Comparison of clinical outcomes of patients with clear cell and endometrioid ovarian cancer associated with endometriosis to papillary serous carcinoma of the ovary

Objective The aim of this investigation was to compare outcomes of patients with clear cell carcinoma (CCC) and endometrioid carcinoma (EC) of the ovary associated with endometriosis to patients with ovarian papillary serous carcinoma (PSC). Methods Patients with CCC and EC of the ovary associated with endometriosis were identified and matched by age and stage to PSC controls. Student's t test and chi square test were used to analyze continuous and categorical data. The Kaplan-Meier method was used for survival analysis. Results 67 cases associated with endometriosis were identified, of which 45 were arising in endometriosis. Cases were matched to 134 PSC controls. 27 patients with tumors associated with endometriosis presented at stage I (40.3%), 27 at stage II (40.3%), ten at stage III (14.9%) and three at stage IV (4.5%). There was no difference in rate of optimal cytoreduction or response to chemotherapy in cases vs. PSC controls. There was a significant increase in synchronous endometrial cancer in tumors associated with endometriosis compared to PSC (25.4% vs. 3.7%; P < 0.001). 18 cases (26.9%) had recurrent disease vs. 55 (41%) controls (P = 0.03). The 5-year disease-free survival (DFS) and overall survival (OS) of patients with tumors associated with endometriosis compared to PSC controls were 75% vs. 55% (P = 0.03) and 85% vs. 77% (P = 0.2), respectively. Conclusions Patients with tumors associated with endometriosis had a higher rate of synchronous endometrial cancer. Cases also demonstrated a lower rate of recurrence and improved 5 year DFS; however, this did not translate into a difference in OS.