The prognostic value of pretreatment CA-125 levels and CA-125 normalization in ovarian clear cell carcinoma: a two-academic-institute study

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.