Adequacy of Core Needle Biopsy Specimens and Fine-Needle Aspirates for Molecular Testing of Lung Adenocarcinomas

OBJECTIVES: Molecular testing of lung adenocarcinomas for epidermal growth factor (EGFR) mutations and an anaplastic lymphoma kinase (ALK) translocation is important to guide directed therapy with tyrosine kinase inhibitors. The goal of this study was to determine whether transthoracic computed tomography-guided core needle biopsy (CNB) and fine-needle aspiration (FNA) biopsy specimens were equally suitable for molecular testing. METHODS: We determined the percentage of 52 CNB and 120 FNA specimens that contained sufficient paraffin-embedded tumor tissue for EGFR, KRAS, and ALK testing over a period of 2 years. We correlated sample sufficiency with the sampling method, tumor size, biopsy operator, pathologist assessing the adequacy of the sample, and the number of FNA passes performed. RESULTS: Univariate analysis showed that CNB specimens provided a significantly higher number of samples sufficient for molecular testing than did FNA specimens (67% vs 46%; P = .007) and that one operator achieved a significantly higher percentage of sufficient FNA specimens. Binomial logistic regression found sufficiency of FNA samples to correlate with tumor size (P = .015) but not operator. CONCLUSIONS: When paraffin-embedded tissue is used for molecular testing of lung cancer, CNB specimens are more likely than FNA specimens to provide adequate tissue for molecular testing. Obtaining a sufficient FNA specimen depends on the tumor size and the individual performing the biopsy.