Family history of breast cancer in relation to tumor characteristics and mortality in a population-based study of young women with invasive breast cancer
Cette étude de cohorte en population américaine incluant 1 260 participantes, diagnostiquées avec un cancer invasif du sein avant l'âge de 46 ans, évalue l'impact d'une histoire familiale de cancer du sein sur les caractéristiques de la tumeur et sur la survie des patientes
BACKGROUND. Inherited predisposition may be associated with distinctive breast cancer phenotypes and/or mortality. Past studies have had inconsistent results; few have been population-based and little is known about the contributions of screening and treatment. METHODS. Within a population-based cohort of 1260 non-adopted women diagnosed with invasive breast cancer before age 46, we assessed how family history of breast cancer relates to mortality and tumor characteristics. Analyses were repeated excluding BRCA1/BRCA2 carriers. Medical records were reviewed for treatment history and tumors were assessed for histopathologic features and selected markers. Cox proportional hazard modeling was used to assess the risk of dying in relation to family history; logistic regression was used to assess the association of family history to tumor characteristics. RESULTS. Compared to women with no family history, women with first-degree family history of breast cancer had a 40% reduction (95% CI 0.5-0.8) in the risk of dying. Mortality in women with only a second-degree family history was similar to that in women with no family history. The risk of dying was further reduced in those with a greater number of affected relatives. These relationships did not appear to be attributable to differences in screening, detection method, or treatment. Tumors in women with a first-degree family history had generally more favorable prognostic profiles. CONCLUSION. Our findings suggest that breast cancer patients with a first-degree family history, compared to their counterparts without such a profile, may have a better prognosis. Further research is needed to identify factors that might underlie these observations.