" A new study shows women who undergo surgical treatment for endometriosis have a lower risk of developing ovarian cancer. The Swedish research also found that hormonal treatments for endometriosis did not lower the risk." http://www.m.webmd.boots.com/a-to-z-guides/news/20130411/endometriosis-surgery-ovarian-cancer
" There is sufficient evidence to conclude that there is an increased risk of developing clear-cell and endometrioid epithelial ovarian cancer for women with histologically verified endometriosis. Nonetheless, prospective cohort studies assessing the relation between endometriosis and ovarian cancer will increase knowledge in this field." http://www.ncbi.nlm.nih.gov/m/pubmed/24011403/
From 2014:
" Genetic studies have demonstrated that endometriotic lesions have mutations in genes directly related to neoplasms, in particular the p53, KRAS, PTEN, and ARID1Agenes, which suggests a direct transition from a subset of endometriotic lesions to invasive carcinomas. The identification of both genetic and epigenetic biomarkers including microRNAs are essential for identifying patients at risk for the transition to neoplasia." http://www.sciencedirect.com/science/article/pii/S1553465013004305
From 2012:
"According to the article published today, women with endometriosis have an odds ratio of about 1.5 of developing an invasive ovarian cancer compared to the general female population.
“From this point of view, these data are “reassuring” in comparison with some previous reports indicating a much higher risk. An odds ratio of 1.5 means that a woman with endometriosis has a life-time risk of developing an ovarian cancer of about 1.5% instead of 1%”
WES President, Paolo Vercellini
said World Endometriosis President, Professor Paolo Vercellini.
Whereas the study showed no link between endometriosis and high-grade serous, mucinous, serous borderline, or mucinous borderline ovarian cancers, the authors stress that their paper describes for the first time an association between endometriosis and low-grade serous ovarian cancers translating to a doubling of the risk in women with a history of endometriosis.
Professor Vercellini agrees this is an important finding, but does offer another word of caution:
This finding only has pathogenic and not clinical implications, as the incidence of this cancer subtype is limited to 336 out of 7911 cases in this pooled analysis and thus the practical consequences are modest.
Indeed he stresses that it is important to be cautious with the definition of endometriosis in general as a precursor lesion for clear-cell and endometrioid ovarian cancers, as reasonably only atypical endometriosis should be considered a definite precursor lesion [2].
Furthermore, without the specification of which sub-types of endometriosis, the lack of information on subsequent treatment with or without danazol, and the possible differential recalling rate between cases and controls, there are still some uncertainties that need to be resolved in future studies.
In particular, future studies need to determine whether the association is causal with a clear temporal relationship or merely association due to exposure to shared risk factors." http://endometriosis.ca/news/article/ovarian-cancer-risk-in-women-with-endometriosis/