What, When, and How of Biomarker Testing in Non-Small Cell Lung Cancer.

Biomarker testing is recommended for all patients diagnosed with non-small cell lung cancer. At a minimum, testing should include the mutations/fusions , and the protein programmed death ligand-1 (PD-L1), because FDA-approved therapies are available for these alterations. Other actionable molecular findings include rearrangements, mutations, and exon 14 alterations. If adequate testing was not performed at treatment initiation, molecular testing should be performed before administration of subsequent lines of therapy. In patients with -mutant lung cancer, when resistance develops, physicians should seek to identify the T790M mutation using plasma and tissue assays, because osimertinib therapy is available for this mutation.