Mammographic breast density and tolerance for short-term postmenopausal hormone therapy suspension.
BACKGROUND
Breast density tends to decrease when women stop taking hormone therapy (HT). Some women find HT cessation difficult to tolerate, possibly because of fluctuations in endogenous hormone levels and vasomotor symptoms. We hypothesized that women with dense breasts might have lower tolerance for short-term HT suspension than do women with fatty breasts.


METHODS
As part of the Radiologic Evaluation And breast Density (READ) trial, we randomly assigned 881 women aged 45-80 with a prior screening (index) mammogram to suspend HT for 1 or 2 months before their next screening (study) mammogram. We measured continuous breast density on index mammograms using computer-assisted thresholding. At study mammograms, women indicated tolerance for stopping HT from 1 (extremely difficult) to 7 (very easy). Using linear regression, we evaluated the association between index breast density and tolerance after cessation, adjusting for age, body mass index (BMI), HT type, randomization group, and vasomotor symptoms.


RESULTS
A higher percentage of breast density was associated with lower unadjusted mean tolerance scores (tolerance 4.27, 95% confidence interval [CI] 3.77-4.77 for women with > or =50% density, and 4.73, 95% CI 4.45-5.01 for women with <10% density, not a statistically significant difference). In adjusted analyses, neither percent breast density nor dense breast area was associated with tolerance for HT suspension.


CONCLUSIONS
Although HT use affects breast density, tolerance for suspending HT is not associated with breast density. Women with dense breasts have the greatest potential for decreases in density after HT cessation; they should tolerate stopping HT as well as women with fatty breasts.
Aiello Bowles
Erin J
EJ
Group Health Research Institute, Group Health Cooperative, Seattle, Washington 98101, USA. aiello.e@ghc.org
Anderson
Melissa L
ML
Reed
Susan D
SD
Newton
Katherine M
KM
Fitzgibbons
E Dawn
ED
Seger
Deborah
D
Buist
Diana S M
DS
D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D001940:Breast / Q000033:anatomy & histology*; D001941:Breast Diseases / Q000000981:diagnostic imaging*; D015914:Estrogen Replacement Therapy; D005260:Female; D019584:Hot Flashes; D006801:Humans; D008327:Mammography; D008875:Middle Aged; D017698:Postmenopause; D011856:Radiographic Image Enhancement; D014666:Vasomotor System / Q000187:drug effects / Q000503:physiopathology; D014861:Washington; D028761:Withholding Treatment