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

Abstract

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.

Keywords: endoscopic ultrasound; fine needle aspiration; fine needle biopsy; pancreatic lesions.

FIGURE 1

Flowchart of study selection for meta‐analysis of EUS‐guided tissue acquisition according to the size of solid pancreatic lesions

FIGURE 2

Comparison of adequacy between SPLs of <20 mm and >20 mm. Odds ratio (OR) for SPLs < 20 mm compared with SPL > 20 mm is presented for each study (center of gray square) with 95% confidence interval (CI; horizontal line). Summary OR based on a meta‐analysis via the random‐effect model is presented at the bottom of each panel (center of black diamond) with 95% CI (the width of black diamond). p‐value for the Q‐statistic for between‐study heterogeneity is shown

FIGURE 3

Comparison of sensitivity. (a) Comparison between lesions of <30 mm and >30 mm. (b) Comparison between lesions of <20 mm and >20 mm. (c) Comparison between lesions of <10 mm and >10 mm Abbreviations: CI, confidence interval; OR, odds ratio.

FIGURE 4

Comparison of accuracy. (a) Comparison between lesions of <30 mm and >30 mm. (b) Comparison between lesions of <20 mm and >20 mm. (c) Comparison between lesions of <10 mm and >10 mm Abbreviations: CI, confidence interval; OR, odds ratio.

FIGURE 5

Subgroup analyses of sensitivity between small (<20 or 10 mm) and non‐small lesions. (a) Subgroups with and without 25‐gauge needles. (b) Subgroups with and without slow pull methods. (c) Subgroups with and without rapid on‐site evaluation. (d) Subgroups with and without fine needle biopsy Abbreviations: CI, confidence interval; FNB, fine needle biopsy; OR, odds ratio; ROSE, rapid on‐site evaluation.