Objectives The association between endometriosis and ovarian carcinoma has been widely proposed. We retrospectively evaluated clinical manifestation, surgical outcome and complication of endometriosis-associated ovarian cancer compare to non-endometriosis-associated ovarian cancer with histologic type of clear cell carcinoma and endometrioid carcinoma.

Methods The study was conducted to review 330 patients with primary ovarian clear cell carcinoma and endometrioid carcinoma who had been initially treated at Rajavithi Hospital. The clinical backgrounds, surgical outcome and complication was reviewed.

Results 13.51% had pathological-confirmed coexisting endometriosis in clear cell carcinoma and endometrioid carcinoma. 76.57% of endometriosis-associated ovarian cancer (EAOC) presented with earlier stage (stage I-II) than non-EAOC. The higher probability of optimally surgical staging was reported in EAOC compare to non-EAOC with statistically significance (77.8% versus 54.7% respectively, p=0.002). Post-operative complication was also lower in EAOC (p=0.02). There was no difference on age, stage and surgical outcome between clear cell carcinoma and endometrioid carcinoma associated with endometriosis.

Conclusions Endometriosis-associated ovarian cancer related to early-stage disease and tend to underwent optimal surgery. The operative complication seemed to be lower in endometriosis-associated ovarian cancer.