<i>EGFR</i> mutational landscape in non–small cell lung cancer: A 10-year experience of a national reference laboratory in Colombia (2014–2023).

Abstract

e20565 Background: Non-small cell lung cancer (NSCLC) accounts for approximately 80% of lung cancer cases globally. Targeted therapies for patients harboring epidermal growth factor receptor (EGFR) mutations have revolutionized survival; however, ethnic and geographic variability in mutation prevalence remains understudied in Latin America. This study represents a decade-long effort to characterize the EGFR mutational landscape in a large Colombian cohort, addressing a critical regional data gap and providing a baseline for precision oncology. Methods: A retrospective observational study was conducted on 1,782 patients with NSCLC whose samples were centralized and analyzed at a national reference laboratory (UDHO) in Cali, Colombia (2014–2023). EGFR status was determined via real-time PCR (qPCR) using IVD/CE certified kits capable of detecting 42 mutations across exons 18–21. Testing utilized formalin-fixed paraffin-embedded (FFPE) tissue (n = 1,555) and plasma (n = 227, implemented in 2016). Strict quality protocols, including a minimum 10% neoplastic content and automated software analysis (LSR), ensured technical reproducibility. Results: The cohort showed a balanced sex distribution (50.5% female, 49.5% male) with ages ranging from 16 to 95 years. A total of 474 mutations were identified. Mutational prevalence was significantly higher in plasma (42%) compared to FFPE tissue (28%). Key findings include: Predominant Mutations: Exon 19 deletions (51.9%–60.8%) and L858R (19.9%–31.8%) were the most frequent. Resistance Profile: Identification of T790M co-mutations, most notably Exon 19 del + T790M (4.5% female; 6% male). Healthcare Barrier: 92.9% of studies were industry-sponsored, with only 7.1% covered by public health entities. The invalid result rate remained low, reflecting high pre-analytical standards. Conclusions: This longitudinal study—one of the most robust in the Andean region—confirms a high prevalence of actionable EGFR mutations in Colombian NSCLC patients. The data underscore that liquid biopsy is a vital diagnostic tool for increasing mutation detection rates in Latin America. These results highlight a critical "access gap," where precision diagnostics rely almost exclusively on pharmaceutical sponsorship, necessitating urgent public health policy shifts to ensure sustainable oncology care and health equity in the region.