Potential of an age-stratified CA125 cut-off value to improve the prognostic classification of patients with endometrial cancer

Objective It is not clear whether the prognostic value of pretreatment serum CA125 levels is independent or through association with other clinicopathological features in endometrial cancer. Methods All patients with endometrial cancer treated between 2000 and 2010 were retrospectively reviewed. The correlation of clinicopathological characteristics, CA125 and treatment outcomes was analyzed. Receiver operating characteristics (ROC) curves were used to determine the CA125 cut-off values. Cox proportional hazard regression was used for multivariate analysis. Results Of the 923 eligible patients, 757 had serum CA125 levels measured before treatment. We identified 264 (34.9%) patients with pretreatment serum CA125 > 35 U/mL. By multivariate analysis, advanced stage (P = 0.001), serous or clear cell carcinoma (P = 0.008), positive peritoneal cytology (P = 0.042), and lymph node metastases (P = 0.004) were significant risk factors for cancer-specific survival (CSS), while serum CA125 > 35 U/mL (P = 0.067) was of borderline statistical significance. Using ROC curve stratified by age, we found that a serum CA125 > 35 U/mL was significant for CSS (HR = 2.34, 95% CI = 1.04-5.29) among patients > 49 years old. After adjustment for confounding factors, serum CA125 > 105 U/mL was significant (HR = 6.03, 95% CI = 1.19-30.63) in patients ≤ 49 years old. Conclusions These results suggest that an age-stratified cut-off level for CA125 (35 U/mL in patients > 49 years old and 105 U/mL in patients ≤ 49 years old) can improve the prognostic stratification of patients with endometrial cancer.