Women with endometriosis face fourfold higher risk of ovarian cancer, study finds

The risk of developing ovarian cancer could jump about fourfold among women with endometriosis compared with women without the condition, a new study has found.

A landmark study from researchers at the University of Utah and Boston University Chobanian & Avedisian School of Medicine found that women with severe endometriosis are 10 times more likely to get ovarian cancer compared to women who do not have the disease.

Prior studies have shown a causal connection between endometriosis and ovarian cancer but in using the Utah Population Database, a repository of linked health records housed at Huntsman Cancer Institute at the University of Utah, investigators were able to analyse the incidence rates of different types of endometriosis and subtypes of ovarian cancer for the first time.

Their research, which included a cohort of over 78,000 women with endometriosis, found that women with severe forms — either deep infiltrating endometriosis, ovarian endometriomas or both — have an overall ovarian cancer risk that’s “markedly increased,” at about 9.7 times higher, relative to women without endometriosis.

Women with deep infiltrating endometriosis, ovarian endometriomas or both, on the other hand, appear to face nearly 19 times the risk of type I ovarian cancer, which tends to grow more slowly, compared with women without endometriosis, according to the study.

In their calculations, researchers also found that women with any kind of endometriosis have a 4.2-fold risk of developing ovarian cancer compared to those who do not.

“These are really important findings,” said Jennifer Doherty, investigator and professor of the population health sciences department at the University of Utah.

“This impacts clinical care for individuals with severe endometriosis, since they would benefit from counselling about ovarian cancer risk and prevention.

“This research will also lead to further studies to understand the mechanisms through which specific types of endometriosis cause different types of ovarian cancer.”

However, women with endometriosis should not panic about the findings, researchers noted, because ovarian cancer itself is still rare. About 1.1 per cent of US women will be diagnosed with ovarian cancer at some point in their lifetime, according to the National Cancer Institute.

“Because of the rarity of ovarian cancer, the association with endometriosis only increased the number of cancer cases by 10 to 20 per 10,000 women,” Karen Schliep, senior author of the study and an associate professor in the Division of Public Health at the University of Utah School of Medicine, told CNN.

“We would not recommend, at this point, any change in clinical care or policy. The best way of preventing ovarian cancer is still the recommendation of exercise, not smoking and limiting alcohol.”

Women with endometriosis could pursue surgeries, such as hysterectomies or removal of the ovaries, investigators said. However, since these are invasive procedures, more research is needed to know if these are the right measures, they concluded.