Correlation between the positive expression of circulating tumor cells and clinicopathological characteristics in well-differentiated nonfunctional pancreatic neuroendocrine tumors performed on CellSearch platform

Objective: to investigate the feasibility of the circulating tumor cells applied in well-differentiated nonfunctional pancreatic neuroendocrine tumors (NF-pNETs) and present the pilot study of its clinical value using CellSearch platform. Method: From September 2014 to March 2016, 15 consecutive patients (7 males) who were pathologically diagnosed as well-differentiated NF-pNETs were enrolled in this study. 7.5 ml blood from the peripheral vein were drawn, detected and analyzed through the CellSearch system. The clinical characteristics, tumor grade, CTCs counts of each patient were recorded and statistically compared. Results: Of the 15 enrolled patients, 46.67% were males. All of the patients were NF-pNETs (26.67% G1, 73.33% G2) and 6 of them had liver metastases (LM). The median size of the primary lesion was 2.14 cm, and the median ki-67 index was 6.27%. CTC were detected in 53.33% of patients, the mean count was 2.2 CTCs (median 1). For all the recruited patients, compared with the control group, patients with lymph metastases (P=0.003), tumor size larger than 2 cm (P=0.020) and elevated CgA level (P=0.001) preoperatively were likely to have higher capture rate of tumor cells. Conclusion: CTCs detection from the peripheral blood is practical in well-differentiated NF-pNETs, which has the potential to suggest the prognosis. Further detection and exploration need to be continued.