Mutagenicity of bile and duodenal adenomas in familial adenomatous polyposis

Biology of Precancers and Opportunities for Cancer Interception: Lesson from Colorectal Cancer Susceptibility Syndromes

Hereditary gastrointestinal cancer is associated with molecular and neoplastic precursors which have revealed much about sporadic carcinogenesis. Therefore, an appreciation of constitutional and somatic events linked to these syndromes have provided a useful model for the development of risk models and preventative strategies. In this review, we focus of two of the best characterized syndromes, Lynch syndrome (LS) and familial adenomatous polyposis (FAP). Our understanding of the neoplasia-immune interaction in LS has contributed to the development of immune mediated therapies including cancer preventing vaccines and immunotherapy for cancer precursors. Chemoprevention in LS with aspirin and nonsteroidal anti-inflammatory drugs has also translated into clinical cancer, however the efficacy of such agents in FAP remains elusive when cancer is applied as an endpoint in trials rather than the use of 'indirect' endpoints such as polyp burden, and requires further elucidation of biological mechanisms in FAP. Finally, we review controversies in gastrointestinal surveillance for LS and FAP, including limitations and opportunities of upper and lower gastrointestinal endoscopy in the prevention and early detection of cancer.

Endoscopic management of duodenal adenomas in familial adenomatous polyposis--a single-center experience

BACKGROUND

Duodenal lesions (DLS) are common in patients with familial adenomatosis polyposis (FAP), and screening for duodenal adenocarcinoma (DA) is currently recommended. Endoscopic treatment of DLS is controversial.

AIM

To report management and outcomes of endoscopic therapy for DLS in patients with FAP.

METHODS

The records of patients with FAP who underwent endoscopic surveillance or therapy for DLS over a 15-year period were reviewed. Endoscopic intervention included endoscopic surveillance with biopsies, argon plasma coagulation (APC), endoscopic mucosal resection (EMR), EMR with APC, and ampullectomy. Main outcome measurements were recurrence and histology of DLS after endoscopic therapy, complications of endoscopic therapy, and need for duodenectomy.

RESULTS

Seventy-one patients with FAP and DLS were identified from our endoscopy database as undergoing upper endoscopy for screening and/or surveillance (1995-2009). Mean follow up was 4.5 years (1-15 years). Seventy of the seventy-one (98.5%) patients had multiple flat DLS. Most of the patients were followed with yearly biopsies. APC was performed in 17 patients and EMR was performed in eight patients; in five of the eight EMR patients, APC was also performed to treat the edges of EMR site. During the follow up, 17/55 (31%) patients had histological progression (HP). HP was seen in 5/16 (31%) patients who underwent APC (one was lost to follow-up) and 12/40 (30%) patients followed with biopsies alone. Recurrence of lesions was noted in all patients. Two patients underwent duodenectomy. None of the patients developed DA during follow up.

CONCLUSIONS

Endoscopic surveillance with directed endotherapy for DLS in FAP is feasible and safe when diligently performed.

Pancreaticoduodenectomy for advanced duodenal and ampullary adenomatosis in familial adenomatous polyposis

BACKGROUND

Patients with familial adenomatous polyposis (FAP) develop duodenal and ampullary polyps that may progress to malignancy via the adenoma-carcinoma sequence.

OBJECTIVE

The aim of this study was to review a large series of FAP patients undergoing pancreaticoduodenectomy for advanced duodenal and ampullary polyposis.

METHODS

A retrospective case notes review of all FAP patients undergoing pancreaticoduodenectomy for advanced duodenal and ampullary adenomatosis was performed.

RESULTS

Between October 1993 and January 2010, 38 FAP patients underwent pancreaticoduodenectomy for advanced duodenal and ampullary polyps. Complications occurred in 29 patients and perioperative mortality in two. Postoperative histology revealed five patients to have preoperatively undetected cancer (R = 0.518, P < 0.001).

CONCLUSIONS

Pancreaticoduodenectomy in FAP is associated with significant morbidity, but low mortality. All patients under consideration for operative intervention require careful preoperative counselling and optimization.

Familial adenomatous polyposis and the small bowel: a loco-regional review and current management strategies

Small-bowel tumours are an important cause of morbidity and death in patients with familial adenomatous polyposis. Intensive endoscopic surveillance is now standard in the long-term management of this condition. Thus, lesions occurring throughout the small bowel are increasingly noted by oesophagogastroduodenoscopy and flexible pouchoscopy. Some occur commonly de novo (in stomach, duodenum and ampulla), while others may occur following surgery (polyps of the ileostomy, ileoanal pouch, or small bowel above an anastomosis). These differ widely in incidence, natural history and management. This review provides a regional overview of these lesions, in terms of current research findings and management protocols.

Familial adenomatous polyposis predisposes to pathologic exposure of the stomach to bilirubin

BACKGROUND

The role of duodenogastric reflux in the genesis of gastric polyps in familial adenomatous polyposis (FAP), although suggested by scintigraphy scanning studies, remains unclear.

METHODS

Twenty-four hour intragastric bilirubin monitoring with the Bilitec optoelectronic device was carried out in 25 FAP patients, of whom 19 had gastric polyps (fundic gland in 13, adenomatous in 2, and both histologic types in 4) on endoscopic examination. Gastric exposure to bilirubin was expressed as the percentage of total recording time that absorbance exceeded the threshold of 0.25 and was calculated in reference to values obtained from 25 healthy volunteers. Helicobacter pylori status of the stomach was checked as well.

RESULTS

Gastric exposure to bilirubin was pathologic in 14 (56%) patients. Gastric exposure to bilirubin was of longer duration in FAP patients than in healthy volunteers (mean+/-SEM: 19%+/-4% vs 6%+/-2%) (P<.005). It increased from healthy volunteers (6%+/-2%) to FAP patients without gastric polyps (10%+/-3%), and to FAP patients with gastric polyps (22%+/-5%) (P<.004). Bilirubin exposure times were similar in FAP patients with fundic gland polyps only and in those having either adenomatous polyps only or both types of polyps (24%+/-7% vs 17%+/-4%). No patient with pathologic gastric exposure to bilirubin as well as none having gastric polyps, had H. pylori in the antrum.

CONCLUSIONS

This study shows that gastric exposure to bilirubin is of longer duration in FAP patients than in healthy volunteers, and in FAP patients with gastric polyps than in those without polyps. This study supports the existence of a direct correlation between pathologic duodenogastric reflux (DGR), the absence of H. pylori in the antrum, and the presence of gastric polyps in FAP patients.

Frequent somatic mutations of the APC and p53 genes in sporadic ampullary carcinomas

Although a close relation of somatic mutations of the adenomatous polyposis coli gene with ampullary carcinomas in familial adenomatous polyposis patients has been reported, the possible association with sporadic ampullary neoplasms has not been fully examined. We have therefore investigated loss of heterozygosity at the adenomatous polyposis coli locus and the mutational status of a portion of the adenomatous polyposis coli gene, including the mutation cluster region, in 17 ampullary carcinomas of non-familial adenomatous polyposis patients. Alteration of the adenomatous polyposis coli gene was found in 8 of 17 (47.1%) cases, as missense or insertion mutations, with or without loss of heterozygosity. Additional investigation of p53 (exons 5-8) and K-ras (codons 12 and 13) gene mutations revealed a striking mutational pattern of the p53 gene. Nine of the 17 cases demonstrated a total of 12 mutations, 6 clustered at codon 189 and 3 at codon 166. Furthermore, 5 of the 12 mutations were nonsense mutations. Regarding the K-ras gene, 4 of the 17 (23.5%) cases had mutations in codon 12, 3 of the 4 cases being derived from the intraduodenal bile duct. The findings indicate that alterations of the adenomatous polyposis coli and the p53 genes are relatively frequent in sporadic ampullary carcinomas. In particular, the clustering at specific p53 codons might offer an etiological clue to clarify ampullary carcinogenesis. Mutations of the K-ras gene, on the other hand, might be characteristic of intraduodenal bile duct origin.

Familial adenomatous polyposis

Familial adenomatous polyposis (FAP) is an autosomal dominant condition resulting in the development of more than 100 adenomatous polyps in the large bowel. In addition, a number of extracolonic manifestations of the condition may occur. Recently, increasing knowledge relating to the extracolonic abnormalities, and localization and sequencing of the gene for FAP, have had important implications for screening and long-term follow-up of those affected. In this review the natural history of the disease and the extracolonic manifestations associated with it are considered. Surgical management and advances in understanding at a molecular level are discussed, as well as the problems relating to screening for FAP and the implications of the new knowledge.

Mutagenicity of blue rayon extracts of human bile in the Ames test

The mutagenicity of human bile was examined in the Ames Salmonella/microsome assay. Bile samples were obtained from the gallbladders resected from patients with cholelithiasis, choledocholithiasis, gallbladder cancer, extrahepatic bile duct cancer and other diseases. For extraction of mutagenic components, the bile samples were treated with blue rayon and the adsorbed materials were assayed with Salmonella typhimurium TA98 in the presence of S9 mix. Twenty-four bile samples were tested and positive mutagenic activity was found in 14 samples. A 200-microliter bile equivalent material gave 6.3 times as many revertant colonies as the solvent control. With several samples that had undergone two cycles of blue rayon extraction, clear dose-response relationships in mutagenicity were demonstrated.

Cholangiocarcinoma and familial adenomatous polyposis

A case of cholangiocarcinoma occurring in a patient with familial adenomatous polyposis--only the fourth such case reported--is presented. Evidence suggests that tumours of the extrahepatic biliary tree may also be an extra-colonic manifestation of familial adenomatous polyposis.

Gross and histological abnormalities of the foregut in familial adenomatous polyposis: a study from a South East Asian Registry

Polyps in the stomach and duodenum are frequently found in familial adenomatous polyposis. Cancer arising from some of these polyps may be an important cause of death in patients who have had large bowel resections. This study aims to determine the nature and distribution of foregut polyps in Chinese patients. Twenty-five patients with familial adenomatous polyposis were gastroscoped by a single operator using the end viewing video-endoscopy system. Representative biopsies of normal mucosa or polyps where appropriate were taken from the gastric fundus, antrum and the duodenum. Twenty-five patients were studied. Male = 17, female = 8. Median age was 32 years (range = 17-63 yrs). Nineteen patients were found to have macroscopically visible polyps in the foregut. Ten patients had gastric polyps alone, three patients had duodenal polyps alone whilst six patients had both gastric and duodenal polyps. Twelve, one and three patients had more than 20 polyps in the gastric fundus, antrum and duodenum respectively. Only one patient had polyps which were larger than 10 mm. The commonest polyp in the gastric fundus was the fundic gland polyp whilst hyperplastic and adenomatous polyps were the commonest polyps in the gastric antrum and duodenum respectively. Five patients had adenomatous polyps of which four had duodenal adenomas alone whilst one patient had adenomas in the duodenum, gastric antrum and fundus. Seventy-six per cent of our patients with familial adenomatous polyposis had foregut polyposis. Adenomatous polyps were found in 56% of patients with duodenal polyps or 20% of patients with foregut polyps but hyperplastic and hamartomatous polyps occur commonly in patients with familial adenomatous polyposis as well.