Mammographic Density Affects Breast Cancer Screening Quality

Abstract

The identification of a mass on mammography（MMG）is difficult if the breast is dense. MMG density can be classified into dense（heterogenous and extremely dense tissue）and non- dense（fatty and scattered fibroglandular tissue）. We compared the demographic data and quality of breast cancer screening among subjects who underwent MMG screening between January ２０１５and October２０１６as well as the false-positive rates among subjects without breast cancer. During this period, １３４ patients underwent breast-conserving surgery, which was intended for １０３６ patients without breast cancer. Subjects with or without breast cancer were examined and classified into non-dense and dense groups. Among the patients who underwent surgery, ４６ and ８８ patients had non-dense and dense breasts, respectively. The median age of the patients was ６５ years（range, ３６-９１ years）and ５３ years（range, ３７-７６ years）in the dense and non-dense groups, respectively（P ＜０.０５）. The median diameter of the mass was １５ mm in both groups（n.s.）. Seventy-six（８４.４％）and ４４ patients（９５.７％）in the dense and non-dense groups, respectively, had greater than category ３ lesions. Other MMG findings for breast cancer were also investigated, and architectural distortion was prominent in the dense group, whereas masses were more clearly visualized in the non-dense group. The false-positive rate in the dense group（８９ cases, １２.２％）was higher than that in the non-dense group（１７cases,５.６％）. These findings suggest that dense breast tissue lowers the sensitivity and specificity of MMG screening, and special attention should be given to architectural distortions among patients with dense breasts.