Diagnostic value of liquid-based cytology and smear cytology in pancreatic endoscopic ultrasound-guided fine needle aspiration: A meta-analysis

BACKGROUND: Smear cytology (SC) using endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) is the established and traditional choice for diagnosing pancreatic lesions. Liquid-based cytology (LBC) is a novel alternative cytological method, however, the comparative diagnostic efficacy of LBC remains inconclusive. AIM: To examine the diagnostic efficacy of LBC and SC for pancreatic specimens obtained through EUS-FNA via a systematic review and meta-analysis. METHODS: A systematic literature search was performed using PubMed, EMBASE, the Cochrane Library, and Web of Science. The numbers of true positives, false positives, true negatives, and false negatives for each cytological test (LBC and CS) were extracted from the included studies. The pooled sensitivity and specificity and the area under the summary receiver operating characteristic curve (AUC) were calculated, and the AUC was compared by Tukey's multiple comparisons test. The quality of the included studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies II tool. RESULTS: A total of 1656 patients in eight studies were included. The pooled sensitivity and specificity and the AUC for LBC were 0.76 (95%CI: 0.72-0.79), 1.00 (95%CI: 0.98-1.00), and 0.9174, respectively, for diagnosing pancreatic lesions. The pooled estimates for SC were as follows: Sensitivity, 0.68 (95%CI: 0.64-0.71); specificity, 0.99 (95%CI: 0.96-100.00); and AUC, 0.9714. Similarly, the corresponding values for LBC combined with SC were 0.87 (95%CI: 0.84-0.90), 0.99 (95%CI: 0.96-1.00), and 0.9894. Tukey’s multiple comparisons test was used to compare the sensitivities and AUCs of the three diagnostic methods; statistically significant differences were found between the three methods, and LBC combined with SC was superior to both LBC (P < 0.05) and SC (P < 0.05). The pooled sensitivity and AUC did not change significantly in the sensitivity analysis. CONCLUSION: LBC may be sensitive than SC in the cytological diagnosis of pancreatic lesions, however, the superior diagnostic performance of their combination emphasizes their integrated usage in the clinical evaluation of pancreatic lesions.