Assessment of mammographic density before and after first full-term pregnancy.
Mammographic density (MD) has consistently been found as one of the strongest breast cancer risk factors. In our study, both qualitative and quantitative density measurements were performed in a hospital-based group of premenopausal women before and after first full-term pregnancy providing an opportunity for direct evaluation of the effects of one pregnancy on MD. Mammograms were obtained from 23 women before and after first full-term pregnancy and from 28 nulliparous controls. MD was determined by a standard qualitative assessment method using the Breast Imaging Reporting and Data System, and a quantitative computer-based threshold method (0-100%). The mean age at mammography before and after pregnancy was 31 and 34 years, respectively, with a mean difference of 40 months between mammographies. The quantitative density assessment showed a significant reduction in relative MD after pregnancy of 12 percentage points (8.6-15.4), compared with 3.1 (0.0-6.2) in the nulliparous control group (P<0.001). A reduction in MD of more than 10% was seen in 52% of the patients, compared with 18% of the controls. The qualitative density assessment confirmed a reduction in MD after pregnancy by one Breast Imaging Reporting and Data System category (P=0.02). This longitudinal study showed that MD can be influenced by one full-term pregnancy. This effect was seen with both quantitative and qualitative assessment methods. It may be hypothesized that breast cancer risk reduction associated with pregnancy is mediated through a direct reduction of MD, and MD assessment might be incorporated in individualizing risk assessment and prevention.
Loehberg
Christian R
CR
Department of Obstetrics and Gynecology, University Breast Center Franconia, Erlangen, Germany.
Heusinger
Katharina
K
Jud
Sebastian M
SM
Haeberle
Lothar
L
Hein
Alexander
A
Rauh
Claudia
C
Bani
Mayada R
MR
Lux
Michael P
MP
Schrauder
Michael G
MG
Bayer
Christian M
CM
Helbig
Cosima
C
Grolik
Ronald
R
Adamietz
Boris
B
Schulz-Wendtland
Ruediger
R
Beckmann
Matthias W
MW
Fasching
Peter A
PA
D000328:Adult; D001940:Breast / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008327:Mammography; D010298:Parity; D011247:Pregnancy / Q000502:physiology*; D012307:Risk Factors; D047929:Term Birth; D013997:Time Factors