Clinical outcomes and survival in patients with NSCLC and EGFR exon 20 mutations: Evidence from real-world clinical practice in a retrospective study in Galicia

Begoña CAMPOS^1*Martín Emilio Lázaro Quintela²María Carmen Areses Manrique³Cristina Azpitarte Raposeiras⁴Jorge García-González^5,6,7Francisco Javier Afonso Afonso⁸Manuel Fernández-Bruno⁹Natalia Fernández Núñez¹Raquel Romero Van der Schoot¹Lucía Santomé Couto¹⁰

• ¹Lucus Augusti Universitary Hospital, Lugo, Spain
• ²Vigo University Hospital Complex, Vigo, Spain
• ³Complexo Hospitalario Universitario de Ourense, Ourense, Spain
• ⁴Complejo Hospitalario Universitario de Pontevedra, Pontevedra, Spain
• ⁵Complejo Hospitalario Universitario de Santiago de Compostela, Santiago de Compostela, Spain
• ⁶Centro de Investigacion Biomedica en Red de Cancer, Madrid, Spain
• ⁷Instituto de Investigacion Sanitaria de Santiago de Compostela, Santiago de Compostela, Spain
• ⁸Complejo Hospitalario Universitario de Ferrol, Ferrol, Spain
• ⁹Complexo Hospitalario Universitario A Coruna, A Coruña, Spain
• ¹⁰Povisa Ribera Hospital, Vigo, Spain

Background: Non-small cell lung cancer (NSCLC) with mutations in epidermal growth factor receptor exon 20 (EGFR Ex20Ins) is rare and resistant to conventional tyrosine kinase inhibitors (TKIs), limiting treatment options. This retrospective study in Galicia (Spain) evaluated the clinical characteristics, treatment response, and survival of patients with NSCLC and EGFR Ex20Ins. Methods: Data from patients diagnosed between 2013 and 2023, confirmed by next-generation sequencing (NGS) or polymerase chain reaction (PCR), were included. Overall survival (OS), progression-free survival (PFS), and the incidence of serious adverse events were assessed. Results: Of the 43 patients in the present study, 39 had metastatic disease and were considered for survival analysis. Among patients with metastatic disease, the median OS was 14.6 months (95% CI: 7-20 months), and the median PFS was 7.4 months (95% CI: 3-12 months) with first-line therapy (1L). Patients treated with platinum-based chemotherapy in the 1L achieved a median PFS of 9.8 months (95% CI: 3-27 months), whereas those receiving TKIs achieved a median PFS of 3.4 months (95% CI: 1-12 months). No significant differences in treatment response were found according to age or sex. Conclusions: The results show the limited effectiveness of TKIs in patients with EGFR Ex20Ins and highlight the need for specific therapies. Platinum-based chemotherapy performed better in preventing disease relapse.