existing CDN Databases and Cohorts

Women who give birth have a 10-30% higher risk for developing breast cancer than women who never give birth. Breast cancer diagnosed in women aged 45 and younger within 10 years of giving birth is referred to as postpartum breast cancer (PPBC). Unfortunately, women diagnosed with PPBC are also more likely to die than women with breast cancer who never gave birth or even women who are diagnosed with breast cancer while pregnant. Interestingly, women who experience complications of pregnancy associated with inflammation are less likely to develop PPBC. The reasons why are not known, but we think that the placenta plays a role. Our project will be the first to describe how frequently PPBC occurs in Ontario. We think that our findings will help develop new guidelines for screening of breast cancer and will be important in promoting self-referral for breast cancer screening for women over 40 who have previously given birth. Our study will also be the first to study how the placenta may be involved in PPBC. Overall, our study will raise awareness of PPBC in Canada, support early screening for women who have given birth, and inform further research to develop ways to prevent or treat PPBC.