OBJECTIVE: This prospective study was conducted to determine the correlation between preoperative serum CA 125 levels and the presence of surgicopathologic prognostic factors in endometrial cancer. Subsequently, the study also aimed to determine the CA 125 cutoff value which best predicted the prognostic factors to which it had a significant correlation.
METHODS: Patients diagnosed with endometrial cancer at a tertiary gynecologic oncology unit from October 2006 until July 2008 who were eligible for primary surgical treatment were included in this analysis. Blood was extracted for serum CA 125 determination using a chemiluminescent enzyme immunoassay (CLEIA) prior to surgery. All patients underwent exploratory laparotomy, peritoneal fluid cytlogy, extrafascial or radical hysterectomy with bilateral salpingooophorectomy, bilateral pelvic lymph node dissection and para-aortic lymph node sampling. All specimens were examined for tumor differentation, lymphovascular space invasion, depth of myometrial invasion, cervical, adnexal, and vaginal involvement pelvic and para-aortic lymph node metastases, and peritonneal fluid cytology. Statistical analysis was performed using the Pearson r correlation test to evaluate the correlation of preoperative serum CA 125 with the different surgicopathologic prognostic factors mentioned. A receiver operating characteristics curve (ROC) was used to determine the optimal cutoff value of preoperative CA 125. Sensitivity, specificity, accuracy and likehood ratios were calculated.
RESULTS: A total of 90 patients with endemetrioid type endometrial adenocarcinoma underwent co,plete surgical staging from October 2006 until July 2008. Of the different surgicopathologic prognostic factors, pre-operative serum CA 125 was demonstrated to be significantly correlated with deep myometrial invasion (correlation coefficient 0.24, p=0.02), adnexal metastasis (correlation coefficient 0.26, p=0.01), pelvic lymph node involvement (correlation coefficient 0.31, p=0.01) and para-aortic lymph node involvement (correlation coefficient 0.43, p 0.01. The test likewise significantly correlated with the presence of extrauterine disease with a coefficient of 0.26 (p=0.01). A cutoff value of 55 U/ml has been calculated to predict extrauterine spread with a sensitivity of 53.85% , specificity of 84.38%, and accuracy of 75.56%. Using this cutoff, the odds of the positive test is 3.44, and the odds of negative test is 0.54.
CONCLUSION: Pre-operative serum CA 125 has a statistically significant correlation with the presence of deep myometrial invasion, adnexal metastasis, pelvic and para-aortic lymph node involvement, and extrauterine disease at a determined cutoff value of 55U/mL. It is recommended that serum CA 125 determination be adopted as an integral part of the routine pre-operative work-up of patients with endometrial cancer.