After HRT, Some Health Risks Remain
Researchers Examine Pros and Cons of Hormone Replacement Therapy
March 4, 2008 -- For postmenopausal women who stop their hormone replacement
therapy (HRT), there is good news, bad news, and surprising news from a new
study that followed women for about two and a half years after they stopped the
On the plus side, some risks associated with the use of the combined
estrogen and progestin therapy disappear after the regimen is stopped,
including the increased risks of heart
disease, stroke, and blood clots in the lungs, the researchers found.
Unfortunately, the protective effects the hormones provide for hip fracture and
colorectal cancer also disappear once women quit the regimen.
Even two and a half years later, former HRT users still have an increased
risk of breast
cancer, which was discovered in the original study, called the Women's
Health Initiative (WHI). The increased risk after stopping the hormones,
however, was not statistically significant. And, in a surprise finding, former
HRT users also have a higher overall risk of getting cancers of many types
compared to nonusers, the researchers found.
Despite the new findings, including the surprise finding about cancer,
"the bottom line hasn't changed," says study researcher Gerardo Heiss,
MD, professor of epidemiology in the School of Public Health at the University
of North Carolina, Chapel Hill. The standard advice still applies, Heiss tells
And that is for women to take the lowest possible dose of HRT for the
shortest amount of time if they need it to quell bothersome symptoms such as hot
The study is published in the March 5 issue of The Journal of the
American Medical Association.
HRT and Health Risks: Study Details
Heiss and his colleagues followed up 15,730 of the 16,608 women who
participated in the original study, the WHI, designed to examine the health
effects of taking estrogen plus progestin in older women. The WHI study was
halted in 2002, after an average of 5.6 years of treatment, when researchers
found an increased breast cancer risk among those who took the hormone therapy
vs. those who took a placebo.
During the trial, they also found hormone users were at higher risk of heart
disease, stroke, and blood clots than were nonusers but at lower risk of
colorectal cancer and fractures.
In the new follow-up study, conducted from July 2002 to March 2005, Heiss'
team looked at the effect that stopping the hormones had on six outcomes: heart
disease, stroke, blood clots in the lungs (pulmonary embolism), invasive breast
cancer, colorectal cancer, and hip fracture.
HRT and Health Risks: Findings
"We have some good news," says Rowan T.Chlebowski, MD, PhD, a
medical oncologist at the Los Angeles Biomedical Research Institute in
California and another study researcher. "The cardiovascular disease risk
really ended once you stopped the hormones."