Some studies showed the ctDNA concentration is associated with poor prognostic results [10, 11], while other studies assessed the predictive and prognostic value of cfDNA concentration or EGFR mutation in NSCLC patients treated with chemotherapy [12], but these studies are limited to obtain a few genes, not reflecting the full spectrum of mutations emerging during the treatment. The gene discussed is EGFR; the disease is non-small cell lung carcinoma.