The relationship between the number of circulating tumor cells and the prognosis in patients with esophageal squamous cell carcinoma.

Background: Esophageal cancer (EC) is one of the most common malignancies worldwide, with high morbidity and mortality rates. Circulating tumor cell (CTC) detection has become a novel approach in clinical study of EC. In this study, the relationship between CTCs/c-Kit expression of CTCs and the prognosis of EC patients was analyzed in EC.

Methods: A total of 43 EC patients with R0 resection were recruited for this study. The CanPatrol method was used to detect the CTC number in the peripheral blood of patients before and after operations, and the epithelial/interstitial type was classified. Multiple RNA in situ hybridization (RNA-ISH) was used to observethe c-Kit expression of CTCs. Post-operation follow-up occurred over 3 years. Logistic regression or the Cox proportional risk regression model was applied to analyze the relationship between CTC number, CTCs and disease characteristics, pathological stages and prognosis of patients with EC, and changes in CTCs before and after operations. c-Kit expression in different CTCs and the relationship between c-Kit expression and prognosis were also studied.

Results: The detection rate of CTCswas 81% (35/43). The detection rates of epithelial-, mixed- and stromal-type CTCs were 53%, 63%, and 33%, respectively. The 3-year overall survival rate was 67%. A CTC level of >2 indicated an increased risk of recurrence, metastasis, and death (P=0.018, 0.002, respectively). Following the operations, the total number of CTCs decreased in 29 cases. Of these, 6 cases were unchanged, and 8 cases demonstrated elevated CTCs. There was a significant difference in the positive rate of mixed-type CTCs before and after the operations. The rate of c-Kit expression in CTCs of EC patients was 46% pre-operation. No statistically significant correlations were found between c-Kit expression and postoperative recurrence/metastasis/survival of EC patients.

Conclusions: Preoperative CTC numbers, especially interstitial CTCs, were used as an auxiliary index in the prognosis of EC patients. The mRNA expression of c-Kit was detected in CTCs preoperatively in patients with EC, but no significant correlation between the c-Kit expression and the prognosis of EC patients was found.