In a collaborative research effort in Europe, investigators looked at whether a cause-and-effect relationship existed between a rare cancer known as ovarian clear cell carcinoma (OCCC) and endometriosis. In the population evaluated, no concrete link was observed.
The study, led by researchers with the Clinic of Operative and Oncologic Gynecology at the Medical University of Lodz, Poland, was titled “Clear cell ovarian cancer and endometriosis: is there a relationship?” and published in the July edition of the journal Menopause Review.
OCCC is a subtype of ovarian cancer associated with the epithelial (top-most) layer of the ovaries’ tissue. This rare cancer makes up less than 5% of ovarian cancers diagnosed (2006 estimate), and it has been linked to unfavorable prognosis in diagnosed patients.
Research literature that focused on the pathophysiology — the functional changes — of endometriosis has suggested that there may be a potential genetic link between endometriosis and OCCC. Researchers decided to investigate that potential link further in clinical patients.
Here, the researchers analyzed the histopthological data, or data from the microscopic examination of specific body tissues to understand the effect of the disease, in 394 patients operated on for ovarian cancer at the Polish clinic. The scientists also looked at the patients’ menstrual history, pregnancy history (parity), and comorbidities, as well as data from physical examinations, operational protocols and histopathological diagnoses.
The main finding of interest in relation to a potential cause-and-effect relationship was that the investigators could not prove, either clinically or histologically, a coexistence of endometriosis in these patients. This means that, for this study population, the findings did not show a link between endometriosis and OCCC. Hypertension was found to be the most common comorbidity in the study group.
In essence, this is a great example of a negative study. The publishing of negative study data is an important part of the scientific method, as it adds to the body of knowledge that researchers pull from when designing studies to ask scientific questions.
“Establishing the cause-and-effect relationship between this histopathological subtype and endometriosis cannot be proved based on clinical material of only one clinic or operative ward,” the researchers concluded, suggesting that future “statistical studies of available publications targeted at comparing the clinical and molecular groups of patients with endometriosis and OCCC” be performed.