I’ve received questions from women who are taking hormone therapy for menopausal symptoms who are wondering about a flurry of news reports this last week like this one from Bloomberg News: “Women who had hormone therapy for menopause symptoms were more likely to develop ovarian cancer, regardless of the length, formulation, or type of treatment they received.” If you or someone you love is on hormone therapy, should you worry?
Furthermore this report claims, “if a woman has a special predisposition for ovarian cancer, she should consider not taking hormones.”
Before I answer whether you should worry or not, I need to share a brief teaching point. When reading news headlines about the risk of this or that, you need to be aware of “relative risk” and “absolute risk.”
Let me show you how this works. In the case of this particular study, the “absolute risk” of a menopausal woman who is taking hormone therapy in being diagnosed with ovarian cancer is very, very small.
In fact, they calculated that for every 8,300 women taking hormone therapy, there would be only one extra case of ovarian cancer per year. That’s one case in 8,300 women. That’s an “absolute risk” of less than 0.012% per year.
Now, when it comes to the much scarier number of “relative risk,” you need to know that the researchers examined data on 909,946 Danish women, between the ages of 50 to 79, and found there were, overall, 3,068 cases of ovarian cancer during eight years of follow-up.
The researchers reported that current users of hormone therapy had a 38% increased risk of ovarian cancer and a 44% increased risk of epithelial ovarian cancer. Here they are talking about “relative risk.”
And it’s “relative risk” that is usually reported in the media. Why? The numbers are much scarier.
The researchers, wisely, reported the absolute and relative risks. About the absolute risk they write, “The incidence rates in current and never users of hormones were 0.52 and 0.40 per 1000 years, respectively.” In other words, about 2,000 women would have to take hormone therapy for a year for one of them to have a statistical chance of developing a hormone therapy related ovarian cancer.
So, for any one woman, the risk is very, very small. Nevertheless, I recommend that each woman discuss all of the risks, benefits, and costs of hormone therapy with her personal physician. And, as I’ve mentioned in previous blogs, all of the national recommendations for hormone therapy for menopausal symptoms recommend the lowest dose of hormone therapy for as short a time as possible.
So, when you read medical news stories discussing risk, remember that the “relative risk” is the one you usually see in the headlines. But always, always, look in the fine print.