A recent study concludes that women with endometriosis are at increased risk of developing ovarian cancer. Risks of developing three specific types of ovarian cancer were found to be more than double for women with endometriosis.
Endometriosis is a condition where the type of tissue that normally lines the uterus (womb) also grows outside of it. This misplaced tissue thickens, breaks down and bleeds during the menstrual cycle, but cannot exit the body like normal uterine tissue does. This can cause a variety of painful conditions and may also lead to infertility. More than five million women in the U.S. suffer from endometriosis.
Because clear-cell cancers can often be detected at an early stage when they are most treatable, women with endometriosis might want to discuss routine screening with their doctor.
A few previous small-scale studies have suggested a link between endometriosis and ovarian cancer, but this association was not considered definitive until now.
The current study analyzed 13 previous studies that were part of the Ovarian Cancer Association Consortium, a project that looked for genetic associations with ovarian cancer. Though not designed as studies of endometriosis, the women in these studies did report if they had endometriosis. The researchers from the current study used this information along with cancer diagnosis rates to determine how endometriosis affected the risk of developing five different types of ovarian cancer.
The 13 studies included over 23,000 participants, nearly 8,000 of whom had been diagnosed with ovarian cancer.
The analysis found that the risk for two types of ovarian cancer, low-grade serous and endometrioid ovarian cancer, were more than double in women with self-reported endometriosis. The risk of a third type of ovarian cancer, clear-cell cancer, was more than triple.
There was no increased risk seen of two other types of ovarian cancer, mucinous or high-grade serous cancers.
An article on the study was published online by The Lancet Oncology.