The diagnostic accuracy of 22-gauge and 25-gauge needles in endoscopic ultrasound-guided fine needle aspiration of solid pancreatic lesions: a meta-analysis

Background and study aims: It is uncertain if needle gauge impacts the diagnostic accuracy of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) of pancreatic mass lesions. Our aim was to use meta-analysis to more robustly define the diagnostic accuracy of EUS-FNA for pancreatic masses using 22G and 25G needles. Patients and methods: Studies were identified by searching nine medical databases for reports published between 1994 and 2011, using a reproducible search strategy comprised of relevant terms. Only studies comparing the overall diagnostic accuracy of 22G vs. 25G EUS needles that used surgical histology or at least 6 months clinical follow up for a gold standard were included. Two reviewers independently scored the identified studies for methodology and abstracted pertinent data. When required, the original investigators were contacted to provide additional data. Pooling was conducted by both fixed-effects and random effects models. Diagnostic characteristics (sensitivity, specificity, positive and negative likelihood ratios) with 95% confidence intervals (CIs) were calculated. Results: Eight studies involving 1292 subjects met the defined inclusion criteria. Of the 1292 patients, 799 were in the 22G group and 565 were in the 25G group (both needles were used in 72 patients). The pooled sensitivity and specificity of the 22G needle were 0.85 (95 % CI 0.82-0.88) and 1 (95 % CI 0.98-1) respectively. The pooled sensitivity and specificity of the 25G needle were 0.93 (95 % CI 0.91-0.96) and 0.97 (95 % CI 0.93-0.99) respectively. The bivariate generalized linear random-effect model indicated that the 25G needle is associated with a higher sensitivity (P=0.0003) but comparable specificity (P=0.97) to the 22G needle. Conclusions: This meta-analysis suggests 25G needle systems are more sensitive than 22G needles for diagnosing pancreatic malignancy.