Clinical significance of detection of circulating tumor cells after colorectal cancer surgery

Abstract

Objective To evaluate the relationship between peripheral blood circulation tumor cells (CTCs) and clinical pathological variables, tumor recurrence and metastasis and prognosis in patients with colorectal cancer (CRC). Methods From January 2016 to July 2017, the clinical pathological variables of 99 newly-diagnosed and histopathologically confirmed CRC patients from the Ninth People's Hospital affiliated to Shanghai jiao tong university medical school were collected. There were 66 males and 33 females, aged 37-79 years old. The CTCs enumeration and the serum carcinoembryonic antigen (CEA) levels were measured between 4 and 8 weeks after surgery or before adjuvant therapy. All patients were followed up for survival. Statistical differences in characteristics and CTCs enumeration, including gender, age, primary site, tumor differentiation, primary invasive depth (T stage), regional lymph node invasion (N stage), distant metastasis (M Staging), TNM staging, observation of patient survival, COX proportional hazards regression model for single-factor and multivariate analysis of progression-free survival and overall survival. Results The positive rate of CTCs in 99 CRC patients was 60.6% (60/99), and the range of CTCs was 0-24 (4.909±5.518). CTCs in patients with positive expression and CTCs count stage T1+ T2, T3, N0, M0, Ⅰ-Ⅱ period, the CEA<5 ng/mL were lower than those of T4, N1+ N2, M1 period, Ⅲ-Ⅳ period, the CEA acuity 5 ng/mL, low differentiation, and the differences were statistically significant (all P values<0.05). The patients were followed up for 3 to 20 months, and 22 patients died (22/99, 22.2%), including 21 CTCs positive; 32 patients with disease progression (32/99, 32.3%), of which 29 were positive for CTCs. Univariate analysis showed that CTCs, N stage, M stage, tumor stage, and high serum CEA levels were the influencing factors of poor progression-free survival (all P values<0.05). CTCs, N stage, M stage, primary tumor stage and high CEA levels were the influencing factors of poor overall survival (all P values<0.05). CTCs and distant metastasis were independent prognostic factors for poor progression-free survival and overall survival in CRC patients (HR=5.418, 2.254, 95% confidence interval: 1.595-8.403, 1.227-7.986, all P values<0.05). Conclusions In patients with postoperative CRC, CTCs enumeration might be a predictive factor for tumor recurrence and metastasis. CTCs positive might be associated with a reduced survival in patients with colorectal cancer. Key words: Colorectal neoplasms; Circulating tumor cells; Survival; Predictive factor