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 regimen.
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 WebMD.
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 flashes.
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.