A study of Swedish women suggests that some forms of hormone replacement therapy (HRT) are associated with a modest increase in risk of epithelial ovarian cancer. The findings appear in the April 3 issue of the Journal of the National Cancer Institute.
Tomas Riman, M.D., of Falu Hospital and Karolinska Institute in Sweden, and his coworkers report that the use of both estrogens and estrogens combined with a sequential, or cyclic, regimen of progestins was associated with an increased risk of epithelial ovarian cancer. However, use of estrogens combined with a continuous, or daily, regimen of progestin was not associated with increased ovarian cancer risk.
Estrogen replacement therapy, which helps relieve symptoms of menopause and may prevent osteoporosis and heart disease, has been associated with an increased risk of uterine cancer. In women with an intact uterus, combining estrogens with progestins has been shown to reduce this risk.
Results of epidemiologic studies looking at estrogen replacement therapy and the risk of ovarian cancer have not been as clear. The authors point out that most studies that examined hormone replacement therapy and ovarian cancer did so without indicating whether estrogens were taken alone or supplemented with progestins.
In the new study, Riman and his coworkers identified 655 women with epithelial ovarian cancer from Swedish cancer registries, along with 3,899 cancer-free women. The women, who were between the ages of 50 and 74, completed questionnaires about their history of HRT use and other factors that may have affected their risk of ovarian cancer.
The authors found that women who had used estrogens alone had a 43% increased risk of developing epithelial ovarian cancer compared with women who had never used such therapy. However, this risk increase was seen only in women with an intact uterus. Women who had undergone hysterectomies and had used estrogens were not at increased risk of ovarian cancer.
Moreover, women who had used estrogens combined with sequential progestins had a 54% increased risk of developing epithelial ovarian cancer compared with women who had never used this type of therapy. Women who had used estrogens combined with continuous progestins did not appear to have an increased risk of ovarian cancer.
While the greatest risk increases were seen in women who had used either form of HRT for more than 10 years, the authors caution that the increase in risk is modest. They note that, of 1,000 women taking estrogens alone or with sequential progestins, only two or three will develop ovarian cancer as a result. In Sweden, one out of 100 women between the ages of 50 and 75 will develop ovarian cancer regardless of HRT use.
Consequently, the authors do not recommend changing current prescribing practices: “For women to make an informed decision about whether or not to use HRT, all beneficial and adverse hormonal aspects concerning [breast cancer,] osteoporosis, coronary heart disease, venous thrombosis, and other health effects must be addressed.”
However, they write, “if our findings are replicated it would be valuable to consider the epithelial ovarian cancer risk increase associated with the use of certain HRT regimens, especially given the prevalence of HRT use and the poor prognosis of epithelial ovarian cancer.”
Contact: Tomas Riman, M.D., Falu Hospital, 46 23 490565; fax: 46 23 490989, email@example.com (On April 3 from 7 a.m. to 4 p.m. GMT: Department of Medical Epidemiology, Karolinska Institute, 46 8 7286160; fax: 46 8 314957)
Riman T, Dickman PW, Nilsson S, Correia N, Nordlinder H, Magnusson, CM, et al. Hormone-replacement therapy and the risk of invasive epithelial ovarian cancer in Swedish women. J Natl Cancer Inst 2002;94:497–504.
Source: Journal of the National Cancer Institute