Prognostic implication of endometriosis in clear cell carcinoma of the ovary

The aim of this study is to investigate whether the presence of endometriosis is a prognostic factor in patients diagnosed with clear cell carcinoma (CCC) of the ovary.

Retrospective chart review was performed to all patients diagnosed with CCC and endometriosis between 1975 and 2002. All pathology reports were reviewed and slides were reviewed when available. Cox regression analysis and Kaplan-Meier test were used to calculate survival prognostic factors. The level of significance was set at 0.05.

Eighty-four patients with CCC were identified with a 49% rate of coexisting endometriosis. Patients with tumors arising in endometriosis (n=15), with endometriosis found elsewhere in the specimen (n=26), and those without endometriosis (n=43) were analyzed comparatively. Patients with CCCs arising in endometriosis were 10 years younger (95% C.I. 0.6-18 years) than those with CCC not arising in endometriosis (P<0.05). Patients with endometriosis anywhere in the surgical specimen presented at early stage 66% of the times versus 42% for patients without endometriosis (P<0.05). Median overall survival (OS) for patients with endometriosis was 196 months (95% C.I. 28-363) versus 34 months (95% C.I. 13-55) for patients without endometriosis (P=0.01). Advanced tumor stage at diagnosis (HR 13, 95% C.I. 5-29, P=0.001) and absence of endometriosis (HR 2, 95% C.I. 1-3.9, P=0.03) were the only significant prognostic factors associated with poor survival. Disease recurrence or death among optimally and completely cytoreduced patients was 31% and 59% for those with and without endometriosis respectively (P>0.05).

Our study suggests that the presence of endometriosis in patients with CCC of the ovary is associated with progression free and OS advantages with no difference in initial resectability.