Familial intestinal polyposis and device assisted enteroscopy: where do we stand?

INTRODUCTION: Hereditary polyposis syndromes are a group of inherited disorders associated with a high risk of developing colorectal cancer. The best known ones are familial adenomatous polyposis (FAP), Peutz-Jeghers (PJS), juvenile polyposis and Cowden syndromes, as well as conditions predisposing to cancer, such as Lynch syndrome. Some of them are characterized by an increased risk of small bowel polyps occurrence. AREAS COVERED: Literature search in PubMed was performed in November 2022 and a narrative review was carried out. Since performing small bowel polypectomy is important in such patients, device assisted enteroscopy (DAE) is the key for this procedure. A screening strategy for small bowel polyps is recommended only for PJS. Guidelines endorse either magnetic resonance imaging (MRI) or videocapsule endoscopy (VCE) every 1-3 years, according to the phenotype of the disease. Enteroscopy should be considered for therapeutic purpose in patients with a positive VCE or MRI. DAE has a central role in the resection of polyps larger than mm or causing symptoms of subocclusion or intussusception. Both single (SBE) and double balloon enteroscopy (DBE) are indicated and able to resect polyps up to 6-10 cm. American guidelines have restricted the indications to small bowel enteroscopy only to FAP patients with grade IV Spiegelman. EXPERT OPINION: Only some groups of patients (PJS, FAP with demonstrated small bowel polyp burden) may benefit from DAE.

Effect of Visual Booklets to Improve Bowel Preparation in Colonoscopy: Systematic Review with Meta-Analysis.

An optimal bowel preparation for colonoscopy is essential to increasing the quality of the examination. Visual booklets have been proposed with conflicting results to enhance bowel preparation. A literature search was performed in March 2023 in the most important databases. Only RCTs were selected. We calculated odd ratios (OR) for dichotomous outcomes. Mean differences (MD) or standardized mean differences (SMD) were used for continuous outcomes. We estimated heterogeneity with the Chi2 and the I2 statistics. In cases of high heterogeneity, a random effect model was used. Six studies were selected, enrolling 1755 patients overall. Adequate bowel preparation was observed in 86.7% of the booklet group versus 77.5% of the control group, with an OR = 2.31 in favor of the booklet. In studies using a 4-L PEG-based preparation, no difference compared to controls was observed, while in non-PEG formulations, preparation with booklets was better than in controls (OR = 5.10, 95% CI 1.82-14.27, p = 0.002). Two studies were performed in an inpatient setting without any differences between booklets and controls, while outpatients receiving booklets had better results (OR = 7.13, 95% CI 5.39-9.45, p < 0.001). The adenoma detection rate was similar between the two groups. In conclusion, booklets are useful to improve bowel preparation. Outpatient settings and preparations not containing PEG could benefit more from booklets.

Molecular Pathways of Carcinogenesis in Familial Adenomatous Polyposis.

Familial adenomatous polyposis (FAP) is a genetic syndrome characterized by the presence of multiple polyps in the gastrointestinal tract and a wide range of systemic extra-intestinal manifestations. Patients affected will inevitably undergo abdominal surgery due to the malignant transformation of one or more adenomas. The pathogenesis of the disease is based on a loss of function mutation in adenomatous polyposis coli (APC), a tumor-suppressor gene, inherited following a Mendelian pattern. This gene is a key component of multiple cell functions that cooperate for homeostasis; when mutated, it contributes to the progression of colorectal adenoma into cancer. Recent studies have demonstrated that several additional mechanisms may influence this process, such as alterations in gut microbiota composition and mucosal barrier immunity, interaction with the immune microenvironment and inflammation, the hormone estrogen, and other signaling pathways. These factors represent promising targets of future therapies and chemoprevention, aiming to alter the progressive nature of the disease and improve the quality of life of families affected. Therefore, we performed a narrative review about the current knowledge of the aforementioned pathways involved in colorectal cancer pathogenesis in FAP, exploring the genetic and environmental factors that may contribute to the development of CRC in FAP.

Serrated Colorectal Lesions: An Up-to-Date Review from Histological Pattern to Molecular Pathogenesis.

Until 2010, colorectal serrated lesions were generally considered as harmless lesions and reported as hyperplastic polyps (HPs) by pathologists and gastroenterologists. However, recent evidence showed that they may bear the potential to develop into colorectal carcinoma (CRC). Therefore, the World Health Organization (WHO) classification has identified four categories of serrated lesions: hyperplastic polyps (HPs), sessile serrated lesions (SSLs), traditional serrated adenoma (TSAs) and unclassified serrated adenomas. SSLs with dysplasia and TSAs are the most common precursors of CRC. CRCs arising from serrated lesions originate via two different molecular pathways, namely sporadic microsatellite instability (MSI) and the CpG island methylator phenotype (CIMP), the latter being considered as the major mechanism that drives the serrated pathway towards CRC. Unlike CRCs arising through the adenoma-carcinoma pathway, APC-inactivating mutations are rarely shown in the serrated neoplasia pathway.

The inulin hydrogen breath test predicts the quality of colonic preparation.

BACKGROUND: Successful bowel preparation is essential to an adequate performance of colonoscopy. Polyethylene glycol (PEG) with electrolyte solutions induces diarrhea with depletion of substrates fermentable by hydrogen (H2)-producing colonic microbiota. Inulin has recently been suggested as a prebiotic substrate for the H2 breath test because it is resistant to intestinal hydrolysis and is fermented mostly by the colonic bacteria. This study aimed to assess time-dependent changes in H2 breath levels in order to predict the colonic preparation of patients scheduled for colonoscopy with or without oral supplementation of inulin. METHODS: In this prospective nonrandomized trial, 127 subjects drank 4 l of PEG 280-mg solution as bowel preparation for colonoscopy. A subgroup of 31 patients also ingested inulin (10 g in 200 ml of water) at breakfast as an additional substrate to increase colonic H2 production. Measurements of H2 breath levels were performed immediately before and after colonic preparation. As the main outcome measure, the quality of the colonic preparation was scored as excellent to fair (i.e., clean bowel allowing successful pan-colonoscopy, including the terminal ileum) or poor (incomplete colonoscopy due to fecal debris). RESULTS: The H2 breath levels decreased from 11.0 ± 1.8 ppm before PEG to 1.8 ± 0.3 ppm after PEG (n = 18; P < 0.001). The H2 concentrations after PEG ingestion were significantly lower (P < 0.001) in the patients with excellent-to-fair preparation than in the 19 patients with poor preparation. Ingestion of inulin induced an overall increase in H2 breath levels and improved discrimination between the patients with excellent-to-fair colonic preparation and those with poor preparation, leading to the sensitivity and specificity of such a test reaching 100 %. CONCLUSIONS: The H2 breath test with inulin ingestion can be a simple, noninvasive, reliable method for predicting successful colonic preparation that leads to cost savings and less patient discomfort/stress or need to repeat colonoscopy.