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.