Histologic and molecular characterization of lung cancer with tissue obtained by electromagnetic navigation...

Electromagnetic navigation bronchoscopy (ENB) is a catheter-based adjunct to standard bronchoscopic techniques for the sampling of lung lesions. We sought to evaluate the adequacy of ENB-obtained samples for histologic subtyping of lung cancer, epidermal growth factor receptor (EGFR) mutations, and echinoderm microtubule-associated protein-like 4-anaplastic lymphoma kinase (EML4-ALK) translocations.

We retrospectively analyzed consecutive patients who underwent ENB for the diagnosis of lung lesions between 2008 and 2011. In those proven to be a primary lung cancer by ENB, tissue adequacy for histologic subtyping was recorded. Accuracy was determined by comparison with resected specimens when available. Tissue adequacy for EGFR mutation and/or EML4-ALK analyses was also reviewed.

Sixty-five ENB cases resulted in a diagnosis of lung cancer. Tissues obtained were adequate for histologic subtyping in all 65 cases. Forty-three (66.2%) were diagnosed with adenocarcinoma, 19 (29.2%) with squamous cell carcinoma, 3 (4.6%) with small cell carcinoma. In 51 cases (78.5%), subtyping was performed by morphology alone, whereas 11 (21.5%) required immunohistochemical staining. Sixteen of 65 tumors underwent surgical resection. Concordance of histologic subtyping between ENB and surgical specimens was 87.5% (14 tumors). ENB-obtained samples from 15 patients with adenocarcinoma were sent for EGFR mutation analysis, of which 14 (93.3%) were adequate. Samples from 2 patients were evaluated for EML4-ALK gene rearrangements, both of which were adequate for analysis.

ENB is effective at obtaining tissue samples adequate for histologic subtyping, EGFR mutation, and EML4-ALK translocation analysis.