Endometriosis Increases Risks of Ovarian Cancer

Ovarian cancer subtypes associated with endometriosis

(RxWiki News) Millions of women and girls in the United States and around the world suffer from the painful, chronic condition known as endometriosis. Recent research indicates this condition could be a risk factor for ovarian cancer.

An international study has concluded that women who have had a history of endometriosis are at far greater risk of developing three types of ovarian cancer than women who don't have the condition.

The three types of ovarian cancer are clear cell, endometrioid, and low-grade serous.

"Talk to your gynecologist about your history of endometriosis."

Earlier, smaller studies have hinted at a link between endometriosis and epithelial ovarian cancer, the most common and lethal form of the disease. This new research adds weight to these findings and adds new associations.

Endometriosis is a common disorder that affects roughly 10 percent of women who are in their reproductive years.

"This breakthrough could lead to better identification of women at increased risk of ovarian cancer and could provide a basis for increased cancer surveillance of the relevant population, allowing better individualization of prevention and early detection approaches such as risk-reduction surgery and screening", explains lead study author, Celeste Leigh Pearce from the University of Southern California, Los Angeles, lead author of the study.

This research was based on analyzing results from 13 studies, which included information from more than 23 000 women: 13,326 healthy women, 7,911 women with invasive ovarian cancer and 1,907 women with borderline cancer.

A team of researchers from The Ovarian Cancer Association Consortium (OCAC) calculated the size of the association between endometriosis and the risk of each of the five major types of ovarian cancer - high-grade serous, low-grade serous, clear cell, endometrioid, and mucinous carcinomas.

They found that endometriosis is associated with:

  • A more than threefold chance of developing clear-cell ovarian cancers
  • A more than double the risk of developing endometrioid tumors
  • Double the risk of low-grade serous ovarian cancers
  • No increased risk of high-grade serous, mucinous, serous borderline, or mucinous borderline ovarian cancers
  • The authors caution that while they have established strong links, "most women with endometriosis do not develop ovarian cancer."

They add, "However, healthcare providers should be alert to the increased risk of specific subtypes of ovarian cancer in women with a history of endometriosis."

The study was published February 21, 2012 Online First in the Lancet Oncology.

This work was supported with donations by the family and friends of Kathryn Sladek Smith to the Ovarian Cancer Research Fund. It was also supported by the National Institutes of Health; California Cancer Research Program California Department of Health Services and a number of other research organizations in the UK, Germany, Australia and Denmark.

The authors declared no conflicts of interest.