Contributions of bronchoscopic microsampling in the supplemental diagnosis of small peripheral lung carcinoma

Background Making a preoperative pathologic diagnosis in patients with small lung nodules remains challenging. We have developed a new, noninvasive bronchoscopic microsampling probe to examine biochemical substances in epithelial lining fluid. We used this probe to measure tumor markers in fluid from tissues surrounding lung nodules less than 30 mm in diameter to test its adjunctive diagnostic utility in lung cancer. Methods In 12 patients, epithelial lining fluid was collected in triplicate or duplicate from tissue within 2 cm of small peripheral lung nodules and from the contralateral lung. The diagnosis of adenocarcinoma was surgically confirmed in all patients. Fifteen patients without lung cancer served as controls. Concentrations of carcinoembryonic antigen, cytokeratin fragment 19, and sialyl SSEA-1 were measured in the fluid. Results Carcinoembryonic antigen and cytokeratin fragment 19 concentrations were significantly higher in fluid near the nodules (median, 8.7 and 87.2 ng/mg, respectively) than on the contralateral sides (median, 1.5 and 3.7 ng/mg, respectively) or in fluid collected from the controls (median, 2.0 and 2.8 ng/mg, respectively). Conclusions Measurements of carcinoembryonic antigen and cytokeratin fragment 19 collected by our microsampling probe may be a useful diagnostic adjunct in patients with small peripheral lung nodules.