 A side-by-side comparison of EGFR mutation analysis in DNA extracted from circulating tumour cells CTCs versus cfDNA from plasma suggested that mutational analysis of CTCs captured on the CellSearch platform was low by comparison with the frequency of EGFR mutations identified in plasma.11 However, this limitation might be related to the CellSearch platform used,11 because other CTC platforms eg, CTC biochip have greater sensitivity and specificity for EGFR mutational analyses.12 New technologies, such as next generation sequencing and digital PCR Figure 1, which can permit more precise quantification of cfDNA and also the CTCs, offer opportunities to design more appropriate treatments. Longitudinal analyses of EGFR and other mutations in cfDNA and CTCs might well prove to be an ideal non-invasive technique to be included in the oncologists repertoire at the time of assigning or monitoring treatment in patients with NSCLC. 