Purpose: This study aimed to compare the clinical characteristics and outcomes of the cases with pure ovarian clear cell adenocarcinoma (OCCC), mixed type (clear plus serous or clear plus endometrioid or serous plus clear plus endometrioid) ovarian adenocarcinoma (MOC) and high-grade serous ovarian adenocarcinoma (HGSOC).
Methods: A retrospective comparison was conducted in 32 cases with pure OCCC, 23 cases with MOC and 28 cases with HGSOC followed between January 1999 and October 2011. Clinico-pathologic characteristics including histopathologic subtypes, age, stage, presence of ascites and/or peritoneal carcinomatosis, endometriosis and optimal cytoreduction, and also survival rates were compared in these three groups.
Results: The cases with pure OCCC were younger than the cases with MOC and HGSOC (p = 0.004). The median pre-operative CA-125 level was lower in the pure OCCC than in MOC and HGSOC (p = 0.006) (p = 0.001, p = <0.001, respectively). Bilaterality and peritoneal carcinomatosis were more frequently seen in the HGSOC group (p = 0.001, p < 0.001, respectively). The majority of the cases (65 %) had stage I or II disease in the pure OCCC group, but most of the cases in the HGSOC group had advanced stage disease (p < 0.001). Endometriosis was found in 16 cases (16/55, 29 %) in the OCCC group. No significant difference was detected with regard to the median survival rate among three groups (p = 0.517), while the stage of disease was found to be the only important factor for survival (p = 0.002).
Conclusion: Pure OCCC, MOC and HGSOC represent distinct clinical characteristics. Clinical characteristics of MOC are more similar to those of HGSOC.