Endoscopic ultrasonography-guided tissue acquisition for small solid pancreatic lesions: Does the size matter?

Endoscopic ultrasonography-guided tissue acquisition (EUS-TA) is now an established technique to obtain the pathological diagnosis of solid pancreatic lesions (SPLs), but the diagnosis of small SPLS by EUS-TA can still be difficult. We conducted a literature review and a meta-analysis on the diagnostic yield of EUS-TA according to the tumor size. In a meta-analysis of 33 studies with 6883 cases, a pooled odds ratio (OR) of sensitivity was significantly higher in SPLs of >20 mm (OR 1.64, p = 0.02) and in SPLs of >10 mm (OR 3.05, p = 0.01), but not in SPLs of >30 mm (OR 1.18, p = 0.46). The meta-analysis of accuracy also showed a similar trend: OR of 1.59 in SPLs of >20 mm (p < 0.01) and OR of 3.27 in SPLs of >10 mm (p < 0.01) and OR of 1.03 in SPLs of >30 mm (p = 0.87). The use of a 25-gauge needle tended to improve sensitivity in small SPLs, though not statistically significant: OR of 1.25 and 2.82 in studies with and without a 25-gauge needle (p = 0.08). The use of fine needle biopsy needles, slow pull method, and rapid on-site evaluation did not significantly improve sensitivity in small SPLs. EUS-TA for small SPLs, especially neuroendocrine neoplasms, is reported to have a high risk of adverse events. In summary, the diagnostic yield and safety of EUS-TA for small (<20 mm) SPLs still needs improvement, and the best needle and technique for small SPLs should be further investigated.