A prospective comparison of endoscopic ultrasound-guided fine needle aspiration results obtained in the same lesion, with and without the needle stylet

Background and study aims: The effectiveness of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) with (S+) and without (S-) a stylet has never been compared. We prospectively compared the yield for malignancy and sample quality of S+ and S-EUS-FNA. Patients and methods: S+ or S-EUS-FNA was performed on consecutive solid lesions, with a 22-gauge needle, with systematic assignment of S+ or S-passes in a 1:2 ratio. Slides were read by a single, blinded cytologist and were rated for bloodiness, adequacy, and presence of malignancy. The yield for malignancy was compared only in lesions in which equal numbers of S+ and S-passes were performed. Results: A total of 309 passes (mean 2.3 passes/lesion, range 1-6, 82% adequate, 38% S+, 62% S-) were performed on 135 lesions (63% malignant, 42% nodes, 58% masses [79% pancreatic]) in 111 patients (mean age 62.9 years, range 30-86). In 46 lesions where an equal number (53 S+ and 53 S-) of passes was performed, there was no difference in the proportion of cases in which S+ FNA was equal to or better than S-FNA ([S+] 89% vs. [S-] 87%; P > 0.05). The results of the two methods agreed in 80% cases (kappa 0.60). The sensitivities for malignancy were: S+ 87% vs. S-83%, P > 0.05. Specificities were 100%. Sample adequacy was significantly lower in S+ passes (75% vs. 87%, P = 0.013), and sample bloodiness was significantly higher (75% vs. 52%, P < 0.0001). Conclusions: Use of the stylet with EUS-FNA does not increase the yield for malignancy and is associated with poorer sample quality. The value of the stylet for EUS-FNA is questionable and requires further investigation.