Fine-needle aspiration of small pulmonary nodules yields material for reliable molecular analysis of adenocarcinomas

Introduction: Early molecular characterization with Kirsten rat sarcoma factor, epidermal growth factor, and anaplastic lymphoma kinase are critical to manage pulmonary adenocarcinoma. Fine-needle aspiration (FNA) of lesions <2 cm are routine in our institution and are used in molecular analysis. We report our experience. Materials and methods: We searched our databank for primary pulmonary adenocarcinomas diagnosed by FNA between January 2009 and April 2013. Size of the lesion aspirated, molecular results, and sample source (FNA versus surgical specimen) were recorded. We compared the frequency of mutations identified by FNA versus surgical specimens and the frequency of mutations in lesions by size (<1 cm, 1-cm, >2 cm). Results: We identified 397 primary pulmonary adenocarcinomas. Molecular studies were requested by the clinician in 89 (22%) of primary adenocarcinomas. FNAs were used in 55 cases; 51 (93%) yielded sufficient material for molecular studies; surgical tissue were used in 34 cases; 33 (97%) yielded sufficient material for molecular studies. The insufficient specimens came from 2 FNAs of 0.6 cm nodules, an FNA of a 2 cm nodule, and a core biopsy. Conclusions: FNA was adequate for molecular analysis of small nodules. In nodules greater than 0.6 cm, the adequacy is comparable to surgical tissue. There was no statistically significant change in mutation rate by size (53%-58%). Importantly, FNA of small lesions for cytological diagnosis and molecular analysis is encouraged by our data and experience in order to provide early treatment.