Family history of breast cancer and young age at diagnosis of breast cancer increase risk of second primary malignancies in women: a population-based cohort study

摘要

Among 152?600 breast cancer patients diagnosed during 1958–2000, there was a 22% increased risk of developing a second primary non-breast malignancy (standardised incidence ratio (SIR)=1.22; 95% confidence interval (CI): 1.19–1.24). The highest risk was seen for connective tissue cancer (SIR=1.78; 95% CI: 1.49–2.10). Increased risks were noted among women diagnosed with breast cancer before age 50. Oesophagus cancer and non-Hodgkin's lymphoma showed six- and four-fold higher risks, respectively, in women with a family history of breast cancer compared to those without in the 10-year follow-up period.