[The Significance of Surgical Biopsy in Case of the Resistance to Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitors for the Treatment of Postoperative Recurrence of Lung Cancer].

To evaluate the clinical features of patients who developed resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) administered for postoperative recurrence of lung cancer, we assessed eight patients who underwent surgical biopsy or sampling for the detection of T790M mutation under general anesthesia from 2017 to 2019 in our hospital. All 8 patients had undergone lobectomy with nodal dissection for lung cancer of pathological stageⅠB/Ⅲ/Ⅳa (4/3/1 patients). The median disease-free survival was 29 months (range:11~110 months). The recurrence site was the lung in six patients including malignant pleural effusion in one of six, and two pleural disseminations. All eight patients received gefitinib as first-line treatment. The median age at surgical biopsy was 75 years (range:66~86 years). We performed pleural biopsy in 2 patients, partial lung resection in 5 patients, and pleural effusion sampling in 1 patient in whom our attempt to perform partial lung resection failed because of severe adhesion between the lung and chest wall. T790M mutation was observed in 7 patients( 85.7%) and the treatment by osimertinib in 6 patients was effective in 5 patients( 83.3%). Surgical biopsy is useful for detecting gene mutations in patients resistant to EGFR-TKIs.