However, women who have taken hormones in the past should know that their risk drops rapidly after they stop taking them, says study author Lina Steinrud Mørch, MSc, of Rigshospitalet–Copenhagen University, in Denmark.
“Women currently taking hormones seem to reduce their risk of ovarian cancer by quitting hormone use,” Mørch says. “This risk warrants consideration when deciding whether to use hormone therapy, particularly if a woman has a special predisposition for ovarian cancer. She should consider not taking hormones.”
The overall risk is still low. The researchers estimate that hormones cause one extra case of ovarian cancer for every 8,300 women who take them each year. They say that hormone therapy caused 5%, or a total of 140 extra cases, of ovarian cancer in Denmark during the study, which ran from 1995 to 2005.
The study included 909,946 Danish women—nearly all women in the country ages 50 to 79. Overall, 3,068 developed ovarian cancer, and, of those, 2,681 were epithelial, the most common type of ovarian cancer. Current hormone users were 38% more likely to develop ovarian cancer and 44% more likely to develop epithelial ovarian cancer, in particular, than women who had never used hormones. Women who had stopped taking hormones at some point in the previous two years had a 22% higher ovarian cancer risk.
How long the current users had been taking the hormones, the combination of hormones, and the mode of delivery—oral, transvaginally, or via a patch—didn’t seem to matter.
Exactly how hormone therapy may increase cancer risk is not fully understood. “Hormone therapy causes an already latent ovarian cancer process to develop faster,” Mørch speculates.
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Comments (1)
Debbie Saslow states that bio-identical hormones that are derived from plant sources, are no more safer than estrogen from pregnant horse urin, then combined with “progestin”, a chemical that does not react the same as progesterone in the female body. That statement is not true. There are clinical studies all over the world that prove plant-based bio-identical hormones do not harm. The 2002 Woman’s Health Initiative studied the unnatural horse-urin estrogen and the chemical progestin effects in these unlucky, misinformed women untill the study was stopped because of a high percentage of the women developed breast, ovarian, etc. cancer.