Small-cell lung cancer circulating tumour cell derived explants

Paired blood samples were used for CTC enumeration with CellSearch Technology and for the generation of CDX models. Demographic and clinical data were analysed for differences between patients whose blood samples generated a CDX and those whose samples did not. A total of 231 paired blood samples were taken from 147 patients; 45 CDXs were generated from 34 patients. CTC number was higher in samples with a CDX than in those without a CDX (P=0.001). Successful progression samples had a lower CTC number than successful baseline samples (P=0.026). Metastatic burden was higher in patients who samples generated a CDX (P≤0.001). They also had shorter PFS and OS outcomes (P≤0.001).

Findings showed that CTC number correlates with CDX success, but a specific CTC phenotype may be more important. CTCs at progression may have a more aggressive phenotype than those at baseline, and CTCs may play a role in the widespread dissemination of SCLC. CDXs seemed to represent the SCLC patient population. This is important when translating knowledge gained by studying CDXs into clinical practice. Further genomic and phenotypic analysis of subpopulations of CTCs may provide further insight.