Procedures
STRICTURE
ERCP procedures were performed by or under direct supervision of a dedicated interventional endoscopist using standard techniques. Because of the diameter (9 French) of the dense brush, all patients in the intervention group underwent concomitant sphincterotomy. In the control group, sphincterotomy was performed at the discretion of the endoscopist. Cytology was obtained by pulling the brush back and forth through the stricture for 10 times in both groups. Hereafter, the brush was covered with the sheet and pulled back. Brushes were placed in a standard cytology vial and the cover of the brush was flushed in the vial to optimize cellular yield. The samples were evaluated by pancreatobiliary-dedicated pathologists as part of standard care. Deoxyribonucleic acid (DNA) mutation analysis, immunohistochemical staining, and central reading of the brush cytology samples were not standardly performed. Brush cytology samples were classified according to the Bethesda score [