According to a recent article published in The Journal of the American Medical Association, additional data indicate that the use of continuous combined estrogen and progestin (a synthetic form of progesterone) hormone therapy increases the risk of breast cancer in postmenopausal women.
Hormone replacement therapy (HRT) is often prescribed for women during menopause. Menopause is a natural phase of maturing womanhood, during which the ovaries produce significantly less estrogen, ovulation ceases and menstruation ends. For many women, menopause has uncomfortable side effects. Hot flashes, sleep disturbances, depression, mood swings and anxiety may affect the menopausal woman. Additionally, menopause may also be accompanied by increased urinary tract infections, incontinence, vaginal discomfort due to a lack of estrogen-based lubrication and decreased bone density. HRT has been effectively used to mitigate these side effects and is widely prescribed for women experiencing these unpleasant symptoms of menopause. Recent results from several clinical studies have demonstrated a correlation between the use of hormone therapy and the development of breast cancer. However, it is not yet clear which particular types and regimens of hormone therapy are associated with the greatest risks of developing breast cancer.
Researchers have recently collected updated data from the womens health initiative (WHI) clinical trial which was developed to determine effects of HRT in postmenopausal women. This trial involved women between the ages of 50 and 79 years who were given daily HRT composed of both estrogen and progestin, or placebo (inactive substitute). The trial was stopped early (5.2 years) after results indicated that severe side effects were associated with the group of women receiving HRT, including a 24% increased risk of developing breast cancer as well as increased rates of stroke and heart attacks, compared to the group of women receiving placebo. In addition, breast cancer tended to be diagnosed at a later stage (extent) in women receiving HRT, compared to women receiving placebo.
These updated results add to a growing number of papers that indicate an association may exist between HRT containing both estrogen and progestin are at an increased risk in the development of breast cancer in postmenopausal women. However, it is important for patients to discuss the risks and benefits of HRT in their particular situation with their physician.
Reference: Cheblowski R, Hendrix S, Langer R, et al. Influence of estrogen plus progestin on breast cancer and mammography in healthy postmenopausal women. The Journal of the American Medical Association. 2003;289:3243-3253.