Core biopsy needle versus standard aspiration needle for endoscopic ultrasound-guided sampling of solid pancreatic masses: a randomized parallel-group study

Background and study aims: An endoscopic ultrasound (EUS)-guided fine needle biopsy (EUS-FNB) device using a core biopsy needle was developed to improve diagnostic accuracy by simultaneously obtaining cytological aspirates and histological core samples. We prospectively compared the diagnostic accuracy of EUS-FNB with standard EUS-guided fine needle aspiration (EUS-FNA) in patients with solid pancreatic masses. Patients and methods: Between January 2012 and May 2013, consecutive patients with solid pancreatic masses were prospectively enrolled and randomized to undergo EUS-FNB using a core biopsy needle or EUS-FNA using a standard aspiration needle at a single tertiary center. The specimen was analyzed by onsite cytology, Papanicolaou-stain cytology, and histology. The main outcome measure was diagnostic accuracy for malignancy. The secondary outcome measures were: the median number of passes required to establish a diagnosis, the proportion of patients in whom the diagnosis was established with each pass, and complication rates. Results: The overall accuracy of combining onsite cytology with Papanicolaou-stain cytology and histology was not significantly different for the FNB (n=58) and FNA (n=58) groups (98.3% [95% CI 94.9%-100%] vs. 94.8% [95% CI 91.9%-100%]; P=0.671). Compared with FNA, FNB required a significantly lower median number of needle passes to establish a diagnosis (1.0 vs. 2.0; P<0.001). On subgroup analysis of 111 patients with malignant lesions, the proportion of patients in whom malignancy was diagnosed on the first pass was significantly greater in the FNB group (72.7% vs. 37.5%; P<0.001). Conclusions: The overall accuracy of FNB and FNA in patients with solid pancreatic masses was comparable; however, fewer passes were required to establish the diagnosis of malignancy using FNB.