Endometriosis is associated with an increased risk of ovarian cancer, study showsBMJ 2012; 344 doi: https://doi.org/10.1136/bmj.e1363 (Published 24 February 2012) Cite this as: BMJ 2012;344:e1363
Women who have endometriosis are substantially more likely to develop three distinct histological subtypes of ovarian cancer: clear cell, endometrioid, and low grade serous, research in Lancet Oncology shows (doi:10.1016/S1470-2045(11)70404-1).
Previous studies have shown an association between endometriosis and invasive epithelial ovarian cancer (the most fatal malignancy of the female reproductive system) but have failed to characterise the relation.
Lead author Celeste Leigh Pearce, from the University of Southern California, headed a team from the Ovarian Cancer Association Consortium (OCAC) for the study which involved a pooled analysis of 13 case-control studies using data from more than 23 000 women.
The researchers concluded that endometriosis is linked to a more than threefold chance of developing clear cell ovarian cancer and doubles the risk of developing endometrioid tumours. Also for the first time a link has been shown between endometriosis and developing low grade serous ovarian cancers, doubling the risk.
The study showed no association between endometriosis and other forms of ovarian cancer.
The paper did not quote alterations or absolute risks, and doctors and patients have been advised to treat these findings with caution. Professor Hani Gabra, director of the Ovarian Cancer Action Research Centre, Imperial College London, said: “Most women with endometriosis will not go on to develop ovarian cancer.
“It is important that all women should be aware of the signs and symptoms of ovarian cancer and consult their GP if they are concerned.”
Shirley Hodgson, professor of cancer genetics at St George’s, University of London, thought the study probably showed a real finding. “The different studies all show a similar effect, and the clear discrimination between the different histological subtypes increases the probability that this is a real finding. The problem with self reported endometriosis leaves some doubt about the completeness of ascertainment of endometriosis in the cohorts, but the significance of the finding seems indisputable,” she said.
Cite this as: BMJ 2012;344:e1363