Distribution of dense breasts using screening mammography in Korean women: a retrospective observational study.
OBJECTIVE
This retrospective observational study evaluated the distribution of dense breasts by age group among healthy Korean women.


METHODS
Participants were women aged 30 years and older who voluntarily underwent screening mammography between January 2007 and December 2011. Women who received the Breast Imaging Reporting and Data System for mammographic density of 3 or 4 were defined as having dense breasts. The proportion of women with dense breasts (PDB, %) was calculated by dividing the number of participants with dense breasts by the total number of participants.


RESULTS
Among the 231,058 women who participated, 78.15% were classified as having dense breasts. PDB was highest in the youngest age group (PDB=94.87%) and lowest in the oldest age group. The greatest difference in PDB between adjacent age groups was observed in the group aged 60-64 years.


CONCLUSIONS
The results show that the proportion of dense breasts by age group increased in all age groups, except in those aged 35-39 years. These findings suggest an association between the age distribution of dense breasts and trends in breast cancer incidence. Further studies are needed to estimate the change in breast cancer incidence rate by age and the accumulation of fatty breast tissue in Korean women.
Department of Preventive Medicine, Jeju National University School of Medicine, Jeju, Korea.
Jong-Myon
JM
Bae
Korea Medical Institute, Seoul, Korea.
Sang Yop
SY
Shin
Department of Preventive Medicine, Jeju National University School of Medicine, Jeju, Korea.
Eun Hee
EH
Kim
Severance Hospital, Seoul, Korea.
Yoon-Nam
YN
Kim
Department of Preventive Medicine, Yonsei University College of Medicine, Seoul, Korea.
Chung Mo
CM
Nam
Breast neoplasms; Early detection of cancer; Mammography; Mass screening