Endometriosis may be linked to ovarian cancer – but it’s not all bad news

Endometriosis is a chronic, debilitating disease that affects the health of one in women of reproductive age, in which tissue similar to the uterus lining grows in other parts of the body, such as the bladder or bowel.

It’s thought to be the cause of up to half of all unexplained infertility, and in some cases can cause pain so severe that sufferers are entirely incapacitated.

Worryingly, a number of studies have suggested that endometriosis sufferers may also carry a greater risk of developing ovarian cancer – but a causal link between the two reproductive disorders has remained elusive.

Now, publishing their findings in Cell Reports Medicine, researchers from the University of Queensland have demonstrated a genetic link between endometriosis and some types of ovarian cancer.

“More information about how they develop, their associated risk factors, and the pathways shared between endometriosis and different types of ovarian cancer has been needed,” says study author Dr Sally Mortlock, of the UQ Institute for Molecular Bioscience, drawing attention to the lack of research attention that has long plagued this area of women’s health.

“Our research shows that individuals carrying certain genetic markers that predispose them to having endometriosis also have a higher risk of certain epithelial ovarian cancer subtypes, namely clear cell and endometrioid ovarian cancer.”

The study combined large datasets, comparing the genomes of 15,000 people with endometriosis and 25,000 with ovarian cancer to find an overlap in risk factors between the two diseases.

While their results demonstrate a clear and significant biological overlap between the disorders, the researchers say it’s not an immediate cause for alarm for endometriosis sufferers.

“Overall, studies have estimated that 1 in 76 women are at risk of developing ovarian cancer in their lifetime, and having endometriosis increases this slightly to 1 in 55, so the overall risk is still very low,” she said.

Rather than raising red flags, the link instead may lead to positive developments in treatments for both disorders. By exploring specific areas of DNA that increase the risk of both diseases, the researchers were able to identify genes in both ovarian and uterine tissue that could be targets for future drug therapies.  

Something of a silent epidemic, endometriosis affects an estimated 176 million women worldwide – a number comparable to diabetes – but has traditionally received little research attention. Sufferers often struggle through years, or even decades, of pain before receiving a diagnosis, and the success of treatment options is highly variable.

The treatment possibilities opened up by studies such as this one, that begin to uncover the genetic underpinnings of gynaecological disorders, offer hope that we may have turned a corner towards addressing this enormous health issue with the attention it deserves.