Improved preoperative risk stratification with CA-125 in low-grade endometrial cancer: a multicenter prospective cohort study

The global obesity epidemic has great impact on the prevalence of low-grade endometrial carcinoma. The preoperative tumor serum marker cancer antigen 125 (CA-125) might contribute to improved identification of high-risk patients within this group. The study aimed to investigate the prognostic value of CA-125 in relation to established preoperative prognosticators, with a focus on identifying patients with poor outcome in low-grade endometrial carcinoma (EC) patients. Prospective multicenter cohort study including all consecutive patients surgically treated for endometrial carcinoma in nine collaborating hospitals from September 2011 until December 2013. All preoperative histopathological diagnoses were reviewed in a blinded manner. Associations between CA-125 and clinicopathological features were determined. Univariable and multivariable analysis by Cox regression were used. Separate analyses were performed for preoperatively designated low-grade and high-grade endometrial carcinoma patients. A total of 333 patients were analyzed. CA-125 was associated with poor prognostic features including advanced International Federation of Gynecology and Obstetrics (FIGO) stage. In multivariable analysis, age, preoperative tumor and CA-125 were significantly associated with disease-free survival (DFS); preoperative grade, tumor type, FIGO and CA-125 were significantly associated with disease-specific survival (DSS). Low-grade EC patients with elevated CA-125 revealed a DFS of 80.6% and DSS of 87.1%, compared to 92.1% and 97.2% in low-grade EC patients with normal CA-125. Preoperative elevated CA-125 was associated with poor prognostic features and independently associated with DFS and DSS. Particularly patients with low-grade EC and elevated CA-125 represent a group with poor outcome and should be considered as high-risk endometrial carcinoma.