Su1255 LARGER NEEDLE SIZE IS ASSOCIATED WITH IMPROVED SENSITIVITY, SPECIFICITY, AND ACCURACY IN THE DIAGNOSIS OF SOLID LESIONS: A RETROSPECTIVE ANALYSIS OF 22G VERSUS 25G FINE NEEDLE BIOPSY

Abstract

While endoscopic ultrasound (EUS)-guided fine needle biopsy (FNB) has become increasingly utilized for sampling solid gastrointestinal tract lesions, choice of needle size is often based upon anecdotal evidence. Therefore, the primary aim of this study was to compare the impact of needle size (22G versus 25G) on FNB sampling of solid lesions. This was a multi-center, retrospective observational study to evaluate the outcomes of EUS-guided FNB of solid lesions over a 3-year duration. Patient and lesion information as well as diagnostic test characteristics (i.e., sensitivity, specificity, positive predictive value [PPV], negative predictive value [NPV] and diagnostic accuracy), as well as adverse events were analyzed. Surgical resection pathology or immunohistochemistry were considered the reference standard for diagnostic yield. A bivariate model was used to compute diagnostic characteristics, and two-sample t-tests for binomial proportions were utilized to compare strategies. A total of 483 patients underwent EUS-guided FNB sampling of solid lesions (22G: n=303 and 25G: n=181). A majority of sampled lesions were subepithelial (50.72%), followed by pancreatic lesions (16.56%), lymph nodes (14.08%), and other lesions (18.64%). Mean age was 64.71 ±12.88 years with an average lesion size of 24.41 ±13.56 mm. Baseline diagnostic test characteristics are shown in Table 1. There was no difference in number of passes (P=0.24) or route of tissue acquisition (P=0.81) between groups. Overall, the 22G needle resulted in higher sensitivity (88.80% vs 71.94%; P<0.01), specificity (100.00% vs 97.62%; P=0.007), and accuracy (91.06% vs 77.90%; P<0.01) compared to the 25G needle. Larger needle size was associated with improved sensitivity (81.48% vs 56.52%; P=0.02) for pancreatic lesions. For subepithelial lesions, the 22G needle demonstrated superior sensitivity (90.65% vs 80.82%; P=0.03), specificity (100.00% vs 93.33%; P=0.001), and accuracy (91.72% vs 82.95%; P=0.04). Sensitivity (92.11% vs 60.00%; P=0.0005) and accuracy (95.38% vs 71.43%; P<0.01) were also higher for 22G sampling of other lesions as well. There was also a general trend for higher sensitivity and accuracy with the 22G needle for lymph nodes; however, this was not statistically significant (P=0.07 and P=0.08, respectively). No adverse events occurred in either group. Based upon this study, a larger 22G needle for FNB sampling of solid lesions was associated with improved sensitivity, specificity, and accuracy compared to a 25G FNB needle. These results suggest 22G be the preferred needle size for FNB of solid lesions.