Diagnostic yield of liquid-based cytology in serial pancreatic juice aspiration cytological examination

Objectives: Serial pancreatic juice aspiration cytological examination (SPACE) via endoscopic retrograde cholangiopancreatography is a useful diagnostic method for early-stage pancreatic cancer, such as carcinoma in situ that are difficult to diagnose by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA). However, the diagnostic accuracy of SPACE is low, which is attributed to problems regarding specimen treatment. Hence, we evaluated the diagnostic efficacy of liquid-based cytology (LBC) in pancreatic juice cytology for pancreatic cancer. Methods: We retrospectively analyzed 24 patients with suspected pancreatic cancer that was difficult to diagnose by endoscopic ultrasound-guided fine needle aspiration who underwent SPACE using LBC between April 2017 and April 2021. Results: The most common reason for performing SPACE was localized stenosis of the main pancreatic duct without a mass. Eleven patients were diagnosed with malignancy after surgical resection, nine of whom had pancreatic ductal adenocarcinoma. Ten patients were diagnosed as benign after a follow-up of more than 1 year. The nine cases of malignancy were diagnosed before surgical resection by SPACE using LBC, with a sensitivity of 81.8% and specificity of 100%. The overall diagnostic accuracy was 91.7%. A total of 152 LBC examinations were performed via SPACE, with an adequate sample collection rate of 88.9%. No adverse events, including acute pancreatitis, occurred after endoscopic retrograde cholangiopancreatography. Conclusion: SPACE with LBC offers good diagnostic efficacy in patients with pancreatic cancer that is difficult to diagnose by endoscopic ultrasound-guided fine needle aspiration.