Prognostic value of endometriosis in patients with stage I ovarian clear cell carcinoma: Experiences at three academic institutions.

OBJECTIVES: To investigate the prognostic value of endometriosis in patients with stage I ovarian clear cell carcinoma (OCCC).

METHODS: The medical records of patients with stage I OCCC who had undergone complete staging surgery followed by systemic chemotherapy were retrospectively reviewed.

RESULTS: A total of 237 women were included in this study. Univariate analysis revealed that the patients with endometriosis-associated ovarian carcinoma (EAOC) had significantly improved recurrence-free survival (RFS) and overall survival (OS) than those without EAOC (5-year RFS: 91.4% vs. 73.0%, respectively, and 5-year OS: 97.5% vs. 89.9%). However, EAOC was not identified as a significant prognostic predictor in multivariate analysis. The potential risk factors determined to be associated with EAOC included the pretreatment CA-125 level, FIGO stage, lymphovascular space invasion (LVSI), and menopausal status (P<0.001, P=0.0031, P=0.020, and P=0.038, respectively).

CONCLUSIONS: Endometriosis was not independently associated with the prognosis of the OCCC patients, even when the tumor was confined to stage I. However, the intrinsic relationship between endometriosis and OCCC warrants further investigation.