Treatment sequences in EGFR mutant advanced NSCLC

Common EGFR gene mutations (exon 19 deletion and L858R in exon 21) are the most frequent cause of actionable genomic alterations in non-small cell lung cancer (NSCLC) patients. The introduction of EGFR tyrosine kinase inhibitors (TKIs) as 1st-line treatment of advanced stages of the disease has changed the natural history of the disease and extended survival rates, establishing third generation TKIs as a new standard of frontline treatment. Nonetheless, the prolongation of overall survival remains modest, as multiple escape pathways and tumor increasing heterogeneity inevitably develop over time. Several strategies are currently developed to improve these patients' outcome: prevent the emergence of resistance mechanisms by therapeutic combinations introduced from the first line, act on the residual disease at the time of maximum response to 1st line treatment, develop therapeutic strategies at the time of acquired resistance to TKIs, either dependent on the resistance mechanisms, or agnostic of the resistance pathways. Recent advancements in treatment combinations have shown promising results in prolonging progression-free survival, but often at the cost of more severe side effects in comparison with the current standard of care. These emerging new treatment options open up possibilities for diverse therapeutic sequences in the management of advanced NSCLC depending on common EGFR mutations. The impact on the disease natural history, the patients' survival and quality of life is not yet fully understood. In this review, we propose an overview of published and forthcoming advances, and a management algorithm considering the different first-line options, integrating the clinical and biological parameters that are critical to clinicians' decision-making process.