Diagnostic yield of malignancy during EUS-guided FNA of solid lesions with and without a stylet: a prospective, single blind, randomized, controlled trial

Background: Use of a stylet during EUS-guided FNA (EUS-FNA) is believed to improve the quality and diagnostic yield of specimens.

Objective: To compare samples obtained by EUS-FNA with (S+) and without (S-) a stylet for diagnostic yield of malignancy and cytological characteristics.

Design: Randomized, controlled trial.

Setting: Tertiary referral center.

Patients: Consecutive patients referred for EUS-FNA of solid lesions.

Intervention: EUS-FNA; the number of passes was determined by lesion site (6 pancreas/others and 4 lymph nodes).

Main outcome measurements: Diagnostic yield of malignancy and degree of cellularity, specimen adequacy, contamination, and amount of blood.

Results: One hundred patients were prospectively enrolled in this randomized, controlled trial and the sites of EUS-FNA were the pancreas, 58; lymph node, 25; and other, 17. The overall diagnosis was malignancy in 56, benign in 30, suspicious/atypical in 7, and inadequate specimen in 7 lesions. There were 550 passes made (275 with a stylet and 275 without a stylet). Interim analysis demonstrated no difference in the diagnostic yield of malignancy (94 passes with a stylet [34.2%] vs 110 without a stylet [40%], P = .2) and in the proportion of inadequate specimens (57 with a stylet [20.7%] vs 64 without a stylet [23.3%], P = .2). There was no difference with regard to cellularity (P = .83), contamination (P = .31), number of cells (P = .25), and amount of blood (P = .6). Similar results were noted in a subgroup analysis based on lesion site. Applying the rules of futility, the study was terminated.

Limitations: Subjectivity in cytopathologists' assessment, endosonographer not blinded.

Conclusions: There was no difference in the diagnostic yield of malignancy or proportion of inadequate specimens between passes with and without a stylet. These results suggest that the use of a stylet does not confer any advantage during EUS-FNA.