Feasibility of re-biopsy and EGFR mutation analysis in patients with non-small cell lung cancer

BackgroundIn cases of EGFR-tyrosine kinase inhibitor (TKI) failure, re-biopsy may be useful to understand resistance mechanisms and guide further treatment decisions. However, performing re-biopsy is challenging because of several hurdles. We assessed the feasibility of re-biopsy in advanced non-small cell lung cancer (NSCLC) patients in real-world clinical practice. MethodsWe retrospectively reviewed the clinical and pathologic data of advanced NSCLC patients who experienced disease progression after previous treatment with EGFR-TKIs at a single tertiary hospital in Korea between January 2014 and December 2016. Re-biopsy specimens included small biopsy, surgical tissue, or liquid-based cytology. EGFR mutation was tested using peptide nucleic acid-mediated clamping PCR. ResultsOf the 230 NSCLC patients that experienced progression after EGFR-TKI therapy, 105 (45.7%) underwent re-biopsy. Re-biopsy was successfully performed in 94 (89.5%) patients, and 11 patients were diagnosed with no malignancy. The complication rate was 8.6%, including seven cases of pneumothorax. EGFR mutation testing was performed on 75 patients using re-biopsy specimens. Of the 57 patients who had sensitizing mutations at diagnosis, T790M mutations were found in 19 (33.3%), while 38 (66.7%) had no T790M mutation. Multivariate analysis showed that the re-biopsy group was younger (P=0.002) and exhibited a previous response to EGFR-TKIs (P<0.001). ConclusionRe-biopsy in advanced NSCLC is feasible in real world clinical practice, particularly in younger patients and those who achieved a previous response to EGFR-TKIs.