Resectable Esophageal Adenocarcinoma: The Influence of Multimodal Therapy on the Prevalence and Enumeration of Circulating Tumor Cells in Comparison With Conventional Response Evaluation in a Feasibility Study

Little is known of the prevalence and clinical relevance of CTC in EAC, with the available data arising from heterogeneous patient populations using varied detection methods; but they are promising tools to improve staging and prediction of treatment response to perioperative and operative therapy.

The limited reports on resectable EAC use the epithelial-antibody dependent CellSearch method for CTC isolation and report a CTC-positivity rate of only 15-18% in non-pre-treated patients but with clinical relevance. It is thus needed to evaluate the relevance of CTC in the context of multimodal treatment courses.

This pilot study will investigate the CTC in the blood of patients with resectable EAC treated with multimodal therapy. Data on prevalence and enumeration of CTC will be generated. Two CTC isolation methods will be investigated, the established and expensive surface-antibody-dependent CellSearch method, and the antibody-independent and less expensive isolation by size (ISET; ScreenCell) method. The ISET method will additionally be investigated in healthy controls to get data on specificity.

The study can accomplish several goals through the use of two CTC detection platforms: 1) to determine the prevalence and number of CTC in resectable EAC under multimodal treatment, and 2) to investigate the potential role of CTC in predicting response to treatment and prognosis before neoadjuvant treatment, after neoadjuvant treatment and before operation as well as after the operation.

The primary hypothesis is that the enumeration of the CTC correlates with tumor burden and will reflect the response to treatment. To date the response to treatment is assessed with a combination of CT-morphologic, endoscopic, clinical (dysphagia) and finally histology. This assessment is used as control.