Subsequent Adenomas of Ileal Pouch and Anorectal Segment After Prophylactic Surgery for Familial Adenomatous Polyposis
Familial adenomatous polyposis (FAP) is an autosomally dominant disease characterized by the early development of colorectal adenomas and carcinoma in untreated patients. Patients with FAP may develop rectal cancer at their initial presentation (primary) or after prophylactic surgery (secondary). Controversies exist regarding which surgical procedure represents the best first-line treatment. The options for FAP are ileorectal anastomosis (IRA) or a restorative proctocolectomy (RPC) with either a handsewn or a stapled ileal pouch-anal anastomosis (IPAA), with or without mucosectomy. The purpose of these surgeries is to stop progression to an adenoma-cancer sequence by eradicating the colon, a disease prone organ. Unfortunately, these surgical procedures, which excise the entire colon and rectum while maintaining transanal fecal continence, do not guarantee that patients still won’t develop adenomas. Based on the available literature, we therefore reviewed reported incidences of pouch-related adenomas that occurred post prophylactic surgery for FAP. The review consists of a collection of case, descriptive, prospective and retrospective reports. Objectives: To provide available data on the natural history of subsequent adenomas after prophylactic surgery (by type) for FAP. Methods: A review was conducted of existing case, descriptive, prospective and retrospective reports for patients undergoing prophylactic surgery for FAP (1975 – August, 2013). In each case, the adenomas were clearly diagnosed in one of the following: the ileal pouch mucosa (above the ileorectal anastomosis), within the anorectal segment (ARS) below the ileorectal anastomosis, or in the afferent ileal loop. Results: A total of 515 (36%) patients with pouch-related adenomas have been reported. Two hundred and eleven (211) patients had adenomas in the ileal pouch mucosa, 295 had them in the ARS and in 9 were in the afferent ileal loop. Patients with pouch adenomas without dysplasia or cancer were either endoscopically polypectomized or were treated with a coagulation modality using either a Nd:Yag laser or argon plasma coagulation (as indicated). Patients with dysplastic pouch adenomas or pouch adenomas with cancer had their pouch excised (pouchectomy). Conclusion: In patients with FAP treated with IRA or RPC with IPAA, the formation of adenomas in the pouch-body mucosa or ARS/anastomosis and in the afferent ileal loop is apparent. Because of risks for adenoma recurrence, a life time endoscopic pouch-surveillance is warranted. Keywords: Familial-adenomatous polyposis, restorative proctocolectomy, ileal-anal pouch anastomosis, ileorectal anastomosis, adenomas.
Amosy E. M'Koma, Alan J. Herline, and Samuel E. Adunyah
"Subsequent Adenomas of Ileal Pouch and Anorectal Segment After Prophylactic Surgery for Familial Adenomatous Polyposis,"
World Journal of Colorectal Surgery:
2, Article 1.
Available at: http://services.bepress.com/wjcs/vol3/iss2/art1
Indications, contraindications, advantages and disadvantages summarized of surgical options for patients with FAP.
Table 2.docx (20 kB)
Summary of published data of the incidence of adenomas after prophylactic surgery for FAP. This table underscores the fact that mucosectomy does not necessarily prevent the development of adenomas in the ATZ
Table 3.docx (14 kB)
Multivariate analysis of risk of adenoma formation in the anorectal segment. Stapled IAA and age at RPC older than 40 years were independent predictors of adenoma formation in ARS. There was no significant association between the APC mutation position or preoperative colonic polyp density and adenoma risk. Adapted with permission: Weston-Petrides et al., (36)
Table 4.docx (12 kB)
Incidence of adenomas (and cancer) in the ATZ in mucosectomized, handsewn IPAA and stapled IPAA in patients with FAP
Figure 1.pdf (61 kB)
Pie chart of histology of visible polyps detected in ileal mucosal at chromoendoscopy in patients with an IPAA (a) or an IRA (b). Abbreviations: LGD=Low grade dysplasia; HGD=High grade dysplasia; LH=Lymphoid (nodular) hyperplasia. Adapted with permission: Moussata et al., (53)
Figure 2.pdf (36 kB)
Cumulative incidence rate of adenomas in the ileal pouch after proctocolectomy with Kock and IPAA (closed diamond) and that of rectal adenomas after colectomy with IRA (open diamond). Adapted with permission: Corfield et al., (56)
Fig. 3.pdf (206 kB)
Spherical sessile adenoma 2 cm in diameter surgically removed from the pouch (A), possessing a lobulated configuration with a smooth surface, broken into lobules by interconnecting clefts (B). Adapted with permission: Tonelli et al., (16).
Fig. 4.pdf (126 kB)
Case 1. A, Macroscopic picture of proctectomy in a 29-year-old man who underwent ileorectal anastomosis 10 years earlier. The mucosa surface was affected by a diffuse polyposis without areas free of neoplastic growth. The mucosectomy specimen is continuous, and the submucosal dissection plane defines the completeness of its removal from the anal transitional zone area. No carcinoma was found in the rectum, but there was 1 adenoma with high-grade dysplasia. B and C, Four years later, the patient underwent pouch excision and definitive ileostomy; the ileal pouch mucosa presented a right lateral elevated mass of 2 cm over a firm basis, located 4 cm from the anal margin and extending cranially for 2 cm. Histological analysis showed an advanced mucinous adenocarcinoma (T3, N0). Adapted with permission: Tonelli et al., (16).