Our findings suggest that plasma analyses prior to initiation of second-line osimertinib therapy may be clinically relevant.

This study, by reporting a large series of patients, provides real-life data, indicating that a higher allele frequency of epidermal growth factor receptor (EGFR) mutations, particularly EGFR-activating mutations, in plasma circulating tumor DNA before start of osimertinib treatment is associated with poor prognosis.

Further studies on the clinical utility of liquid biopsy are needed.