Cancers in Patients with Endometriosis

Background:

It is known that endometriosis is associated with an increased risk for certain forms of ovarian cancer. However it is unknown, which kind of endometriosis is associated with ovarian cancer and furthermore, if endometriosis is associated with the risk for other cancers than ovarian cancer. However similar to other diseases endometriosis is a heterogeneous disease having different effects on pain or fertility as well as endometriosis is located in several locations like peritoneum, ovaries, uterus and might even infiltrate adjacent organs. Aim of this study was to describe the freuqencies of cancers as co-morbidities in a population of endometriosis patients.

Material and Methods:

Within the International Endometriosis Evaluation Program (IEEP) a total of over 9523 patients have been documented beween February 2014 and July 2018. For this retrospective analysis patients had to be excluded without a documented surgical diagnosis of endometriosis. Further 560 patietns wer excluded without exact documentation of the location of the endometriosis lesion. No documentation of co-morbidities was done in 1697 patients resulting in the exclusion of those patients. Therefore the final study population consisted of 4539 endometriosis patients. Cancer diagnosis frequencies were calculated for the following 5 groups. Group 1: peritoneal endometriosis, group 2: peritoneal endometriosis and adenomyosis, group 3: adenomyosis only, group 4: peritoneal endometriosis and deep infiltrating endometriosis, group 5: ovarian endometriosis.

Results:

With regard to the 4539 pateints, in 107 cases (2.4%) a malignant disease was documented. In patietns from group 2 the cancer prevalence was highest with 3.2% and 0.9% in the group of patients with deep infiltrating endometriosis. Interestingly of 5 endometrial cancers 4 were diagnosed in patients with adenomyosis and 2 of 3 ovarian cancers in the group of patients with ovarian endometriosis.

Conclusion:

This study is one of the first to analyze cancer prevalence in a group of endometriosis patients. There is some evidence, that cancer might be more prevalent in the group of patients with peritoneal endometriosis paired with adenomyosis. However sample sizes of patients diseased with cancer is small. Therefore larger registries are needed to adress this question further.