Emerging Trends in Family History of Breast Cancer and Associated Risk.

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.

Investigators
Abbreviation
Cancer Epidemiol. Biomarkers Prev.
Publication Date
2017-10-06
Pubmed ID
28986348
Medium
Print-Electronic
Full Title
Emerging Trends in Family History of Breast Cancer and Associated Risk.
Authors
Shiyanbola OO, Arao RF, Miglioretti DL, Sprague BL, Hampton JM, Stout NK, Kerlikowske K, Braithwaite D, Buist DSM, Egan KM, Newcomb PA, Trentham-Dietz A