|
E-mail this page to a friend!
Senior Citizen Health & Medicine
Women in Halted 2002 Clinical Trial of Estrogen Plus
Progestin Still have Cancer Risk
Report in JAMA finds those on therapy with more
cancer than placebo-takers
| |
 |
|
| |
March 4, 2008 -
Women Remain at Risk for Breast Cancer Three Years After Stopping
Hormone Therapy in Women's Health Initiative Trial.
Watch
Video Windows Media |
|
March 4, 2008 Back in 2002 they stopped the
clinical trial where thousands of women were given the hormone therapy
of estrogen plus progestin, while others received a placebo, because
there were indications of increased breast cancer risk for those
receiving therapy. Now there is new evidence that these women may still
have an increased risk of cancer.
A follow-up study of the women will be published in
the March 5 issue of Journal of the American Medical Association.
Cardiovascular disease and fracture risks were
similar between the two groups, but women who took hormone therapy had
an overall higher global risk index reflecting the balance of risks and
benefits from a number of endpoints combined, including deaths.
The Womens Health Initiative (WHI) trial of
estrogen plus progestin, which included 16,608 postmenopausal women,
assessed whether conjugated equine estrogens (CEE) plus
medroxyprogesterone acetate (MPA) prevents heart disease and hip
fractures and increases the risk of breast cancer.
The trial was stopped in 2002 when data indicated
an increased risk of breast cancer and a failure to demonstrate an
overall health benefit of the therapy. Further analysis showed that
women in the CEE plus MPA group had higher risks of cardiovascular
disease (CVD), coronary heart disease (CHD), stroke and venous
thromboembolism and lower risks of fracture and colorectal cancer.
Gerardo Heiss, M.D., of the University of North
Carolina, Chapel Hill, N.C., and colleagues examined the risks and
benefits experienced by 15,730 trial participants who had follow-up,
from July 2002 to March 2005, after they stopped hormone therapy.
The researchers found that the annualized event
rates for the outcome all cancer was higher during the
post-intervention follow-up for the CEE plus MPA group (1.56 percent per
year [n = 281]) than the placebo group (1.26 percent per year [n =
218]).
This reflects a greater risk of invasive breast
cancer and other cancers in the CEE plus MPA group; the rates of
colorectal cancer did not differ significantly between the two groups;
rates of endometrial cancer were lower in the CEE plus MPA group.
Though risk of breast cancer remained elevated
during the follow-up, the risk was less than that experienced towards
the end of the trial period.
The risk of cardiovascular events after the
intervention were comparable, with an annualized rate of 1.97 percent in
the CEE plus MPA (343 events) and 1.91 percent in the placebo group (323
events), meaning that the increased risks found during the trial period
weakened after study drugs were stopped.
The risk of fractures during the post-intervention
follow-up was similar among women in both groups for each type of
fracture considered: hip, vertebral and other osteoporotic fractures.
This reflects a greater increase in the annualized
risk of fractures after the intervention in the women who had been
assigned to CEE plus MPA compared with women assigned to placebo,
particularly for hip and vertebral fractures. Thus, the protective
effects of CEE plus MPA previously evident during the trial were not
observed to carry over into the post-intervention phase..., the
researchers write.
During the post-intervention phase, the rate of
death from all causes was higher by 15 percent in the group originally
assigned to CEE plus MPA than in those assigned to placebo, but this
difference was not statistically significant.
A summary of the risks and benefits, the global
index, included outcomes for coronary heart disease, invasive breast
cancer, stroke, pulmonary embolism, endometrial cancer, colorectal
cancer, hip fracture and death due to other causes. The researchers
found that this measure was 12 percent higher in women randomly assigned
to receive CEE plus MPA compared with placebo and did not materially
change after the intervention was stopped.
This analysis of delayed and sustained health
benefits and risks following randomized allocation to CEE plus MPA vs.
placebo adds new information to inform the optimal use of postmenopausal
CEE plus MPA. Over the course of [an average of] 2.4 years from
termination of intervention with CEE plus MPA, rapid changes in hormone
therapyrelated risks and benefits were observed, as well as trends that
suggest that continued follow-up of the study participants of this trial
will be informative as regards possible delayed effects of CEE plus MPA,
the authors write.
Following termination of use of CEE plus MPA of
3.5 to 8.5 years, clinical vigilance seems warranted with respect to a
sustained higher risk of malignancies.
Click to More Senior News on the
Front Page
Copyright: SeniorJournal.com |
