Family history of breast cancer as a second primary malignancy in relatives : a nationwide cohort study
BACKGROUND: With the increasing number of breast cancer (BC) diagnosed as a second primary malignancy after a first primary non-breast cancer (BCa-2), it is unclear about the familial risk of BC among women with a first-degree relative (FDR, parents or siblings) affected by a BCa-2.METHODS: In this Swedish nationwide cohort study, 5315 women with a FDR affected by BCa-2 and 115,048 women with a FD