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NSCLC — SCE Medical Oncology MCQ

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HardLung CancerNSCLCSCE Medical Oncology

A 55-year-old man presents with a 4 cm right upper lobe mass. CT-guided biopsy confirms TTF-1 positive adenocarcinoma. Comprehensive NGS reveals an uncommon EGFR mutation: exon 18 G719X. What is the treatment implication?

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Correct answer: E — This mutation is best treated with afatinib (second-generation TKI) which has broader EGFR mutation coverage

Uncommon EGFR mutations (G719X, L861Q, S768I) account for approximately 10-18% of EGFR-mutated NSCLC. Afatinib has the broadest label covering uncommon mutations (NICE TA517, LUX-Lung 2/3/6 pooled analysis) with response rates of approximately 60-70%. Osimertinib also has activity against some uncommon mutations but is specifically approved for exon 19 del and L858R. First-generation TKIs have lower activity against uncommon mutations.

Reference: NICE TA517 Afatinib for EGFR mutation-positive NSCLC; Yang et al Lancet Oncol 2015; ESMO 2024 NSCLC Guidelines