Objective: Analyses of tumor biopsy samples from non-small cell lung cancer patients with acquired epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI) resistance are expected to reveal the molecular mechanisms of resistance. However, due to limited tissue availability, performing such analyses can be challenging. We herein investigated the feasibility of tumor rebiopsy in this patient population.
Methods: From April 2004 to March 2013, 53 consecutive patients were treated with EGFR-TKIs at our department. A retrospective medical chart review was conducted among patients with progressive disease (PD) according to the Response Evaluation Criteria in Solid Tumors criteria, as assessed radiographically. Sites of progression were evaluated at the time of PD.
Results: Forty patients experienced PD at the following sites: isolated central nervous system (CNS) in 10 patients; isolated bone in five patients; isolated lymph nodes in two patients; the primary lesion in 10 patients; and systemic disease in 11 patients. Concerning the site of progression, 20 of the 40 patients had a lesion that could be accessed using endobronchial, transbronchial or percutaneous biopsy procedures. Among the 19 patients with oligoprogressive disease or CNS failure, the median overall survival was 24.1 months in eight patients who had received continuing treatment with EGFR-TKIs following radiotherapy and 16.8 months in 11 patients who received other therapies after PD.
Conclusion: In this study, few patients had a site of progression capable of being accessed using relatively noninvasive biopsy procedures. Further investigations are warranted to develop more optimal treatment strategies after PD in patients with oligoprogressive disease or CNS failure.