Emerging Trends in Family History of Breast Cancer and Associated Risk
Menée aux Etats-Unis à partir de données de cohortes incluant 1 170 900 patientes atteintes d'un cancer du sein sur la période 1996-2012, 23 400 patientes et 26 460 témoins sur la période 1987-2007, cette étude analyse la proportion de patientes âgées entre 40 et 74 ayant des antécédents familiaux au premier degré de cancer du sein, puis évalue l'association entre des antécédents familiaux de cancer du sein et le risque de développer la maladie
Background: Increase in breast cancer incidence associated with mammography screening diffusion may have attenuated risk associations between family history and breast cancer.
Methods: The proportions of women aged 40-74 years reporting a first-degree family history of breast cancer were estimated in the Breast Cancer Surveillance Consortium cohort (BCSC, N=1,170,900; 1996-2012) and the Collaborative Breast Cancer Study (CBCS; cases N=23,400; controls N=26,460; 1987-2007). Breast cancer (ductal carcinoma in situ and invasive) relative risk estimates and 95% confidence intervals (CI) associated with family history were calculated using multivariable Cox proportional hazard and logistic regression models.
Results: The proportion of women reporting a first-degree family history increased from 11% in the 1980s to 16% in 2010-13. Family history was associated with a >60% increased risk of breast cancer in the BCSC (hazard ratio=1.61;95%CI=1.55-1.66) and CBCS (odds ratio=1.64;95%CI=1.57-1.72). Relative risks decreased slightly with age. Consistent trends in relative risks were not observed over time or across stage of disease at diagnosis in both studies, except among older women (60-74) where estimates were attenuated from about 1.7 to 1.3 over the last 20 years (P-trend=0.08 for both studies).
Conclusion: Although the proportion of women with a first-degree family history of breast cancer increased over time and by age, breast cancer risk associations with family history were nonetheless fairly constant over time for women under age 60.
Implication: First-degree family history of breast cancer remains an important breast cancer risk factor, especially for younger women, despite its increasing prevalence in the mammography screening era.%U http://cebp.aacrjournals.org/content/cebp/early/2017/10/06/1055-9965.EPI-17-0531.full.pdf
Cancer Epidemiology Biomarkers & Prevention , résumé, 2016