Data from a pooled analysis has linked endometriosis with an increased risk for being diagnosed with low-grade serous, endometrioid or clear-cell ovarian cancers.
Previously performed epidemiological studies have had conflicting results as to whether there may be an association between endometriosis and epithelial ovarian cancer.
In this study, researchers sought to examine if there was any association between endometriosis and the five subtypes of epithelial ovarian cancer: clear-cell, endometrioid, mucinous, high-grade serous and low-grade serous.
To do that, the researchers conducted a pooled analysis of 13 case-control studies in the Ovarian Cancer Association Consortium. Nine studies were conducted in the United States, one was conducted in Australia and three took place in Europe. The studies included 13,226 control patients and 7,911 women with invasive ovarian cancer.
Of the women whose data was included in the analysis, 818 controls and 738 women with ovarian cancer reported a history of endometriosis. Although no association was reported between endometriosis and mucinous or high-grade serous invasive ovarian cancer, associations were reported for the other three subtypes.
Specifically, there was significantly increased risk for clear-cell cancer (OR=3.05; 95% CI, 2.43-3.84), low-grade serous cancer (OR=2.11; 95% CI, 1.39-3.20) and endometrioid cancers (OR=2.04; 95% CI, 1.67-2.48).
In addition, researchers found no association between endometriosis and borderline tumors of either serous or mucinous subtypes.
“Future research should focus on identification of factors that are associated with malignant transformation of endometriosis and subsequent risk of low-grade serous, clear-cell, and endometrioid ovarian cancers to identify women for whom more definitive endometriosis treatment and ovarian cancer surveillance would be appropriate,” the researchers wrote.