The significance of the change pattern of serum CA125 level for judging prognosis and diagnosing recurrences of epithelial ovarian cancer

BACKGROUND Ovarian cancer has the highest mortality rate of the three main malignant tumors of the female reproductive system, with a 5-year overall survival (OS) of only 20-30 %. Approximately 70 % of patients relapse without being cured. To explore the significance of serum CA125 level pre-treatment and the change pattern of CA125 post-treatment for judging prognosis and diagnosing recurrences of epithelial ovarian cancer (EOC). METHODS A radioimmunoassay was used to continuously monitor levels of serum CA125 in 152 patients with EOC. The first test was done before surgery, then once a month after surgery for more than two consecutive years. The data were analyzed by using Kaplan-Meier curves and the log-rank test, stratified chi-square test, Pearson correlation analysis, and multivariate Cox regression analysis. RESULTS (1) There was a relationship between patient outcomes and the serum CA125 levels before treatment and the extent and speed of serum CA125 decrease after treatment. The outcomes of patients with pre-treatment serum CA125 ≤ 35 U/ml were better than those with serum CA125 > 35 U/ml; the outcomes of patients with serum CA125 who had a logarithmic decrease or a decrease to normal within a month after treatment were also better than those with a non-logarithmic decrease or a decrease to normal that took longer than a month. (2) The results of multivariate Cox regression analysis showed that serum CA125 levels before treatment and a decreased speed of decline after treatment were independent prognostic factors; (3) The mean level of serum CA125 at relapse was 116.28 U/ml. The average time from serum CA125 increase to detection of a recurrent lesion by physical or imaging examination was 122 days. The correlation coefficient of serum CA125 level increase and tumor recurrence time was -0.674. (4) The area under the Receiver Operating Characteristic (ROC) curve of serum CA125 for diagnosing EOC recurrence was 0.879, and the sensitivity and specificity were 67.39 and 86.79 %, respectively. CONCLUSIONS It is important to monitor serum CA125 levels pre-treatment and the change pattern of CA125 post-treatment for judging prognosis and diagnosing recurrences of EOC.