Reduced risk of breast cancer persists after cessation of conjugated equine estrogen therapy
TUESDAY, April 5 (HealthDay News) -- Among postmenopausal women with prior hysterectomy, cessation of conjugated equine estrogen (CEE) therapy reduces the risk of stroke, and the risk of breast cancer remains reduced, according to a study to be published on April 6 in the Journal of the American Medical Association.
Andrea Z. LaCroix, Ph.D., from the Fred Hutchinson Cancer Research Center in Seattle, and colleagues examined postintervention health outcomes associated with CEE treatment in participants of the Women's Health Initiative Trial. Postmenopausal women with prior hysterectomy were randomized to receive either 0.625 mg/day CEE or placebo for 5.9 years. The trial was stopped early, but follow-up continued for women who provided written consent. Primary outcomes measured were coronary heart disease (CHD) and invasive breast cancer after an average follow-up of 10.7 years.
The investigators found that the annualized postintervention risk for CHD, and total mortality for women assigned to CEE was similar to controls (hazard ratio [HR], 0.97 and 1.00, respectively). Postintervention annualized risk for breast cancer was 0.26 percent in the CEE treatment group, compared to 0.34 percent in controls, and this persisted over the entire follow-up period (HR, 0.75 and 0.77, respectively). The increased risks of stroke, seen during the intervention phase, were not present during the postintervention phase. Risk of pulmonary embolism and hip fractures was similar to controls during the entire follow-up period.
"Several patterns of health risks and benefits seen during the intervention period were not maintained during the postintervention period, while other trends persisted," the authors write.
Several authors disclosed financial ties to pharmaceutical companies, including Wyeth Ayerst, which provided the study drugs.
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