Usefulness of circulating tumor cell detection in pancreatic adenocarcinoma diagnosis.

Abstract

157 Background: For pancreatic tumor, guidelines recommend pancreatic cytology examination by EUS-FNA as the first diagnostic procedure in unresectable patients. Detecting CTCs in blood could play the role of a “liquid biopsy”. The usefulness of CTC detection in the clinical management of these patients has not been established yet. Here, we aimed to prospectively evaluate the accuracy of a diagnostic method based on CTC detection. Methods: All patients referred from January 2011 to March 2012 for EUS-FNA procedure in a context of pancreatic solid tumor diagnosis were prospectively enrolled after their consent. Prior EUS-FNA procedure a sample of peripheral blood was collected. CTCs were analyzed using the ScreenCell method. Cells were considered as tumoral if they met these morphological criteria: nuclear diameter >14 µ, anisocytosis, anisocaryosis, nuclear membrane irregularities, large nucleolus, clots of tumoral cells with platelets and fibrin. All analysis was performed by a pathologist blinded to the EUS-FNA results. The diagnosis of pancreatic adenocarcinoma was defined either by pathological evidence based on FNA or surgical specimen, or by clinical outcome with metastatic evolution and CA19.9 serum level rather than 10 fold normal value. Results: A total of 40 patients were included. A pancreatic adenocarcinoma was confirmed in 27/40 patients (68.3%). In 21 of the 27 patients, pathological proof of adenocarcinoma was obtained by EUS-FNA. For the diagnosis of adenocarcinoma, sensitivity and specificity of EUS-FNA were 77.8% and 100% respectively. The diagnostic accuracy of FNA was 85%. CTC detection was positive in 15 patients. Sensitivity and specificity were 55.5% (CI95% [40.1%; 70.9%]) and 100% (CI95% [75%; 100%]) respectively. The diagnostic accuracy of CTC was 70%. Metastatic statuses, lymph node involvement, vascular invasion, size of tumor and CA19.9 serum level were not statistically associated with CTC detection. Conclusions: We suggest that CTC detection be applied as first-line procedure before EUS-FNA in the strategy of pancreatic tumor diagnosis. With the implementation of this blood test on a routine basis, approximately one half of these patients could avoid invasive EUS-FNA procedure.