Objectives: The present study investigated the clinical implications of pretreatment carbohydrate antigen 125 (CA-125) levels and CA-125 normalization in patients with ovarian clear cell carcinoma (CCC), and it provides useful information for the improvement of monitoring strategies for this lethal disease.
Methods: The medical records of patients with ovarian CCC who had undergone primary staging surgery or cytoreductive surgery followed by systemic chemotherapy were retrospectively reviewed. A range of clinico-pathological parameters were collected and examined.
Results: A total of 375 women were included in the analysis. FIGO stage (p < 0.001) was identified as the only significant prognostic factor for relapse. Residual tumor and advanced stage (p = 0.001 and p < 0.001, respectively) were identified as independent adverse factors for survival. The potential risk factors associated with elevated pretreatment CA-125 levels included advanced-stage disease, positive residual tumors and negative endometriosis (p < 0.001, p = 0.001 and p <0.001, respectively). Pretreatment CA-125 levels were not associated with relapse-free survival (RFS) or overall survival (OS) (p = 0.060 and p = 0.176, respectively). CA-125 normalization after chemotherapy exhibited a positive linear correlation with advanced stage (r = 0.97, p = 0.001) and residual tumor (r = 0.81, p = 0.027) and a negative relationship with 5-year RFS (r = -0.97, p = 0.002) and 5-year OS (r = -0.97, p= 0.001). Patients with CA-125 levels that normalized before cycle 2 of chemotherapy had a similar prognosis as patients whose CA-125 levels normalized prior to chemotherapy (RFS: p = 0.327; OS: p = 0.654). By contrast, patients with CA-125 levels that normalized after cycle 2 of chemotherapy or never normalized were significantly more likely to experience disease progression.
Conclusions: Pretreatment CA-125 levels are not very useful for predicting clinical outcome. CA-125 levels following treatment are a valid indicator for treatment monitoring. CA-125 normalization after the completion of cycle 1 of chemotherapy represents a distinct inflection point for decreased RFS and OS.
Keywords: CA-125; clear cell carcinoma; normalization; ovary; pretreatment.