Abstract 1490P
Background
Circulating tumor cells (CTCs) are tumor cells that are released into the bloodstream from the primary tumor or metastatic lesions, and have the potential to act as precursors of metastases in several types of cancer. Analysis of CTCs are non-invasive and real-time monitoring of cancer patients, thus now used as one of the liquid biopsy-based prognostic markers. In esophageal carcinoma (EC), a meta-analysis indicated that CTC-positive patients were associated with poor progression-free survival (PFS) and overall survival (OS). Japanese guideline recommends neoadjuvant chemotherapy (NAC) with 5FU/CDDP(FP) followed by curative surgery for stage Ⅱor Ⅲ esophageal squamous cell carcinoma (ESCC) and definitive chemoradiotherapy with FP for stageⅣa ESCC. We analyzed CTCs in EC patients to investigate whether NAC or chemotherapy (CT) have enough power to eliminate CTCs, or alter their phenotypes or not.
Methods
Peripheral blood samples from 31 EC patients before treatment and 25 patients of them after treatment were analyzed for the presence of CTCs with microfluidic chips. CTCs are defined as Pan-CK (+), DAPI (+) and CD45 (-), and classified into epithelial-CTCs and mesenchymal-CTCs by Vimentin expression by staining and scanning systems.
Results
Before treatment, CTCs were detected in 26 of 31 patients (84%) regardless of their clinical stage. Comparing 25 patients before and after treatment in each patient, their average number of CTCs increased from 9.92 to 11.12 in 4ml blood samples. There was no correlation between number of CTCs and clinical stage or clinical/pathological response or radiation therapy. The average ratio of epithelial/mesenchymal CTCs has changed only slightly from 0.45 to 0.47. The number and phenotype of CTCs did not affect the response of NAC or CT.
Conclusions
Our quantitative and qualitative analysis for CTCs shows that NAC and CT with FP does not have enough power to eliminate CTCs and alter their phenotypes.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.