Park JY, et al. - During this study, the role of ovarian endometriosis was evaluated in the prognosis of ovarian clear cell carcinoma (OCCC). Researchers found OCCC with endometriosis more frequently in younger women. Compared with OCCC without endometriosis, OCCC with endometriosis had a higher incidence of early-stage disease and a lower incidence of lymph node metastasis. Even in stage I disease, ovarian endometriosis was correlated with improved prognostic factors and a better disease-free survival (DFS) and overall survival (OS). For OCCC, ovarian endometriosis was an independent prognostic factor.

Methods

• Researchers divided patients with OCCC into 2 groups according to the presence of ovarian endometriosis:
  • Group 1- no coexisting ovarian endometriosis;
  • Group 2- clear cell carcinoma arising from ovarian endometriosis or the presence of ovarian endometriosis elsewhere in the ovary.
• They compared clinicopathologic characteristics, disease-free survival (DFS), and overall survival (OS) between the 2 groups.

Results

• Researchers categorized 77 patients into group 1 and 78 into group 2, among the 155 patients with OCCC.
• In group 2, compared to group 1, patients were found to be younger (median age, 48 vs 51 years; P=0.005) and had higher incidence of early-stage disease (stage I, 77% vs 58%; P= 0.001) and lower incidence of lymph node metastasis (4% vs 17%; P=0.008).
• Compared with group 1, group 2 patients were observed to have a significantly higher 5-year DFS (P < 0.001) and OS (P=0.001).
• Group 2 had a significantly higher 5-year DFS (P=0.004) and OS (P=0.016) than did group 1, in stage I disease.
• In the multivariate analysis, significant factors for both DFS and OS rates were coexisting endometriosis and advanced International Federation of Obstetrics and Gynecology stage.