AMPULLARY ADENOMAS GREATER THAN 20 MM IN SIZE HAVE HIGHER RISK OF RECURRENCE COMPARED TO SMALLER LESIONS

Introduction
Lesions of ampulla of Vater can be treated by endoscopic ampullectomy which can obviate the need for surgery. Data regarding effectiveness for endoscopic ampullectomy especially for larger lesions is lacking. We aimed to assess the impact of polyp size on recurrence on subsequent ERCP procedures following initial ampullectomy.
Methods
After approval of the study from local IRB, patients treated with endoscopic ampullectomy at our tertiary care referral center were included in the study. Charts were obtained using the relevant billing and ICD10 codes from electronic medical records and were then individually reviewed by a group of researchers to extract relevant information. Patients were divided into two groups based on polyp size; ≤20 mm group, compared to >20 mm polyp size group for comparison.
Results
A total of 57 patients underwent endoscopic ampullectomy at our institute during this time period. 35 had polyps less than ≤20 mm (smaller polyp group) and 22 had >20 mm polyp size (larger polyp group). Patients with larger polyps were older with a mean age of 69.36 ± 10.1 compared to smaller polyp group with a mean age of 56.43 ± 15.6 (p 0.001). Hot Snare was most employed tool in both groups with occasional use of cold snare in conjunction. Dilute epinephrine and methylene blue solution was used for lifting of the polyp prior to resection in 80 % of the smaller polyp group and 95.5% of the larger polyp group. Pancreatic duct stenting was performed in most cases in both groups and bile duct stenting was pursued in 71.4% of the smaller polyp group and 95.5% of the larger polyp group. Complication rates were similar at 17.1% and 18.2% respectively (p 1.0), with 3 cases each of pancreatitis and bleeding in each group. Pathology confirmed adenoma in 82.9% of the smaller polyp group and 86.4% of the larger polyp group. Recurrence was encountered on subsequent surveillance ERCP exams in 14.3% of patients where the polyp was ≤20 mm and 45.5% when the polyp size was >20 mm (p 0.009). When recurrence was present, it required median 3 (range 2-4) total procedures for eradication. Use of cold snare in addition to hot snare did not lead to significantly higher rate of complications compared to hot snare alone 26.3% versus 13.2% (p 0.19). There was also no significant difference in rate of complications with or without the use of lifting solution prior to polypectomy (p 0.33). Patients in both groups were followed for similar times; mean 23.54 months for smaller polyp group and 27.45 for the larger polyp group (p 0.48).
Conclusion
Polyp size greater than 20 mm appears to have a higher rate of recurrence on subsequent ERCP procedures following initial ampullectomy. Close follow up and detailed examination of the resection site must be pursued on subsequent surveillance procedures following resection of these lesions.