April 6, 2011 - Among
postmenopausal women with a prior hysterectomy and who had used estrogen
therapy for about 6 years and then stopped, longer-term follow-up
indicates that the risk of breast cancer was reduced, regardless of age.
Health outcomes were, however, more favorable for younger compared with
older women for CHD, heart attack, colorectal cancer, total mortality,
and a global index of chronic diseases.
Generally, however, the
report in the April 6 issue of the Journal of the American Medical
Association (JAMA) finds the increased risk of stroke seen during the therapy
intervention period had dissipated, the decreased risk of hip fracture
was not maintained.
"The Women's Health
Initiative (WHI) Estrogen-Alone Trial was a double-blind,
placebo-controlled, randomized clinical trial evaluating the effects of
conjugated equine estrogens (CEE) on chronic disease incidence among
postmenopausal women with prior hysterectomy," the authors write.
The trial intervention
was stopped 1 year early after an average of 7.1 years of follow-up
because of an increased risk of stroke and little likelihood of altering
the balance of risk to benefit by the planned termination date. All
previous reports of this trial were limited to health outcomes occurring
during the intervention phase, according to background information in
the article.
Researchers led by
Andrea Z. LaCroix, Ph.D., of the Fred Hutchinson Cancer Research Center,
Seattle, analyzed data on health outcomes after the CEE intervention
through an average of 10.7 years of follow-up, through August 2009.
The intervention phase
was a clinical trial of 0.625 mg/d of CEE compared with placebo in
10,739 U.S. postmenopausal women, ages 50 to 79 years with prior
hysterectomy. Follow-up continued after the planned trial completion
date among 7,645 surviving participants (78 percent) who provided
written consent.
The researchers found
that the risk for coronary heart disease (CHD) during the
post-intervention follow-up period was similar to that observed during
the intervention.
The increased stroke
risk seen during the intervention phase was not present during the
post-intervention phase (0.36% for 66 women) in the CEE group vs. 0.41
percent (77 women)] in the placebo group.
Similarly, the increase
in deep vein thrombosis and pulmonary embolism with CEE
use compared with placebo during the intervention phase was not
maintained during the post-intervention phase.
The risk of invasive
breast cancer in women randomized to CEE vs. placebo was similar
during the intervention and post-intervention phases. "Consequently, a
statistically significant lower cumulative breast cancer incidence of
0.27 percent was seen in the CEE group (n = 151) compared with 0.35
percent in the placebo group (n=199).
Colorectal cancer
incidence did not differ between the women in the CEE group and the
placebo group during the intervention or post-intervention periods," the
authors write.
They add that the
reduced hip fracture risk seen during the intervention phase with
CEE was not maintained in the post-intervention phase, with hip fracture
incidence slightly higher in the CEE group compared with the placebo
group during the post-intervention phase. Randomization to CEE did not
influence total mortality during the intervention or
post-intervention phase.
Health outcomes were
more favorable for younger compared with older women for CHD, heart
attack, colorectal cancer, total mortality, and a global index of
chronic diseases.
"Our results emphasize
the need to counsel women about hormone therapy differently depending on
their age and hysterectomy status, wrote the researchers.
A postmenopausal woman
who has had a hysterectomy and is considering initiation of CEE should
be counseled about the increased risks of venous thromboembolism and a
stroke during treatment, which diminish with treatment cessation.
Among younger women, no
new safety concerns emerged and some risk reductions became apparent
during the post-intervention period.
Among older women,
risks of colorectal cancer, death, and the global index of chronic
diseases were elevated over the cumulative follow-up period.
The risks and benefits
of CEE use for periods of longer than 5 to 6 years cannot be inferred
from these data for any age group. Mechanisms underlying the reduced
risks of breast cancer in all women, and coronary events in younger but
not older women, warrant further study," the authors conclude.
Editorial: Short-term Use of Unopposed Estrogen
- A Balance of Inferred Risks and Benefits
In an accompanying
editorial, Emily S. Jungheim, M.D., M.S.C.I., and Graham A. Colditz,
M.D., Dr.P.H., of the Washington University School of Medicine, St.
Louis, write that findings from the WHI have been an important guide for
clinicians on the overall risks and benefits of hormone therapy (HT).
"There may still be a
role for short-term use of unopposed estrogen for treating some women
with menopausal symptoms, but this role may be vanishing as existing and
emerging data continue to be better understood in terms of application
to patients, according to an accompanying editorial by Emily S.
Jungheim, M.D., M.S.C.I., and Graham A. Colditz, M.D., Dr.P.H., of the
Washington University School of Medicine, St. Louis.
Findings from the WHI
have been an important guide for clinicians on the overall risks and
benefits of hormone therapy (HT), they add.
In the meantime, the
symptoms of menopause can be significant and require thoughtful
management. This would include careful consideration and discussion of
the long-term risks and short-term benefits of HT as well as thorough
discussion of other treatment strategies and optimization of lifestyle
to ensure the best outcomes for women in the many years they should
enjoy post-menopause."
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