Ovarian cancer risk linked to hormone therapy
Women who take hormone replacement therapy after menopause are at increased risk of ovarian cancer, according to a new study published in the Journal of the American Medical Association.
Compared with women who have never taken hormone replacement therapy, those who currently take it or those who have used it in the past are at increased risk of developing ovarian cancer. This risk does not appear to be affected by how long a woman had used hormone therapy, the type of formulation she used, or the estrogen dose.
According to the American Cancer Society, the estimated number of ovarian cancer cases and deaths in the United States for 2009 are 21,550 and 14,600, respectively. Ovarian cancer is the fifth cause of cancer death in women and the ninth most common cancer in women. Approximately two-thirds of women who have ovarian cancer are 55 years or older.
The researchers collected data from Danish national registers (years 1995 through 2005) concerning 909,946 women aged 50 through 79 years. The study population included women who both were and were not using hormone replacement therapy. None of the women had hormone-sensitive cancers when they entered the study.
Over an average of eight years of follow-up, the researchers found 3,068 cases of ovarian cancer. Compared with women who had never used hormone replacement therapy, those who were currently using hormones had an increased risk of developing ovarian cancer that approximated one extra ovarian cancer for about every 8,300 women using hormone therapy.
Overall, a woman’s risk of developing invasive ovarian cancer during her lifetime is about 1 in 71. Women’s lifetime chance of dying from invasive ovarian cancer is about 1 in 95. Women who are using hormone replacement therapy or who are considering such therapy should discuss the risks with their physician.
Sources: Morch LS et al. Hormone therapy and ovarian cancer. JAMA 2009 Jul 15; 302(3): 298-305.
American Cancer Society