Management of small bowel and pouch neoplasia in hereditary colorectal cancer syndromes
Introduction
Small bowel and ileal pouch neoplasia represent an often over-looked and under-investigated disease process in patients with familial colorectal cancer (CRC) syndromes. Understandably, the focus when treating these patients is on more common colorectal neoplasia and extra-colonic disease. However, as management of these patients continues to evolve and their survival continues to improve over time, it is possible that small bowel neoplasia will become a more prevalent disease process, especially when a restorative proctocolectomy with ileal pouch anal anastomosis (IPAA) is created. In addition, when patients present with symptoms related to small bowel obstruction or bleeding, vigilance in excluding intrinsic small bowel pathology is required. The aim of this paper is to summarize the incidence and management of small bowel neoplasia in hereditary colorectal syndromes.
Section snippets
Epidemiology
Small bowel adenocarcinoma is rare, even in the context of hereditary cancer syndromes, with an incidence of 2.3 per 100,000 population overall.1, 2 However, the incidence has been rising rapidly based on U.S. SEER (Surveillance, Epidemiology, and End Results Program) data.3 Risk factors include: male sex, age, African American ethnicity, dietary factors, and a personal history of cystic fibrosis, celiac disease, inflammatory bowel disease, prior CRC, or hereditary CRC syndrome.4,5 Typical
Molecular biology
The majority of small bowel adenocarcinomas are thought to arise from neoplastic polyps, but the classical stepwise “adenoma to carcinoma” sequence is less clearly defined than for CRC.9, 10 There is also some evidence that small bowel adenocarcinoma may follow a different genetic pathway than CRC with early abnormal expression of E-cadherin and β-catenin rather than APC.11 This may be due to their recognized relatively rapid development from normal colorectal tissue to cancer over a much
Conclusion
Inherited CRC syndromes require complex screening and active surveillance strategies, and while the CRC risk remains a high priority, the treating physician has the opportunity and responsibility to diligently assess other organ sites for disease development, regardless of rates. While the risk of small bowel neoplasia is typically lower than colorectal neoplasia in patients with hereditary CRC syndromes, these should not be overlooked and remain an important location of potential pathology
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