Christian Pope, M.D.: Assessing the risks of hormone – replacement therapy

The Women's Health Initiative (WHI) was a major 15-year research program to address the most common causes of death, disability and poor quality of life in postmenopausal women cardiovascular disease, cancer, and osteoporosis.

The WHI was launched in 1991 and consisted of a set of clinical trials and an observational study, which together involved 161,808 generally healthy postmenopausal women.

The clinical trials were designed to test the effects of postmenopausal hormone therapy, diet modification, and calcium and vitamin D supplements on heart disease, fractures, and breast and colorectal cancer.

The hormone trial had two studies: the estrogen-plus-progestin study of women with a uterus and the estrogen-alone study of women without a uterus. (Women with a uterus were given progestin in combination with estrogen, a practice known to prevent endometrial cancer.) In both hormone therapy studies, women were randomly assigned to either the hormone medication being studied or to placebo. Those studies have now ended and the data has been analyzed.

Though it was found and generally agreed upon that women who took combined hormone replacement therapy (estrogen and progesterone) to lessen their hot flushes and insomnia symptoms increased their chances of breast cancer slightly, many studies suggested that the cancer that developed was less deadly.

New analysis of the data from the Women's Health Initiative now casts some doubt on those findings.

The study was recently published by the Journal of the National Cancer Institute, and concluded that the prognosis for patients with cancers on HRT is as severe as for other cancers in other words, those taking HRT have a higher mortality.

Nearly 70,000 postmenopausal women participated in trials as part of the Women's Health Initiative Project. In essence, those who took estrogen plus progestin had higher rates of breast cancer.

With a follow up of 11.3 years, the rate of breast cancer among hormone (estrogen plus progesterone) users was 0.6% compared with 0.42% for women not taking hormone replacement therapy. Particularly high risks were found for those who began HRT right at the time of menopause, rather than years after the onset of menopause.

These new results are consistent with the findings from the original randomized trial: survival after breast cancer was similar for both hormone users and non-users.

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Christian Pope, M.D.: Assessing the risks of hormone - replacement therapy