The application of nano-enrichment in CTC detection and the clinical significance of CTCs in non-small cell lung cancer (NSCLC) treatment

Circulating tumor cells (CTCs) are an independent prognostic marker in non-small cell lung cancer (NSCLC). CTC numbers are closely related to early diagnosis, clinical stage, therapy surveillance, and prognosis of NSCLC. We used a more efficient nano-enrichment method to detect CTCs in NSCLC patients and explored the clinical value of CTCs. The results showed that CTC numbers in stage IV cases were significantly higher than those in stage I, II or III cases. The number of CTCs in poorly-differentiated cases was significantly higher than that in well-differentiated cases. During six chemotherapy cycles, the average CTC number decreased from 5.8/7.5 ml in cycle #1 to 2.4/7.5 ml in cycle #4 and remained at almost the same level from 4 to 6 cycles. CTC numbers in patients with EGFR mutations was significantly higher than those in patients with no mutations. The average progression free survival (PFS) in the favorable group (CTC ≤ 5/7.5 ml) was 11.3 months, which was longer than that in the unfavorable group (CTC > 5/7.5 ml, 7.2 months). In conclusion, the assessment of NSCLC cannot be performed using a single CTC analysis. The clinical value is more significant in the continuous analysis of CTC data, as well as the cross-validation of other indexes and imaging results.