Targeting EGFR-Mutant Non-Small Cell Lung Cancer in Asia: An Update on Monotherapy and Combination Therapy With EGFR Inhibitors.
EGFR-mutant lung cancer represents a major subtype of non-small cell lung cancer in Asia, with particularly high prevalence in never-smokers, women, and patients with adenocarcinoma histology. Although this clinicopathologic enrichment has been recognized for more than two decades, the mechanisms underlying the excess frequency of EGFR-mutant disease in Asian populations remain only partially understood. Accumulating evidence suggests a multifactorial basis involving host genetic susceptibility and diversity, endogenous mutational processes and exogenous exposures such as ambient particulate matter. In particular, recent genomic and experimental studies support a tumour-promotion framework in which inflammatory microenvironmental cues may facilitate the outgrowth of pre-existing oncogenic clones, while mutational signatures provide genomic footprints of these processes. In parallel, the treatment landscape for EGFR-mutant non-small cell lung cancer has evolved substantially with successive generations of EGFR tyrosine kinase inhibitors (EGFR-TKIs), leading to marked improvements in survival. However, acquired resistance remains inevitable in most patients with advanced disease and is driven by both genetic and non-genetic mechanisms, including secondary EGFR alterations, bypass pathway activation, TP53-associated genomic instability, adaptive mutagenesis, and drug-tolerant persister states. These insights have provided a strong rationale for combination strategies beyond EGFR-TKI monotherapy. In this review, we summarize current understanding of the epidemiology and biological basis of EGFR-mutant lung cancer in Asia and discuss the preclinical rationale and emerging clinical evidence supporting combination approaches with chemotherapy, anti-angiogenic agents, and EGFR/MET-directed therapies.