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COMBINED EMR AND EXTENDED LAPAROSCOPIC APPENDECTOMY FOR THE TREATMENT OF CECAL ADENOMAS INVOLVING THE APPENDICEAL ORIFICE: A NOVEL TECHNIQUE
Emily Huang^*1, Ahmed S. Alkoraishi², Craig A. Munroe^3
1Surgery, UCSF, San Francisco, CA; ²Surgery, Kaiser San Francisco, San Francisco, CA; ³Gastroenterology, Kaiser San Francisco, San Francisco, CA

Introduction: Surgical resection is the gold standard in treatment of neoplasia involving the appendiceal orifice (AO). Endoscopic mucosal resection (EMR) of adenomas involving the AO can be challenging for several reasons: 1) resection into the AO carries a risk of appendicitis; 2) the lack of muscularis propria at the os increases the risk of perforation; and 3) it is difficult to guarantee a negative deep margin for polyps growing into the lumen of the appendix. Alternatively, surgical cecectomy for primary resection of AO lesions is limited by the difficulty of ensuring a negative lateral margin without compromising the ileocecal valve; this usually necessitates an ileocecal resection with anastomosis. Although there are reports of EMR for the management of polyps involving the AO, and combined endoscopic and laparoscopic surgery (CELS) has become more widely accepted for a variety of conditions, a structured and combined approach to lesions involving the AO has yet to be described. We describe a novel approach to the treatment of cecal tumors involving the AO—and present an algorithm to guide decision-making regarding when these techniques should be applied.
Methods: All patients referred to our therapeutic endoscopy practice with tumors involving the AO between August 2013 and October 2016 were included. Our approach is outlined in Figure 1: if the lesion involved the AO but did not extend into the os, standard EMR techniques were applied for complete resection (Group 1). Patients with small (≤15mm) lesions extending into the os were referred to a colorectal surgeon for resection via extended laparoscopic appendectomy (ELA, appendectomy with full cecal mobilization to afford a maximal cecal cuff) (Group 2). Patients with large (>15mm) lesions extending into the os underwent EMR resection of the lateral cecal portion of the tumor followed by ELA for the appendiceal margin in either a one- or two-stage intervention (Group 3).
Results: 32 patients were included in the study; 12 patients in Group 1 underwent EMR only, 11 patients in Group 2 underwent ELA only, and 9 patients in Group 3 underwent a combined resection. The only complications were post-polypectomy syndrome in two patients undergoing EMR. One EMR-only patient with a positive lateral margin was referred for appendectomy, but declined. No patient required ileocecectomy. Examination of the pathology reveals a high rate of SSA (34%), as noted in other literature on appendiceal polyps (Table 1).
Conclusion: Our results introduce a decision algorithm and suggest that EMR combined with ELA is a safe, curative, and potentially superior technique for treatment of large cecal adenomas involving the AO. Future investigation will examine recurrence rates on follow-up, but these are not expected to differ from the typical rate for EMR in experienced hands.

Characteristics of cecal adenomas involving the appendiceal orifice, by study group

AO involvement and adenoma site	Paris Classification				Pathology
	Isp	Is	IIa	IIb	TA	TVA	VA	SSA	IC
No AO involvement (Group 1; N=12)	1	1	10		6	1		5
AO involved; lesion up to 15mm (Group 2; N=11)	1	1	5	2	5			6
AO involved; lesion >15mm (Group 3; N=9)	2		4	3	4	3	1		1

TA = tubular adenoma
TVA = tubulovillous adenoma
VA = villous adenoma
SSA = sessile serated adenoma
IC = intramucosal carcinoma

Figure 1: Decision algorithm for the use of EMR and extended laparoscopic appendectomy in treating cecal adenomas involving the appendiceal orifice

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