Women with endometriosis are nearly four times more likely to develop ovarian cancer than women without the disease, according to a new study.

Endometriosis is a common and often painful condition in which tissue similar to the lining of the uterus grows outside the uterus, affecting more than 25 million women in India.

The study, published in JAMA Network, shows that women with severe forms of endometriosis, such as deep infiltrating endometriosis or ovarian endometriomas (cysts in the ovaries), have a very high risk of ovarian cancer.

Women with these severe forms have a risk of ovarian cancer that is approximately 9.7 times greater than women who do not have endometriosis.

They are also about 19 times more likely to develop type I ovarian cancer, a slow-growing form of the disease.

However, experts advise that women suffering from endometriosis should not panic.

Ovarian cancer remains rare, and the increase in risk means there are still only 10 to 20 cases per 10,000 women.

“We wouldn’t recommend any changes in clinical care or policy at this time,” said Karen Schleip, senior author of the study and an associate professor at the University of Utah.

Preventive measures for ovarian cancer still include exercise, not smoking, and limiting alcohol. Other important risk factors include age and family history of ovarian, breast, or colorectal cancer.

Women with endometriosis should be alert to symptoms of ovarian cancer, such as bloating, abdominal pain, and changes in bowel or bladder function.

Dr. B.J. Rimel, a gynecologist at Cedars-Sinai, emphasized that oral contraceptive pills, which are often prescribed for endometriosis, can reduce the risk of ovarian cancer by 50%.

The study analyzed data from nearly 500,000 women in Utah, tracking those with endometriosis and their subsequent development of ovarian cancer.

The results showed that women with endometriosis had a 4.2 times higher overall risk of ovarian cancer.

Specifically, the risk for type I ovarian cancer was 7.5 times higher, and for the more aggressive type II ovarian cancer it was about 2.7 times higher.

The study reported a significantly higher risk for women with deeply infiltrating endometriosis or ovarian endometrioma, up to 18.8 times higher.

Dr. Michael McHale of the University of California, San Diego, who wrote an editorial on the study, emphasized the importance of counseling women with severe endometriosis about their increased risk of cancer.

He suggested that women who have conceived might consider more definitive surgical options.

This study adds to the growing evidence of the link between endometriosis and ovarian cancer, and underlines the need for informed medical advice and shared decision-making for women with endometriosis.