As women reach menopause and beyond, more than 80% will experience symptoms such as hot flashes, night sweats, sleep disturbance, and vaginal dryness. Hormone therapy-typically comprised of estrogen, with or without progestin-is a common and effective treatment for many of these symptoms. Recent studies, however, have raised concerns about the health effects of postmenopausal hormone therapy.
Use of estrogen plus progestin has been linked with an increased risk of heart disease, breast cancer, stroke, and blood clots and a decreased risk of fractures and colorectal cancer. Use of estrogen alone, which is generally reserved for women who have had a hysterectomy, has been linked with an increased risk of strokes and a decreased risk of fractures. More recently, research has indicated a potential increase in the risk of ovarian cancer among women who use hormone therapy; however, because studies have been limited, this association remains unclear. Researchers continue to evaluate the potential risks and benefits of hormone therapy in postmenopausal women.
Researchers from Boston, Massachusetts, recently conducted a clinical study to further evaluate the effects of hormone therapy on postemenopausal women. This study included nearly 83,000 postmenopausal women who were involved in the Nurses’ Health Study from 1976 to 2002. Overall, there were 389 cases of ovarian cancer.
- Women who were current users of hormone therapy and those who were past users of hormone therapy for five years or longer had a significantly increased risk of ovarian cancer.
- Estrogen alone (unopposed estrogen) was associated with a significant increase in several different types of ovarian cancer, including epithelial ovarian cancer, which is the most common type of ovarian cancer. However, estrogen plus progestin was not associated with a significant increase in the risk of ovarian cancer overall.
- It appears that the duration of time since use of hormone therapy did not affect the risk of ovarian cancer.
The researchers concluded that it appears that use of unopposed estrogen significantly increases the risk of developing ovarian cancer among postmenopausal women. Women who were either current users or had in the past used hormone therapy continuously for at least five years were both susceptible to this increased risk.
Postmenopausal women who are or were using unopposed estrogen may wish to speak with their physician regarding their individual risks of developing ovarian cancer as well as possible screening for the disease. Further research regarding the association between hormone therapy and ovarian cancer risk will increase understanding of this issue.
 Rossouw JE, Anderson GL, Prentice RL et al. Risks and benefits of estrogen plus progestin in healthy postmenopausal women: principal results from the Women’s Health Initiative randomized controlled trial. JAMA. 2002; 288:321-33.
 Anderson GL, Limacher M, Assaf AR et al. Effects of conjugated equine estrogen in postmenopausal women with hysterectomy: the Women’s Health Initiative randomized controlled trial. JAMA. 2004; 291:1701-1712.