%0 Journal Article
%T Involution of Breast Lobules, Mammographic Breast Density and Prognosis Among Tamoxifen-Treated Estrogen Receptor-Positive Breast Cancer Patients
%A Amy Berrington de Gonzalez
%A Andrew Glass
%A Donna Butcher
%A Erin J. Aiello Bowles
%A Gretchen L. Gierach
%A Jonine D. Figueroa
%A Lawrence Sternberg
%A Louise A. Brinton
%A Maeve Mullooly
%A Mark E. Sherman
%A Renata Cora
%A Robert N. Hoover
%A Ruth M. Pfeiffer
%A Sarah J. Nyante
%A Shaoqi Fan
%A Sheila Weinmann
%J Journal of Clinical Medicine | An Open Access Journal from MDPI
%D 2019
%R https://doi.org/10.3390/jcm8111868
%X Mammographic breast density (MD) reflects breast fibroglandular content. Its decline following adjuvant tamoxifen treated, estrogen receptor (ER)-positive breast cancer has been associated with improved outcomes. Breast cancers arise from structures termed lobules, and lower MD is associated with increased age-related lobule involution. We assessed whether pre-treatment involution influenced associations between MD decline and risk of breast cancer-specific death. ER-positive tamoxifen treated patients diagnosed at Kaiser Permanente Northwest (1990每2008) were defined as cases who died of breast cancer (n = 54) and matched controls (remained alive over similar follow-up; n = 180). Lobule involution was assessed by examining terminal duct lobular units (TDLUs) in benign tissues surrounding cancers as TDLU count/mm2, median span and acini count/TDLU. MD (%) was measured in the unaffected breast at baseline (median 6-months before) and follow-up (median 12-months after tamoxifen initiation). TDLU measures and baseline MD were positively associated among controls (p < 0.05). In multivariable regression models, MD decline (≡10%) was associated with reduced risk of breast cancer-specific death before (odds ratio (OR): 0.41, 95% CI: 0.18每0.92) and after (OR: 0.41, 95% CI: 0.18每0.94) adjustment for TDLU count/mm2, TDLU span (OR: 0.34, 95% CI: 0.14每0.84), and acini count/TDLU (OR: 0.33, 95% CI: 0.13每0.81). MD decline following adjuvant tamoxifen is associated with reduced risk of breast cancer-specific death, irrespective of pre-treatment lobule involution. View Full-Tex
%U https://www.mdpi.com/2077-0383/8/11/1868