Family History of Breast Cancer, Breast Density, and Breast Cancer Risk in a U.S. Breast Cancer Screening Population

Abstract

Background The utility of incorporating detailed family history into breast cancer risk prediction hinges on its independent contribution to breast cancer risk. We evaluated associations between detailed family history and breast cancer risk while accounting for breast density. Methods We followed 222,019 participants aged 35–74 in the Breast Cancer Surveillance Consortium, of whom 2,456 developed invasive breast cancer. We calculated standardized breast cancer risks within joint strata of breast density and simple (1st-degree female relative) or detailed (1st-degree, 2nd-degree, or 1st- and 2nd-degree female relative) breast cancer family history. We fit log-binomial models to estimate age-specific breast cancer associations for simple and detailed family history, accounting for breast density. Results Simple 1st-degree family history was associated with increased breast cancer risk compared with no 1st-degree history (RR=1.5, 95%CI 1.0–2.1 at age 40; RR=1.5, 95%CI 1.3–1.7 at age 50; RR=1.4, 95%CI 1.2–1.6 at age 60; RR=1.3, 95%CI 1.1–1.5 at age 70). Breast cancer associations with detailed family history were strongest for women with 1st- and 2nd-degree family history compared with no history (RR=1.9, 95%CI 1.1–3.2 at age 40); this association weakened in higher age groups (RR=1.2, 95%CI 0.88–1.5 at age 70). Associations did not change substantially when adjusted for breast density. Conclusion Even with adjustment for breast density, a history of breast cancer in both 1st- and 2nd-degree relatives is more strongly associated with breast cancer than simple 1st-degree family history. Impact Future efforts to improve breast cancer risk prediction models should evaluate detailed family history as a risk factor.

Assessment of common risk factors and validation of the Gail model for breast cancer: A hospital-based study from Western India

“…We also found that patient with a family history of breast carcinoma in first degree relatives has increased risk of breast cancer. This finding is in line with the previous reports from other studies from India and abroad [ 14 15 16 ]. Atypical hyperplasia is a premalignant condition for breast carcinoma and leads to an increased incidence of breast cancer.…”

Investigation Risk Factors for Breast Cancer in Women: A Case–Control Study in Arak, Iran

“…As shown in Table 3, the hypertension was not associated with breast cancer risk. Our data is consistent with studies conducted by Wang et al [61] and Sun et al [62]. One cohort study, one nested case-control study and ten case-control studies showed that hypertension is associated with increased risk of breast cancer [63].…”

Familial risk of breast cancer by dynamic, accumulative, and static definitions of family history

“…Family history is an important risk factor for breast cancer, a disease that accounts for approximately 25% of all cancers diagnosed in women . Approximately 15% of all breast cancers are diagnosed among women with a family history of the disease . Women with a family history of breast cancer are at a 2 to 4 times increased risk of breast cancer depending on the number of affected relatives and the age at which the relatives were diagnosed .…”

“…To the best of our knowledge, the majority of studies assessing the familial risk of cancers, including breast cancer, take family history as a marker of familial predisposition, and as constant during the lifetime of an individual. Common approaches that are used to assign family history status include having at least 1 affected first‐degree relative (FDR), the number and type of affected FDRs, or a detailed combination of FDRs and second‐degree relatives (SDRs) . In register‐based studies, family history often has been assessed and assigned (as a static variable) at a single point in time, typically at the end of follow‐up, an approach that does not take into account the timing of events .…”