The Use of a Stylet in Endoscopic Ultrasound with Fine-Needle Aspiration: A Systematic Review and Meta-Analysis

Background: Endoscopic ultrasound with fine-needle aspiration (EUS-FNA) is the most efficacious way to collect specimens from a solid lesion adjacent to the gastrointestinal tract and is performed with an internal stylet during puncture. However, its reinsertion into the needle is time-consuming. Controversy surrounds whether quality of cytology specimen improves with stylet use. We performed a meta-analysis comparing the use of stylet versus no stylet with EUS-FNA of gastrointestinal-related masses. Methods: Multiple databases were searched from inception until April 28, 2016. Discordant findings from independent extractions were reviewed by at least 2 investigators. Methods were executed as per the standards of the Cochrane Collaboration. Primary outcomes assessed were diagnostic adequacy of individual specimen samples, accuracy, and yield. Secondary outcomes included overall diagnostic accuracy of per-malignant lesion, cellularity, contamination, and bloodiness of the sample, and adverse events. Results: Five randomized control trials were identified comparing stylet versus no stylet use, which enrolled 504 patients, evaluated 537 lesions, and 1914 distinct specimens. There was no difference in diagnostic adequacy [risk ratio (RR)=1.00; 95% confidence interval (CI), 0.95-1.07], accuracy (RR=0.98; 95% CI, 0.90-1.06), or yield (RR=0.96; 95% CI, 0.89-1.03). No stylet use was favored in per-lesion malignant diagnosis (RR=0.85; 95% CI, 0.76-0.96). There was no difference in representative cellularity, contamination, or bloodiness of specimens obtained with or without stylet use. Conclusions: Stylet use confers no significant advantage in diagnostic adequacy, accuracy, yield, contamination, bloodiness, or cellularity over no stylet. We reinforce that no stylet use may be used preferentially in EUS-FNA as a more convenient technique and is favored with a higher per-lesion malignant diagnosis.