Significance of Circulating Tumor Cells in Nonsmall-Cell Lung Cancer Patients: Prognosis, Chemotherapy Efficacy, and Survival.

Introduction We aimed to evaluate whether circulating tumor cells (CTCs) were the prognostic indicator responsible for chemotherapy and survival of NSCLC patients. Methods Between January 2013 and September 2017, CTCs in the peripheral blood of histologically confirmed stages III and IV NSCLC patients were collected. Blood specimens were obtained on the first day of treatment, chemotherapy 2 and 4 cycles, or targeted therapy 1 and 2 months for CTCs detection. The positive CTC status was defined as one or more CTCs per 7.5 ml. Results 100 patients were enrolled, of which 48 patients (48%) were identified to be CTC positive at baseline. A higher CTC-positive rate was observed in stage IV NSCLC patients than stage III patients (69% vs. 40%, P=0.015). CTC cluster was significantly correlated with disease control rate. Based on the baseline CTC number, patients were divided into low CTC levels (<4 CTCs, LL) and high CTC levels (≥4 CTCs, HL). There was clinically significant shorter median OS and OS (overall survival) and PFS (progression-free survival) in HL group patients (P < 0.001). Conclusions The positive association between the CTC number and survival suggested that the baseline CTC number and changes during treatment might be the prognostic information of response rate and overall survival in Chinese patients suffering stage III/IV NSCLC.