22-Gauge biopsy needles have a better histological diagnostic yield in the discrimination of specific pancreatic solid neoplasms

Background: To overcome the limitations of using cytological specimen alone for the diagnosis of challenging pancreatic lesions, biopsy needles have been developed to procure histological specimens during EUS, especially for the discrimination of several specific pancreatic tumors requiring adequate histological samples. The aim of this study was to compare the diagnostic yield of EUS-guided 22-gauge (G) fine needle aspiration (FNA) needles and 22G fine needle biopsy (FNB) needles for sampling pancreatic masses.

Methods: We conducted a retrospective study of all EUS-guided sampling performed between November 2012 and April 2016. 422 cases sampled with a 22G FNA needle (N = 254) or a 22G FNB needle (N = 168) were recruited for this study. The specimen quality analyses, technical characteristics, accuracy, sensitivity, specificity, positive predictive values (PPVs), and negative predictive values (NPVs) for the pancreatic masses were reviewed and compared.

Results: There was no significant difference in the procurement of adequate histological specimens (75.0% vs. 79.5%; p = .277) or the presence of diagnostic histological specimens (71.3% vs. 77.4%; p = .155) between FNA and FNB groups, respectively. There were also no significant differences in the accuracy, sensitivity, specificity, PPVs, or NPVs of the cytological, histological, and overall analyses for FNA and FNB groups in the diagnosis of pancreatic malignancy. However, 22G biopsy needles demonstrated a better histological diagnostic yield in the discrimination of pancreatic adenocarcinoma and non-adenocarcinoma pancreatic neoplasms than 22G FNA needles (69.8% vs. 57.9%, p = .033).

Conclusions: 22G FNB needle demonstrated a better histological diagnostic yield in the differentiation between pancreatic adenocarcinoma and non-adenocarcinoma pancreatic neoplasms.