8: Tumour molecular profiling and quantitative detection of circulating biomarkers in patients with lung cancer

Circulating DNA in solid organ cancers—analysis and clinical application

“…5,8 Interestingly, in anecdotal reports of patients with lung cancer there are examples in which the radiological assessment of response and that of the circulating biomarker differ. 7,21 However, there is not enough yet known about the mechanisms controlling ctDNA dynamic change, and how well radiological and ctDNA biomarkers correlate with each other or how well ctDNA predicts outcome, to understand whether there is potential for ctDNA to be used instead of rather than in addition to radiological tests. These data are beginning to emerge in larger studies.…”

“…23 However, the most obvious example that has been well studied is the propensity of patients with EGFR mutant lung cancer to relapse with the so-called gatekeeper mutation-EGFR T790M-that confers resistance to first-line EGFR TKIs. 12,13,16,21 It is now clear that T790M can readily be detected in the blood on relapse, and, in data presented at a recent meeting it was demonstrated that blood-based detection of T790M was as predictive of response to a second-generation TKI drug as a tissue-based detection of T790M through re-biopsy. 24 Further, a recent publication has emphasised the potential of using ctDNA to define novel modes of resistance to new targeted treatments without the need for tissue samples.…”