Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is a highly sensitive and specific method in diagnosing solid pancreatic lesions. Rapid on-site evaluation (ROSE) of the aspirate by a cytopathologist improves specimen adequacy and diagnostic accuracy while reducing the number of needle passes. As this increases costs and implicates availability issues, the investigators aimed to evaluate the utility of ROSE by the endosonographer in guiding EUS-FNA of solid pancreatic lesions.

Consecutive patients with a solid pancreatic lesion were included. Endosonographer was submitted to a basic pancreatic cythpatology training programme at two institutitions. The patients were randomly allocated to the ROSE group - in which the number of needle passes required to obtain a sample suitable for cytopathologic categorization was established by the endosonographer's on-site evaluation - or to the non-ROSE group - in whom adequacy of the specimen was evaluated macroscopically and up to five needle passes could be performed, assuring sample adequacy. The gold standard was the final cytopathologist's diagnosis. The number of needle passes, procedure duration, specimen adequacy, diagnostic yield and adverse events rates were compared between groups and the performance measures of ROSE by endosonographer were determined.

Inclusion Criteria:

• solid pancreatic lesions detected by trans abdominal ultrasound or cross-sectional image (CT or MRI).
• formal indications to undergo EUS-FNA which were: differentiation between benign and malignant diseases, radiologic criteria of inoperability or unresectability, need for specific diagnosis which could modify therapeutic strategy and need for a diagnosis before neoadjuvant therapy.

Exclusion Criteria:

• a cystic or solid cystic aspect of the pancreatic lesion on above mentioned image methods
• lesions previously punctured on past EUS-FNA procedures
• American Society of Anesthesiologist (ASA) Physical Status Classification System IV or V
• cases of surveillance of solid pancreatic lesions
• severe coagulation disorder (platelet count < 50000 or International Normalized Ratio > 2,0)
• impossibility of previous suspension of antiplatelet agents (except acetylsalicylic acid) or anticoagulants (all)
• patient unwillingness to participate