[New biopsy at lung cancer progression: rational treatment of resistant lung cancer].

Nowadays, patients with advanced non-small cell lung cancer harbouring a driver mutation undergo targeted treatment. This results in profound tumour responses but inevitably induces resistance after approximately 9 to 12 months. In this article we consider the importance and clinical implications of taking new biopsies to retrieve information regarding resistance mechanisms. There is a shift in the use of other modalities such as radiotherapy and surgery in patients with oligometastatic disease, producing long-lasting responses. This is illustrated by three different patient cases: one with an EGFR exon 21 mutation, obtaining a T790M mutation upon treatment; another with a BRAF V600 mutation initially treated with chemotherapy and later with targeted therapy; and, finally, a patient with an ALK translocation with progression on crizotinib treatment, responding to subsequent alectinib therapy. The latter developed oligometastatic disease that was treated with radiotherapy, resulting in a complete response for at least 2 years.