229PLIQUID BIOPSY BASED ON CIRCULATING TUMOUR CELLS (CTC) DETECTION IS A DIAGNOSTIC AND PROGNOSTIC MARKER IN PATIENTS WITH PANCREATIC SOLID TUMOURS

ABSTRACT Aim: The pancreatic cytology by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is considered as thestandard procedure for the diagnostic of pancreatic tumour. We recently showed that detection of circulating tumour cells (CTC) hada diagnostic accuracy of 70% for pancreatic adenocarcinoma (Am J Gastroenterol 2013;108:152-155). The aim of the study was toevaluate both diagnostic and prognostic impact of CTC detection in an extended series of patients referred for a EUS-FNA for apancreatic solid tumour. Methods: It was a single center study including all consecutive patients referred from 01/2011 to 07/2013 for a EUSFNAprocedure in a context of pancreatic solid mass. EUS-FNA was performed with a 22 gauge needle and analysed by twopathologists. A 10 ml peripheral blood sample was collected in each patient before the EUS-FNA procedure. Samples were filteredusing the ScreencellsCyto method®, stained with Giemsa and analyzed by a cytologist blinded to clinical data and FNA results. The CTC detection was positive according to the presence of the following parameters: nuclear diameter > 7m, anisocytosis, membraneirregularities, presence of a large nucleolus. Results: A total of 69 patients were included. Amon them, 57 (83%) have a confirmed pancreatic tumours corresponding to 47primitive adenocarcinoma, 4 others primitive tumours and 6 metastatic lesions. The sensitivity and the specificity of EUS-FNA was83% and 100%, respectively. CTC were positive in 36/69 (52%) patients. The sensitivity and specificity of CTC was respectively64.4% and 73.3% in patients with pancreatic cancer and 64.1% and 81.8% in patients with all types of cancer. The presence of CTCwas significantly associated with the diagnostic of cancer (p = 0.01) and with the presence of distant metastases (p = 0.004). In contrast,tumour size, arterial involvement and CA19-9 serum level were not associated with CTC. The 18 months survival rate wassignificantly lower in patients with positive CTC as compared to those without detectable CTC (33 vs 44%, p = 0.03). Conclusions: Ours results highlighted that liquid biopsy based on circulating tumour cells (CTC) detection may be a diagnosticand prognostic marker in patients with pancreatic solid tumours. Disclosure: All authors have declared no conflicts of interest.