Combined use of radiotherapy and tyrosine kinase inhibitors in the management of metastatic non-small cell lung cancer: A literature review

The approval of tyrosine kinase inhibitors (TKIs) as first-line agents has revolutionised treatment of patients diagnosed with advanced non-small cell lung cancer (NSCLC) harboring targetable mutations, adding substantial overall survival (OS) benefit, compared to chemotherapy. However, the efficacy of these agents is inevitably diminished at a point in the disease course, either because of cellular resistance-mechanisms or due to affected pharmacokinetics, like low-central nervous system penetration. The aim of this article is to review existing evidence on the combined use of EGFR (epidermal growth factor)- or ALK (anaplastic lymphoma kinase)-specific TKIs and radiotherapy (RT) in advanced NSCLC setting, as an attempt to delay or overcome TKI-resistance and thus, to expand the time period during which patients derive benefit from a given line of targeted therapy. At present, combining RT with EGFR- or ALK-TKIs in the management of advanced, oncodriver-mutated NSCLC has shown quite promising results, with regards to PFS and OS, rendering prolongation of the TKI-derived benefit feasible, with generally tolerable toxicity. Future studies to confirm the observed efficacy and clarify possible safety issues as well as the appropriate treatment sequence and target volumes are needed, especially in the rapidly-evolving era of newer-generation TKIs.