Prospective Evaluation of Fine Needle Aspiration (FNA) Versus Fine Needle Capillary Sampling (FNC) On Specimen Quality and Diagnostic Accuracy in EUS-Guided Biopsy

Abstract

Background and Aim: Standard EUS-FNA utilizes 10cc of suction to draw tissue into the biopsy needle. Recent data has suggested that high power suction may improve sample yield. Studies from the radiology literature, however, suggests that FNC (i.e. FNA without suction) may yield a higher quality sample secondary to less trauma to the tissue and less blood. The aim of our study was to compare a technique of FNA with that of FNC during EUS tissue sampling to determine if there is a difference in specimen quality and diagnostic accuracy. Methods: From May 2005 to October 2005 30 consecutive patients who were referred to our center for EUS-FNA were included. The average age was 65 yrs (range 32-77 yrs) with 10F and 20M. The study group was comprised of: pancreatic masses (12); lymph nodes (16) and submucosal masses (2). There were 17 malignant and 13 benign lesions in the study. EUS was carried out using the Olympus GF-UC140P linear array echoendoscope and FNA was performed using a 22-gauge cytology needle. The echoendoscope was positioned so that sampling could be performed along the longest possible lymph node or mass diameter. In each patient, the first two passes were made without suction (FNC). The needle was vigorously flushed with 20 cc of normal saline. Two addition passes were then performed using the same needle after 10 cc of suction was applied. Additional passes for diagnostic purposes were made as necessary at the discretion of the endosonographer, but these were not included in the study. No on-site cytopathologist was present. A single blinded pathologist later evaluated each set of slides for background blood or clot, amount of cellular material, degree of cellular degeneration and degree of cellular trauma based on a previously studied scale (scores 0-2 for each parameter). The results were compared using the Wilcoxon Matched-Pairs Signed-Ranks Test. Results: There was no statistically significant difference in any of the criteria evaluated between FNA and FNC (p = 0.7). Pooled analysis of all criterias and overall accuracy were similar (p = 0.3) In the subgroup of patients with pancreatic masses and lymph nodes there was no difference (p = 0.7). Conclusions: Our data suggests that FNC is, at best, equivalent to FNA in the quality and accuracy of the obtained specimen during EUS tissue acquisition. Although more data is needed, our preliminary data suggests that future research should focus on higher amounts of suction for tissue acquisition rather than FNC.