Abstract
Background: Estrogens stimulate proliferation of breast epithelium and may therefore increase the risk of benign proliferative breast disease, a condition that is associated with increased risk of breast cancer. We tested the effect of conjugated equine estrogen (CEE) on risk of benign proliferative breast disease in the Women's Health Initiative (WHI) randomized controlled trial. Methods: In the WHI CEE trial, 10739 postmenopausal women were randomly assigned to 0.625 mg/d of CEE or to placebo. Baseline and annual breast examinations and mammograms were required. We identified women in the trial who reported breast biopsies that were free of cancer, obtained the associated histological sections, and subjected them to standardized central review. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). All statistical tests were two-sided. Results: A total of 232 incident cases of benign proliferative breast disease were ascertained during follow-up (average duration, 6.9 years), with 155 in the CEE group and 77 in the placebo group. Use of CEE was associated with a more than two-fold increase in the risk of benign proliferative breast disease (HR = 2.11, 95% CI = 1.58 to 2.81). For benign proliferative breast disease without atypia, the HR was 2.34 (95% CI = 1.71 to 3.20), whereas for atypical hyperplasia, it was 1.12 (95% CI = 0.53 to 2.40). Risk varied little by levels of baseline characteristics. Conclusion: Use of 0.625 mg/d of CEE was associated with a statistically significant increased risk of benign proliferative breast disease.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 563-571 |
| Number of pages | 9 |
| Journal | Journal of the National Cancer Institute |
| Volume | 100 |
| Issue number | 8 |
| DOIs | |
| State | Published - 2008 |
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ASJC Scopus subject areas
- Cancer Research
- Oncology
Cite this
Conjugated equine estrogen and risk of benign proliferative breast disease : A randomized controlled trial. / Rohan, Thomas E.; Negassa, Abdissa; Chlebowski, Rowan T.; Habel, Laurel; McTiernan, Anne; Ginsberg, Mindy S.; Wassertheil-Smoller, Sylvia; Page, David L.
In: Journal of the National Cancer Institute, Vol. 100, No. 8, 2008, p. 563-571.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Conjugated equine estrogen and risk of benign proliferative breast disease
T2 - A randomized controlled trial
AU - Rohan, Thomas E.
AU - Negassa, Abdissa
AU - Chlebowski, Rowan T.
AU - Habel, Laurel
AU - McTiernan, Anne
AU - Ginsberg, Mindy S.
AU - Wassertheil-Smoller, Sylvia
AU - Page, David L.
PY - 2008
Y1 - 2008
N2 - Background: Estrogens stimulate proliferation of breast epithelium and may therefore increase the risk of benign proliferative breast disease, a condition that is associated with increased risk of breast cancer. We tested the effect of conjugated equine estrogen (CEE) on risk of benign proliferative breast disease in the Women's Health Initiative (WHI) randomized controlled trial. Methods: In the WHI CEE trial, 10739 postmenopausal women were randomly assigned to 0.625 mg/d of CEE or to placebo. Baseline and annual breast examinations and mammograms were required. We identified women in the trial who reported breast biopsies that were free of cancer, obtained the associated histological sections, and subjected them to standardized central review. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). All statistical tests were two-sided. Results: A total of 232 incident cases of benign proliferative breast disease were ascertained during follow-up (average duration, 6.9 years), with 155 in the CEE group and 77 in the placebo group. Use of CEE was associated with a more than two-fold increase in the risk of benign proliferative breast disease (HR = 2.11, 95% CI = 1.58 to 2.81). For benign proliferative breast disease without atypia, the HR was 2.34 (95% CI = 1.71 to 3.20), whereas for atypical hyperplasia, it was 1.12 (95% CI = 0.53 to 2.40). Risk varied little by levels of baseline characteristics. Conclusion: Use of 0.625 mg/d of CEE was associated with a statistically significant increased risk of benign proliferative breast disease.
AB - Background: Estrogens stimulate proliferation of breast epithelium and may therefore increase the risk of benign proliferative breast disease, a condition that is associated with increased risk of breast cancer. We tested the effect of conjugated equine estrogen (CEE) on risk of benign proliferative breast disease in the Women's Health Initiative (WHI) randomized controlled trial. Methods: In the WHI CEE trial, 10739 postmenopausal women were randomly assigned to 0.625 mg/d of CEE or to placebo. Baseline and annual breast examinations and mammograms were required. We identified women in the trial who reported breast biopsies that were free of cancer, obtained the associated histological sections, and subjected them to standardized central review. Cox proportional hazards models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). All statistical tests were two-sided. Results: A total of 232 incident cases of benign proliferative breast disease were ascertained during follow-up (average duration, 6.9 years), with 155 in the CEE group and 77 in the placebo group. Use of CEE was associated with a more than two-fold increase in the risk of benign proliferative breast disease (HR = 2.11, 95% CI = 1.58 to 2.81). For benign proliferative breast disease without atypia, the HR was 2.34 (95% CI = 1.71 to 3.20), whereas for atypical hyperplasia, it was 1.12 (95% CI = 0.53 to 2.40). Risk varied little by levels of baseline characteristics. Conclusion: Use of 0.625 mg/d of CEE was associated with a statistically significant increased risk of benign proliferative breast disease.
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U2 - 10.1093/jnci/djn075
DO - 10.1093/jnci/djn075
M3 - Article
C2 - 18398105
AN - SCOPUS:43149099456
VL - 100
SP - 563
EP - 571
JO - Journal of the National Cancer Institute
JF - Journal of the National Cancer Institute
SN - 0027-8874
IS - 8
ER -