To detect circulating tumor cells (CTC) in patients with colorectal carcinoma and to evaluate the relationship among CTC, clinic-pathological characteristics and prognosis of colorectal carcinoma.

Peripheral blood samples were obtained from 109 patients with colorectal carcinoma in Department of General Surgery, Beijing Friendship Hospital, Capital Medical University from April 2014 to October 2016. There were 60 male and 49 female patients, aging from 33 to 86 years with a mean age of (65±10) years.CTC were detected using density-gradient centrifugation and immunofluorescence staining. χ² test, Fisher exact test and rank-sum test were used to analyze the relation between positive rate of CTC and clinical characteristic, respectively. The correlation analysis of CTC and common tumor markers was detected by χ² test and Spearman test. The overall survival of patients was analyzed by Kaplan-Meier curve and Cox proportional hazard model.

CTC were found in 71 of the 109 patients with colorectal carcinoma. The presence of CTC was significantly correlated with N stage (Z=4.422, P=0.035) and M stage (χ²=4.424, P=0.049). However, CTC was not significantly correlated with age, sex, tumor location, tumor size, differentiation, T stage, Ki-67 and TNM stage (P>0.05). Meanwhile, there was significant correlation between CTC and carcino-embryonic antigen (CEA) (χ²=4.897, P=0.027; r=0.212, P=0.027) indicated by χ² test and Spearman correlations analysis. The positive rate of CTC was higher than that of CEA (χ²=15.45, P=0.000). Survival analysis suggested that positive CTC was poor for overall survival in colorectal cancer with adjusted HR as 3.023(95%CI: 1.330 to 6.872, P=0.008).

CTC is helpful to early diagnosis tumor recurrence and metastasis. Hence, combined multiple tumor markers, including the CTC as common indicators of tumor diagnosis, relapse and metastasis could effectively improve the accuracy of diagnosis.

Colorectal neoplasms; Neoplastic cells, circulating; Early diagnosis