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Endoscopic resection techniques

Techniques of endoscopic removal of ampullary adenomas remain unstandardized, likely because of the relatively small number of formal investigations into this practice. Importantly, the term "ampullectomy" refers to removal of the entire ampulla of Vater and is a surgical term for procedures that require surgical reimplantation of the distal common bile duct and pancreatic duct within the duodenal wall. Technically, when endoscopic resections of lesions at the major papilla are performed, only tissue from the papilla can be removed endoscopically, and thus the term "papillectomy" is more appropriate than the term "ampullectomy," although the two are often used interchangeably in the literature.

Submucosal injection.Several authors have advocated the use of submucosal injection immediately before endoscopic papillectomy in a manner similar to that used before performing endoscopic mucosal resection for colorectal polyps. The failure of a lesion to manifest a "lift sign" is associated with malignancy and is considered a contraindication to attempts at complete endoscopic resection (although further endoscopic therapy could be performed as a form of palliation in a poor operative candidate). Fluids injected into the submucosa have included saline solution, epinephrine, methylene blue, and viscous materials such as hydroxypropyl methylcellulose. Volumes of injected fluid are not standardized and vary widely. Some authors have not used submucosal injection, and there are insufficient data to conclude that this is a necessary step in the procedure.

Endoscopic resection

Endoscopic papillectomy is performed by use of endoscopic snares and electrocautery. In most reports standard "braided" polypectomy snares have been used, although fine-wire snares specifically designed for ampullary resection are available. There is no evidence documenting the utility of one type of snare over another. Snare position during papillectomy is also not standardized, with investigators describing successful papillectomy with snares oriented in both a cephalad to caudal orientation and a caudal to cephalad orientation; the majority of published series have not specifically commented on the orientation of the snare during the procedure.

If the lesion can be completely ensnared, en bloc resection with electrocautery can be performed. En bloc resection has the advantages of potentially shortening the procedure time, requiring less electrocautery, and providing a complete tissue sample for pathologic evaluation. Piecemeal resection (with electrocautery) is often performed for lesions larger than 2 cm or in cases where an attempt at en bloc resection has left visible neoplastic tissue in place. Piecemeal resection may produce electrocautery-related injury to tissue fragments sent for pathologic analysis. Piecemeal snare resection may require repeated submucosal injections over time to achieve sustained elevation of the adenomatous tissue. Larger lesions may require multiple endoscopic procedures to be completely removed. Most published series reported using a combination of en bloc and piecemeal resection techniques as the types of lesions treated were of mixed size and architecture.

Electrocautery settings. There is no consensus as to which type of current should be used during endoscopic papillectomy. Both pure cutting current and blended current have been used and neither has been proven to be superior over the other at this time. Power settings are also not standardized.

Pancreatic or biliary sphincterotomy. Given the potential for significant tissue injury to the pancreatic and biliary orifices during endoscopic removal of ampullary adenomas, pancreatic or biliary sphincterotomies are frequently performed during the procedure. Pancreatic or biliary sphincterotomy may assist in providing pancreaticobiliary drainage after papillectomy, simplify attempts to access the common bile duct and pancreatic duct for stent placement, and assist in postprocedure surveillance. There is no consensus as to whether these maneuvers should be performed at all, much less before or after the papillectomy.

Pancreatic or biliary stenting. Endoscopic papillectomy is associated with an increased risk for postproce dural pancreatitis. Several studies have shown that placement of a prophylactic pancreatic duct stent reduces the risk of post-ERCP pancreatitis. It has been implied then that placement of a pancreatic stent during endoscopic papillectomy may also minimize the risk of stenosis of the pancreatic duct orifice and may also allow safer use of adjunctive coagulative therapies, but this theory is unproven. Other authors have suggested that pancreatic duct stents should only be used if pancreatic duct drainage is deemed suboptimal or if the pancreatic duct is difficult to cannulate after the procedure. If a pancreatic duct stent is placed before papillectomy is performed, it may prevent en bloc removal of the lesion, although en bloc resection may make subsequent pancreatic duct stent placement difficult.

The only prospective, randomized, controlled trial to evaluate the role of prophylactic pancreatic duct stenting for the reduction of post-ERCP pancreatitis after endoscopic papillectomy showed a statistically significant decrease in the rate of postprocedure pancreatitis in the stent group. On the basis of these data, prophylactic pancreatic duct stenting during papillectomy is recommended to reduce the risk of postprocedural pancreatitis.

Prophylactic biliary stenting to reduce the risk of postprocedural cholangitis has not been widely performed and cannot be uniformly recommended at this time unless there is concern for inadequate biliary drainage after the papillectomy.

Ablative therapies. Although they are not routinely used as primary therapy for ampullary adenomas, ablative therapies (argon plasma coagulation, laser therapy, monopolar or bipolar electrocoagulation) are useful to destroy residual or recurrent adenomatous tissue not removed during attempts at primary snare resection. Argon plasma coagulation is the most frequently used modality, given its widespread availability and superficial depth of tissue destruction. Unfortunately, tissue treated in this manner is not available for pathologic analysis and any suspicious area should be biopsied before ablation.

Postprocedure evaluation. Endoscopic removal of ampullary adenomas is considered a "high-risk" procedure for complications. A period of postprocedure inpatient observation should be considered for the detection and treatment of any immediate or early delayed complications, especially after extensive removal and treatment of large lesions, in patients with comorbid medical illnesses, those who do not have ready access to medical care, and those without support measures.

Results of endoscopic therapy

Clinical success. Data on the clinical success of endoscopic papillectomy are largely based on retrospective, heterogeneous case series. Successful papillectomy rates range from 46% to 92%, although multiple procedures were often required to completely remove all adenomatous tissue. Larger lesions are more likely to be incompletely excised at the initial endoscopic procedure.

Complications. Early complications after endoscopic papillectomy are similar in nature to other complications of ERCP and include pancreatitis, perforation, bleeding, sedation complications, and cholangitis. Late complications include the development of pancreatic or biliary stenosis. Reported complication rates derived from data from large, tertiary care referral centers and experienced therapeutic endoscopists are as follows: pancreatitis 8% to 15%, perforation 0% to 4%, bleeding 2% to 13%, cholangitis 0% to 2%, and papillary stenosis 0% to 8%. Death after papillectomy is rare but has been reported.

Surveillance for residual or recurrent neoplastic tissue

It is recommended that all patients who have undergone endoscopic papillectomy undergo surveillance endoscopy for the detection of recurrent neoplastic tissue. Reported surveillance intervals have varied but, in general, have included an initial surveillance examination 1 to 6 months after the index procedure followed by repeat examinations with a duodenoscope every 3 to 12 months thereafter for a period of at least 2 years with periodic examinations thereafter. Lesions found to contain areas of high-grade dysplasia may need to be followed more closely. Endpoints for surveillance have not been established. One reasonable approach for sporadic (non-FAP) ampullary polyps is to adopt a surveillance policy similar to that of patients with flat colonic polyps, incorporating degree of dysplasia and evidence of intraductal involvement into the decision-making process.

Role of papillectomy in FAP

The precise role of endoscopic papillectomy in patients with FAP remains unclear because the natural history of the disease and overall outcome in these patients is dependent on the entire duodenal carcinogenic risk rather than that of the ampullary lesion alone. Natural history studies in patients with FAP suggest slow histologic progression of proximal lesions over time and a relatively low risk for development of cancer. Of note, patients who have undergone proctocolectomy are still at high risk for development of ampullary lesions and should undergo periodic surveillance for duodenal and ampullary adenoma and carcinoma.