The ability of isolated fine needle aspiration of lymph nodes to provide complete diagnostic information without necessitating additional diagnostic procedures: A retrospective cohort study.

Abstract

e18341 Background: Diagnostic fine needle aspiration (FNA) of pathologically enlarged lymph nodes is a relatively safe, quick, and well-tolerated procedure that can be quickly analyzed to identify the presence of malignant cells. Though proven very useful to assess for the presence or absence of malignancy for staging purposes, the procedure’s ability to provide adequate tissue to appropriately diagnose a new malignancy and perform all necessary predictive and prognostic studies has not been explored. Methods: We retrospectively reviewed clinical records of patients who underwent FNA of a pathologically enlarged lymph node for the purpose of obtaining a tissue diagnosis at our institution between January 2010 and December 2015. We then assessed the percentage of patients that required a second diagnostic procedure independent of the FNA result. Procedures done for therapeutic purposes (such as resection) were not counted as a second procedure. We also collected data on the type of procedure used to obtain FNA, patient history of malignancy, and whether the diagnosis was benign or malignant. Results: We identified 594 FNA procedures that fit the study criteria. Of these, 277 (46.6%) required an additional diagnostic procedure. Among the 277 that required a second procedure, 237 (85.6%) were benign and 40 (14.4%) were malignant on primary FNA (P < 0.0001). Of the 237 benign FNAs that required a second procedure, 84 (35.5%) had the diagnosis changed to malignant after the second procedure (P < 0.001). There was no difference between procedure used to obtain the FNA (bronchoscopy, endoscopy, percutaneous) or patient age in the need for a second procedure. Conclusions: Though fine needle aspiration is a useful procedure for establishing the presence or absence of metastatic disease, our analysis suggests that the ability of the procedure to reliably diagnose or provide sufficient tissue for ancillary testing is limited. Nearly half of the patients in this study were subjected to the risks, cost, and diagnostic delay associated with a second procedure.