Complete Remission to Afatinib in a Patient Harboring a Novel Epidermal Growth Factor Mutation in De Novo Small-Cell Lung Cancer: A Case Report

Clinical Practice Points

• •Small cell lung cancer (SCLC) is a highly aggressive disease closely linked to tobacco consumption and therefore very rare in patients who never smoked.
• •SCLC can occur de novo or from the histologic transformation of non-small cell lung cancer (NSCLC) due to acquired TKI (tyrosine kinase inhibitor) resistance.
• •In patients with de novo SCLC, epidermal growth factor receptor (EGFR) mutations are extremely rare and treatment strategies have not been established yet. Molecular biomarker testing is currently not mandatory in lung cancers that lack an adenocarcinoma component.
• •We report on a case of EGFR-mutated de novo SCLC with 2 activating EGFR mutations in exon 18 (G719C, E709V) in a 56-year-old woman who responded to afatinib with good tolerability.
• •While G719X has been already found in rare cases of de novo SCLC, E709V has not been described in SCLC yet.
• •It might be worth considering next generation sequencing (NGS) profiling in patients who lightly or never smoked with SCLC to detect genetic alterations with clinical impact.