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Ovary Removal Linked to Colon Cancer

September 01, 2016

Women who’ve had their ovaries removed may have a greater risk of colon cancer, according to a recent study’s findings.

The study, published in the British Journal of Surgery, was based on a review of 46 years’ worth of medical records of women who had undergone an oophorectomy, a procedure in which either one or both ovaries is removed. Some of the women involved in the study underwent a hysterectomy, but it wasn’t clear whether their ovaries also had been removed during this procedure. Researchers controlled for whether women in the study had diabetes, smoked, drank heavily or were diagnosed as a obese, all of which elevates a person’s risk for colon cancer.

Taking into account all these factors, researchers found that nearly 2 percent of study participants had been diagnosed with colon cancer in the following 18 years — 30 percent higher than normal for women their age. The risk also differed depending on whether only one ovary was removed. Women who removed both ovaries had a higher risk of colon cancer than those who only removed one.

Some women with a genetic predisposition to ovarian cancer have an oophorectomy to reduce their cancer risk, while others undergo the procedure to treat ovarian cysts. It’s unclear why ovary removal would increase colon cancer risk, but it could be because hormones influence the development of colon cancer and ovary removal leads to a dramatic loss of hormones like estrogen. Some studies have linked estrogen to delayed growth of colon cancer cells. 

Compared to other cancers, colon cancer isn’t usually thought to be a hormone-related disease, but research has shown that sex hormones could play a role in how this cancer develops and progresses. Research has shown that women who have been pregnant or undergone hormone therapy have increased levels of estrogen, and this is associated with a lower risk of colon cancer. In some cases, these women had a 40 percent lower risk because of their increased estrogen levels.

It’s important to understand that the study didn’t prove a direct cause-and-effect relationship between ovary removal and colon cancer, but it shows that there could be a link. We also should keep in mind the while the study controlled for several factors, it did not take into account other factors such as women’s diets or whether they had undergone hormone therapy.

So, what’s the key takeaway? Women should have a detailed conversation with their doctor about the risk of ovary removal if they are considering this procedure. If you don’t have a genetic risk for ovarian cancer or aren’t planning to undergo the procedure for serious medical reasons, it may be best to weigh all the potential risks. Talk to your doctor about what you’ve learned, so together you can make the best decision for your long-term health.