Serial CTC Monitoring and Its Molecular Genetic Analysis during Treatment in Patients with Pancreatic Cancer.

Background/Aims Circulating tumor cells (CTCs) are cancer cells shed from either the primary tumor or its metastases, and they are regarded as the source of tumor recurrence and metastasis representing a poor prognosis in pancreatic ductal adenocarcinoma (PDAC). Thus, CTCs could provide a noninvasive alternative for diagnosis and assessment of the patient's stage and type of pancreatic cancer. In the present study, we investigated whether repeated collection and analysis of CTCs could be used to monitor disease progression or response to chemotherapy in PDAC patients. Methods Peripheral blood samples were serially collected before and after chemotherapy. To isolate CTCs from the millions of other blood cells, we used a lab-on-a-disc system equipped with fluid-assisted separation technology. Isolated CTCs from 3 mL of blood were immune-stained with EpCAM, cytokeratin, CD45, plectin-1 and DAPI, and then enumerated by using Bioview's automated imaging system. Results Total of 68 PDAC patients were enrolled as study patients. The median age of study patient was 67 years old and the median OS of study patients was 2.87 months. The clinical staging of study patients was the following; I (A, B) 5, II (A, B) 3, III 22 IV 38. The study patients received Gemcitabine based regimen FOLFIRNOX or TS-1 and the 14 patients (20.5%) could not receive chemotherapy due to the patients' wishes, old age or poor performance status. CTC were detected in 53 (78%) patients at the time of diagnosis. The number of CTCs dropped after 1st cycle of chemotherapy was observed in 38 patients (70%). Conclusions Understanding the biology and genetics of CTCs "cancer cells in transit" may give us unique insights into the mechanisms behind metastasis. Identification of CTC in peripheral venous circulation may allow us to characterize genomic signature of individual patient by a simple blood draw. [ABSTRACT FROM AUTHOR]