Circulating tumor cells can predict the prognosis of patients with non-small cell lung cancer after resection: a retrospective study

Background The development of metastasis is the primary cause of death in patients with non-small cell lung cancer (NSCLC). However, identifying those NSCLC patients who will have loco-regional or distant disease recurrence after surgery is still challenging. Circulating tumor cells (CTCs) can accurately reflect the impact of micro-metastasis of tumor cells in circulating blood on patients' treatment and prognosis. The aim of the present study was to explore the value of preoperative CTC concentration in predicting postoperative metastasis and recurrence risk in patients with NSCLC. Methods This study enrolled 347 patients with stage I-IIIA NSCLC. The CTCs were isolated using folate receptor (FR) positivity from peripheral blood samples before surgery, and then enriched and analyzed. Patients were divided into two groups for retrospective survival analysis based on the geometric mean of CTC concentration. The primary study endpoint was recurrence-free survival. Spearman's correlation was used to evaluate the relationship between CTC concentration and clinical characteristics of NSCLC patients. A nomogram based on the multivariate Cox regression model was developed to predict recurrence and metastasis in the NSCLC patients. The performance of the nomogram was evaluated using the concordance index, calibration curve, and Hosmer-Lemeshow test. Results The median follow-up time was 38 months. Preoperative CTC concentration was not significantly related to tumor-node-metastasis staging (P>0.05) and was an independent prognostic factor for NSCLC patients [hazard ratio (HR), 5.489; 95% confidence interval (CI): 2.660-11.326, P<0.001]. The nomogram based on preoperative CTC concentration had a concordance index value of 0.82. Validation revealed that the nomogram possessed excellent predictive ability and calibration. Conclusions Preoperative CTC concentration is an independent and sensitive biomarker of prognosis in patients with NSCLC. Our nomogram based on preoperative CTC concentration is an effective and non-invasive tool for predicting the recurrence and metastasis of NSCLC.