The clinical and prognostic significance of pre-chemotherapy serum CA-125 in high-risk early stage ovarian cancer: An NRG/GOG ancillary study

Objectives: To determine the clinical and prognostic significance of CA-125 trends prior to, during, and after chemotherapy in high-risk early-stage epithelial ovarian cancer patients. Methods: All patients were enrolled in a phase III randomized trial (GOG 157) following upfront surgery for grade 3 stage IA/IB, stage IC, or stage II disease, and had been treated with either three or six cycles of carboplatin/paclitaxel. Kaplan-Meier method and Cox proportional hazards model were used to evaluate recurrence-free survival (RFS) and overall survival (OS). Results: Of 350 patients, the median pre-chemotherapy CA-125 was 65 (IQR: 31–129). 71% of Whites had an elevated CA-125 compared to 47% of non-Whites (p = 0.006). Following the first cycle of chemotherapy, 74% of those with elevated CA-125 had normalization. Those who had normalization of CA-125 after 1 cycle had significantly better 5-year RFS (81% vs. 65%, p = 0.003) and OS (87% vs. 75%, p = 0.009) compared to those who did not normalize (defined as ≤35 U/mL). The pattern of CA-125 change following chemotherapy cycle 1, from normal to normal vs. elevated to normal vs. elevated to elevated had corresponding RFS of 87% vs. 80% vs. 68% (p = 0.013), and OS of 92% vs. 88% vs. 77% (p = 0.009). However, the percent decline (p = 0.993) and absolute nadir normal value of CA-125 (0–10 vs. 11–35 U/mL) were not predictive of outcome (p = 0.4). Conclusions: Normal baseline CA125 and normalization of this biomarker after the first cycle of chemotherapy were associated with better survival in high-risk early-stage epithelial ovarian cancer patients.