The surgical, histopathological characteristics, and survival outcome of ovarian clear cell carcinoma: a retrospective case series sharing the experience of a tertiary cancer centre.

BACKGROUND: Ovarian clear cell carcinoma (OCCC) is a rare and distinct subtype of epithelial ovarian cancer (EOC). It is unique in several biological aspects. This study analyzes the clinicopathological features and survival outcome of patients with OCCC, aiming to identify factors affecting recurrence, progression-free survival (PFS) and overall survival (OS). METHODS: A retrospective study included 49 women with OCCC between January 2009 and December 2021 at Oxford Cancer Center. All demographic and pathological characteristics, pre-operative biomarkers, surgical procedure, complications, hospital stay, chemotherapy regimen, and disease status on follow-up, were collected from electronic medical records. RESULTS: No residual disease (R0) was achieved in 39 out of 49 women who underwent cytoreductive surgery. The follow-up time had a mean of 8.75 years. The 3-year OS was 73.4%, and the 3-year PFS was 81.3% [95% confidence interval (CI): 84.63-118.93]. Women with stage 1 disease had the best outcome. There was a marked difference (P<0.001) in OS in the presence of residual disease. No residual disease conferred a 3-year OS of 88.6% (95% CI: 108.6-141.8), compared to only 12.5% in the presence of residual disease (95% CI: 4.48-32.11). In multivariant analysis, the International Federation of Gynecology and Obstetrics (FIGO) stage was the only independent prognostic indicator of OS with (P<0.05), including carbohydrate antigen (CA) 125, hemoglobin, albumin, associated endometriosis, ascites, residual disease and FIGO staging. CONCLUSIONS: Surgery to achieve no residual disease is necessary to improve the prognosis in advanced OCCC. The true challenge is to predict which patients with early-stage disease at higher risk of recurrence and would most benefit from adjuvant treatments.