Abstract LB-180: Prognostic analysis of invasive circulating tumor cells (iCTCs) to monitor epithelial ovarian cancer

Abstract

Abstract Purpose: Cancer antigen 125 (CA125) is recognized as the leading biomarker in monitoring Epithelial Ovarian Cancer (EOC). More recently, invasive circulating tumor cells (iCTCs) have been introduced as a biomarker for metastatic potential. The goal of this research is to compare this biomarker with CA125 to determine the response to surgery and chemotherapy. Experimental Design: We compared clinical parameters with serial assays for iCTCs and CA125 in 129 fresh blood and 169 serum samples, respectively, from 31 patients who were receiving surgery and chemotherapy. iCTCs were capable of ingesting matrices (Cell Adhesion Matrix CAM+) and identified using positive tumor markers, Epi (EPCAM and CA125 or seprase and CD44), and negative selection markers, which exclude Epi-positive hematopoietic lineage (HL) cells, and enumerated by flow cytometry. iCTCs and CA125 levels were measured at time point less than 3-days apart. Results: A significant correlation was identified between changes in iCTC counts and CA125 levels (r=0.67, P<0.001) in the 83 samples collected prior to and after surgery and therapy. CA125 levels, but not iCTCs, were significantly reduced after surgery. During therapy, a significantly stronger concordance with clinical status was noted for decreasing values (specificity, 93.8% CA128; 90.6% iCTCs) compared with increasing values (sensitivity, 61.3% CA125; 83.9% iCTCs). Notably, increases in iCTCs, not CA125, were associated with increased risks for progressive disease (P<0.001). In the 8 patients who had >4 serial samples during therapy, changes in iCTC counts provided earlier measure of therapy response than CA125. Conclusion: This analysis showed that iCTC assay compared favorably with CA125 to monitor the response of chemotherapy in EOC patients, whereas changes of CA125 correlated better with reduced tumor burden after surgery. Citation Format: Wen-Tien Chen, Huan Dong, Qiang Zhao, Jie Yang, QIAO ZHANG, Stanley Zucker, Michael L. Pearl. Prognostic analysis of invasive circulating tumor cells (iCTCs) to monitor epithelial ovarian cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr LB-180. doi:10.1158/1538-7445.AM2014-LB-180