Repeat biopsy in lung cancer patients with EGFR mutation

Neal Navani, MA, MBBS, MRCP, MSc, PhD, University College London, London, UK, explains the need for re-biopsy in non-small cell lung cancer (NSCLC) patients with progressive disease.

Approximately 15% of NSCLC patients have tumour-associated EGFR mutations and are usually treated with EGFR Tyrosine Kinase Inhibitors (TKIs) in first-line. However, after 9-12 months, the disease starts to progress again in the majority of patients. Of these patients, those carrying a T790M mutation in the EGFR gene can benefit from treatment with osimertinib (Tagrisso ®), as demonstrated recently in the AURA3 trial.

Dr Navani addresses how the T790M mutation can be detected in patients with progressive NSCLC, in order to inform treatment decisions. He discusses ways to test for this mutation: cell-free DNA assays and advanced biopsy techniques.

Cell-free DNA assays are performed using blood samples, and therefore, are convenient for patients and relatively fast. However, the test sensitivity is approximately 60-70% and is lower in patients whose disease only progresses within the lungs.

In terms of biopsy techniques, two key techniques are used: endobronchial ultrasound (EBUS) and CT-guided biopsies. Dr Navani explains that together, these two techniques allow sampling from virtually anywhere within the thorax in order to obtain tissue to analyse for T790M mutation.

Recorded at the 2017 meeting of the British Thoracic Oncology Group (BTOG) in Dublin, Ireland.

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