IntroductionPancreas cysts (PCs) are being diagnosed with increasing frequency given the widespread use of cross-sectional imaging in our health care system [1]. PCs can be broadly categorized as either non-neoplastic or neoplastic, with the latter being estimated as high as 13.5 % in the general population [2]. Accurate diagnosis and risk stratification of neoplastic cysts are crucial as to provide guidance for the most appropriate management strategy.The optimal diagnostic approach to PCs remains unclear as there is currently no single test that can reliably differentiate non-neoplastic PCs from those lesions with malignant potential or harboring malignancy. Given the well-recognized limitations of imaging alone [2-4], EUS-guided fine-needle aspiration (EUS-FNA) for cytology and cyst fluid analysis is the commonly performed guideline endorsed test for aid with diagnosis and risk stratification [4][5][6][7][8][9][10]. FNA cytology is often limited by the scant cellularity within the cyst fluid [11,12]. While cyst fluid carcinoembryonic antigen (CEA) has been traditionally used to differentiate mucinous versus non-mucinous PCs [13], it has ABSTR AC T Background and study aims Accurate diagnosis and risk stratification of pancreatic cysts (PCs) is challenging. The aim of this study was to perform a systematic review and meta-analysis to assess the feasibility, safety, and diagnostic yield of endoscopic ultrasound-guided through-theneedle biopsy (TTNB) versus fine-needle aspiration (FNA) in PCs.
MethodsComprehensive search of databases (PubMed, EMBASE, Cochrane, Web of Science) for relevant studies on TTNB of PCs (from inception to June 2019). The primary outcome was to compare the pooled diagnostic yield and concordance rate with surgical pathology of TTNB histology and FNA cytology of PCs. The secondary outcome was to estimate the safety profile of TTNB. Results: Eight studies (426 patients) were included. The diagnostic yield was significantly higher with TTNB over FNA for a specific cyst type (OR: 9.4; 95 % CI: [5.7-15.4]; I 2 = 48) or a mucinous cyst (MC) (OR: 3.9; 95 % CI: [2.0-7.4], I 2 = 72 %). The concordance rate with surgical pathology was significantly higher with TTNB over FNA for a specific cyst type (OR: 13.5; 95 % CI: [3.5-52.3]; I 2 = 48), for a MC (OR: 8.9; 95 % [CI: 1.9-40.8]; I 2 = 29), and for MC histologic severity (OR: 10.4; 95 % CI: [2.9-36.9]; I 2 = 0). The pooled sensitivity and specificity of TTNB for MCs were 90.1 % (95 % CI: [78.4-97.6]; I 2 = 36.5 %) and 94 % (95 % CI: [81.5-99.7]; I 2 = 0), respectively. The pooled adverse event rate was 7.0 % (95 % CI: [2.3-14.1]; I 2 = 82.9).Conclusions TTNB is safe, has a high sensitivity and specificity for MCs and may be superior to FNA cytology in riskstratifying MCs and providing a specific cyst diagnosis.
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