Mammographic density and risk of breast cancer in Korean women. [Epub ahead of print]

Abstract

We carried out this study to evaluate the associationbetween mammographic density adjusted for age and BMIand early-onset breast cancer in Asian women. We recruited213 Korean patients with breast cancer (45% diagnosedbefore the age of 50 years) and 630 controls matched forage, menopausal status, and examination date. Thepercentage and absolute size of dense areas on digitalmammograms were measured using a computer-assistedthresholding technique (Cumulus). We carried out ananalysis using the conditional logistic regression modelwith adjustment for covariates. An increase by 1 SD in ageand BMI-adjusted absolute dense area and percentagedense area was associated with a 1.15-fold (95%confidence interval: 1.03, 1.29) and 1.20-fold (95%confidence interval: 1.06, 1.37) increased risk of breastcancer, respectively. These associations were stronger forpremenopausal disease (P=0.07 and 0.01, respectively)and for disease diagnosed before age 50 (P=0.07 and 0.02,respectively) than for postmenopausal disease (P=0.16and 0.23, respectively) or later onset disease (P=0.10and 0.10, respectively). There was no difference in theassociations with premenopausal versus postmenopausaland early-onset versus late-onset disease. After adjustingfor age and BMI, both a greater absolute dense area anda greater percentage dense area were associated withan increased risk of breast cancer, particularly at ayoung age