Outcomes of research biopsies in clinical trials of EGFR mutation-positive non-small cell lung cancer patients pretreated with EGFR-tyrosine kinase inhibitors

Background/purpose Research biopsies (RBs) are crucial for developing novel molecular targeted agents. However, the safety and diagnostic yields of RBs have not been investigated in EGFR mutation-positive non-small cell lung cancer (NSCLC) patients pretreated with epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs). Methods We searched the medical records of NSCLC patients who participated in lung cancer clinical trials and underwent mandatory RBs between 2012 and 2014 at our institution. Only patients with EGFR mutation-positive NSCLC pretreated with at least 1 EGFR-TKI were enrolled. Results Of 140 enrolled patients, 73 (52.1%) and 59 (42.1%) had exon 19 deletions and exon 21 L858R mutation, respectively. Before RBs, 108 (77.1%), 83 (59.3%), and 36 (25.7%) patients had been treated with gefitinib, erlotinib, and afatinib, respectively. Computed tomography-guided percutaneous core needle biopsy was the most frequently used modality among 181 RBs performed (50.8%), followed by ultrasonography-guided (32.0%) and endoscopic RBs (16.0%). The most common RB sites were the lung (69.6%), pleura (8.8%), and liver (6.1%). Pathologic examinations revealed malignant cells in most RB specimens (72.9%). Complications due to RBs included pneumothorax (11.6%), bleeding (6.1%), and infection (1.1%). Only 1 patient required chest tube placement for pneumothorax, and 2 patients underwent endotracheal intubation because of bleeding. Conclusion RBs in this patient population were generally safe. Pneumothorax was the most frequent complication; bleeding, while infrequent, increased the risk of severe events. The diagnostic yields and complications of any particular modality should therefore be discussed with prospective clinical trial participants.