Endobronchial ultrasound-guided re-biopsy of non-small cell lung cancer with acquired resistance after EGFR tyrosine kinase inhibitor treatment.

Background: Few studies assessed the use of endobronchial ultrasound (EBUS)-guided re-biopsy for detecting the T790M mutation after epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) failure.

Methods: A total of 2996 EBUS procedures were performed during the study period (January 2019-June 2022). In total, 44 consecutive patients who underwent EBUS-guided re-biopsy (56 procedures) for detecting the T790M mutation were analyzed. The success rates and T790M mutation frequencies were analyzed according to the re-biopsy site and EBUS method. Multivariate logistic regression analyses were used to identify factors affecting the likelihood of the T790M mutation.

Results: The success rates for the mutation analyses using EBUS with a guide-sheath (EBUS-GS), EBUS guided transbronchial needle aspiration (EBUS-TBNA), and EBUS-GS with EBUS-TBNA for re-biopsy were 80.6% (29/36), 93.3% (14/15), and 100% (5/5), respectively. Patients who underwent lymph node biopsy using EBUS-TBNA had an increased rates of the T790M mutation compared with those undergoing lung biopsy using EBUS-GS (EBUS-TBNA, 60.0%; EBUS-GS with EBUS-TBNA, 40.0%; EBUS-GS, 11.1%; p < 0.001). In multivariate analysis, the use of a first-generation EGFR-TKI (odds ratio [OR], 4.29; 95% confidence interval [CI], 1.05-17.58; p = 0.043) was associated with occurrence of the T790M mutation. Re-biopsy of the metastatic site tended to be associated with a higher T790M mutation rate. Mild hemoptysis occurred in 3.6% (2/56) of the patients.

Conclusions: EBUS-guided re-biopsy can be used for detecting the T790M mutation in patients who failed EGFR-TKI therapy. The T790M mutation frequency differed according to the re-biopsy site. The use of a first-generation EGFR-TKI was an independent predictor of the T790M mutation.