Endoscopic Ultrasound Guided Fine-Needle Aspiration for Solid Lesions in Chronic Pancreatitis: A Systematic Review and Meta-Analysis

Background Patients with chronic pancreatitis (CP) are at a higher risk of developing pancreatic adenocarcinoma compared the general population with an estimated 5% risk of developing pancreatic cancer in 20 years. Endoscopic ultrasound fine needle aspiration (EUS-FNA) of solid pancreatic lesions (SPL) has an excellent sensitivity (85-90%) and specificity (98-100%) for diagnosing pancreatic malignancy. However, data on the performance characteristics of EUS-FNA in CP are mixed. Aims In this systematic review and meta-analysis, we aim to examine data from published studies on the diagnostic performance of EUS-FNA in detecting pancreatic malignancy in CP. Methods We conducted a comprehensive search of MEDLINE, Cochrane, EMBASE, Scopus databases for studies published in English language that reported performance characteristics of EUS-FNA for SPL up to November 2020. Two reviewers independently conducted screening, full text review and data extraction according to the PRISMA guidelines. Quality of included studies was assessed using the risk of bias in non-randomized studies of interventions (ROBINS-I) tool. The parameters of interest were sensitivity, specificity, negative, and positive likelihood ratios. Cochran Q test and I statistics were used to determine the between-study heterogeneity. Funnel plots were used to describe publication bias. Results A total of 6753 studies were identified on initial search. Studies that reported EUS-FNA of cystic pancreas lesions were excluded. Eight studies met the inclusion criteria. Seven studies were retrospective, and one was prospective. A total of 593 patients with CP underwent EUS-FNA for SPL. The pooled sensitivity of EUS-FNA was 65% (95% CI 52.6-75.6%, I-2 = 44%), specificity was 96.8% (75-99.7%, I-2 = 89%), negative likelihood ratio (NLR) 41.4 (11.1-149.6, I-2 = 70%), positive likelihood ratio (PLR) 24.1 (2.8-208, I-2 = 90%). The pooled data from seven studies that compared 901 non-CP vs. 127 CP showed that the sensitivity of EUS-FNA in diagnosing pancreatic malignancy was 91.5 vs. 65.3% [OR (95% CI) 5.5 (2.9-10.2), I-2: 31.8%]. The specificity pooled from six studies [333 non-CP vs. 357 CP] was 95.9% vs. 82.4%, [OR (95% CI) 1.3 (0.2-9.8), I-2 = 73%]. The risk of bias was serious in one study, low in four studies and moderate in three studies. Conclusion This pooled meta-analysis shows a low sensitivity of EUS-FNA in diagnosing malignancy in CP patients with SPL in comparison to patients without CP. Modalities such as EUS-fine needle biopsy have high sensitivity and specificity for diagnosing pancreatic cancer and should be considered in patients with CP and suspected pancreatic malignancy.