by Thi Xuan Mai Tran, Soyeoun Kim, Huiyeon Song, Boyoung
Park
The Breast: August 23, 2022
Background
This study investigated whether the association between
family history of breast cancer in first-degree relatives and breast cancer
risk varies by breast density.
Methods
Women aged 40 years and older who underwent screening
between 2009 and 2010 were followed up until 2020. Family history was assessed
using a self-reported questionnaire. Using Breast Imaging Reporting and Data
System (BI-RADS), breast density was categorized into dense breast
(heterogeneously or extremely dense) and non-dense breast (almost entirely
fatty or scattered areas of fibro-glandular). Cox regression model was used to
assess the association between family history and breast cancer risk.
Results
Of the 4,835,507 women, 79,153 (1.6%) reported having a
family history of breast cancer and 77,238 women developed breast cancer.
Family history led to an increase in the 5-year cumulative incidence in women
with dense- and non-dense breasts. Results from the regression model with and
without adjustment for breast density yielded similar HRs in all age groups,
suggesting that breast density did not modify the association between family
history and breast cancer. After adjusting for breast density and other
factors, family history of breast cancer was associated with an increased risk
of breast cancer in all three age groups (age 40–49 years: aHR 1.96, 95%
confidence interval [CI] 1.85–2.08; age 50–64 years: aHR 1.70, 95% CI
1.58–1.82, and age ≥65 years: aHR 1.95, 95% CI 1.78–2.14).
Conclusion
Family history of breast cancer and breast density are
independently associated with breast cancer. Both factors should be carefully
considered in future risk prediction models of breast cancer.
