Cancer in Crohn's disease: dispelling the myths

The Complex Network between Inflammation and Colorectal Cancer: A Systematic Review of the Literature

Simple Summary

Colorectal cancer is one of the most diffuse malignant pathologies, and many factors are involved in its genesis. Among these factors, inflammation plays an important role. Many molecules are involved in inflammation processes and are linked in different pathways, either in the sense of pro-tumorigenesis or anti-tumorigenic action. This review was conducted with the aim to review in a single paper the majority of actual knowledge in the literature and to comprehend inflammation patterns for better clinical and surgical management of patients.

Abstract

Background: colorectal cancer (CRC) has a multifactorial etiology which comprises microbiota, genetic predisposition, diet, environmental factors, and last but not least, a substantial contribution by inflammation. The aim of this study is to conduct a systematic review of the literature regarding the strong link between inflammation and colorectal cancer. Methods: A systematic review of the literature on PubMed (Medline), Scopus, Cochrane and EMBase databases was performed, following the PRISMA 2020 guidelines. Each paper was reviewed by two groups of researchers in a single-blind format by using a pre-planned Microsoft^© Excel^® grid. Results: Using automated research filters, 14,566 studies were included, but 1% was found significant by the reviewers. Seventy pathways of inflammation were described in the sequence of inflammation-carcinogenesis, and anti-tumorigenic molecules were also found. Conclusion: several studies suggest a strong role of inflammation in the tumorigenesis of colorectal cancer through different pathways: this may have a diagnostic and clinical role and also therapeutic purpose in preventing carcinogenesis by treating inflammation. In vitro tests support this theory, even if many other clinical trials are necessary. The present paper was registered in the OpenScience Framework registry (Identifier: DOI 10.17605/OSF.IO/2KG7T).

Gastrointestinal Pathobionts in Pediatric Crohn's Disease Patients

Crohn's disease (CD) is an inflammatory disease of the gastrointestinal tract, with a rising incidence worldwide, particularly in children. CD is thought to arise due to an immune response to environmental factors. The role of bacteria in CD has recently been highlighted, and here, we examine the prevalence of two bacterial species, enterotoxigenic Bacteroides fragilis (ETBF) and Fusobacterium nucleatum, implicated in gastrointestinal pathologies, in a pediatric CD cohort. Stool samples from 30 children with treatment-naïve CD and 30 age- and sex-matched controls were collected, and DNA was extracted. Quantitative PCR was used to determine the levels of ETBF and F. nucleatum in stool samples. Bacterial positivity and relative abundance were assessed between cases and controls and in relation to disease severity. No associations were found between colonization with ETBF and CD, or between colonization with either ETBF or F. nucleatum and disease severity or presence of C. concisus. However, a strong association was observed between positivity for F. nucleatum in the stool samples and the occurrence of CD in patients (25/30) as compared to controls (8/30) (P=0.003). F. nucleatum is more prevalent in the stool samples of pediatric CD patients, compared to healthy controls, and may have potential use as a biomarker of pediatric CD.

Establishment and characterization of HROC69 - a Crohn´s related colonic carcinoma cell line and its matched patient-derived xenograft

Colitis-associated colorectal cancer (CAC) seems to be a rather unique entity and differs in its genetic alterations, tumour formation capacities, and clinical features from sporadic colorectal carcinoma. Most descriptions about tumour biology of CAC refer to ulcerative colitis; data about Crohn´s colitis related carcinomas are scarce. The majority of patients with Crohn´s disease are under immunosuppression which generates a different environment for tumour growth. We first describe the clinical case of a fast growing CAC in a long-term immunosuppressed patient with Crohn´s disease and successful establishment and characterization of carcinoma cell lines along with their corresponding patient-derived xenograft. Subsequently, these tumor models were molecularly and functionally analysed. Beside numerous chromosomal alterations, mutations in TP53, APC, PTEN and SMAD3 were identified. The cell lines express numerous cancer testis antigens, surface molecules involved in immune evasion but low levels of HLA class I molecules. They show strong invasive but in comparison weak migratory activity. The present work is the first description of patient-derived in vitro and in vivo models for CAC from a Crohn´s disease patient. They might be valuable tools for analysis of genetic and epigenetic alterations, biomarker identification, functional testing, including response prediction, and the development of specific therapeutical strategies.

Calpain-2 Inhibitor Therapy Reduces Murine Colitis and Colitis-associated Cancer

BACKGROUND

An important role has emerged for calpain enzymes in regulating inflammation with one isoform, calpain-2, particularly important for macrophage activation. The goal of this study was to determine the therapeutic potential of a synthetic calpain-2 inhibitor, zLLY-CH2F, for colitis and inflammation-associated colorectal cancer.

METHODS

Mice were then subjected to the azoxymethane/dextran sulfate sodium model of colitis and colitis-associated cancer incorporating intervention with daily injections of 0.75 mg/kg calpain-2 inhibitor beginning after the first signs of colitis.

RESULTS

Calpain-2 inhibitor treatment alleviated weight loss and bloody diarrhea, and reduced inflammatory infiltration into colon tissues and inflammatory cytokine mRNA. Calpain-2 inhibitor intervention also reduced total colitis-associated cancer tumor volume by up to 70% in vehicle control mice and decreased cancer pathology scores of blinded histological colon tissue analyses. Mechanistic investigations showed that calpain-2 inhibition during macrophage activation reduced inhibitor of kappa beta (IκB) degradation and nuclear factor kappa beta (NFκB) nuclear localization as well as secretion of specific inflammatory cytokines. In addition, calpain-2 inhibitor treatment of CT26.WT mouse and HT-29 human colorectal cancer cells decreased proliferation and reduced IκB degradation and NFκB translocation.

CONCLUSIONS

Overall, these findings suggest that intervention with a calpain-2 inhibitor may reduce colitis and colitis-associated cancer through a two-hit process of limiting macrophage activation and inhibiting growth of the colorectal cancer cells themselves.

Molecular Alterations of Colorectal Cancer with Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is an important etiologic factor in the development of colorectal cancer (CRC). The risk of CRC begins to increase 8 or 10 years after the diagnosis of IBD. This type of cancer is called colitis-associated CRC (CA-CRC). The molecular pathogenesis of inflammatory epithelium might play a critical role in the development of CA-CRC. Genetic alterations detected in CA-CRC such as genetic mutations, microsatellite instability, and DNA hypermethylation are also recognized in sporadic CRC; however, there are differences in the timing and frequency of molecular events between CA-CRC and sporadic CRC. Interaction between gene-environmental factors, including inflammation, lifestyle, psychological stress, and prior appendectomy, might be associated with the etiopathology of IBD. The mucosal inflammatory mediators, such as oxidant stress, free radicals, and chemokines, may cause the genetic alterations. Understanding the molecular mechanisms of CA-CRC might be important to develop clinical efficacies for patients with IBD. This review discusses the molecular characteristics of CA-CRC, especially ulcerative colitis-associated CRC, including clinical features, signaling pathways, and interactions between genetic alterations and environment involved in inflammatory carcinogenesis.

Outcome of "indefinite for dysplasia" in inflammatory bowel disease: correlation with DNA flow cytometry and other risk factors of colorectal cancer

Dysplasia that develops in the setting of inflammatory bowel disease precedes colorectal cancer (CRC). The category of "indefinite for dysplasia (IND)" is used often in equivocal cases, but its clinical significance remains unclear. Flow cytometric analysis of DNA content (aneuploidy) has shown some promise in stratifying patients into low or high risk of CRC, but there are few reports that have specifically evaluated the outcome of IND. As such, we analyzed a series of 84 IND inflammatory bowel disease patients seen at the University of Washington and Harborview Medical Centers from 2003 to 2013 to determine the outcome of IND. Hospital electronic medical records were further reviewed to correlate outcome with the type of lesion (flat versus polypoid), primary sclerosing cholangitis, active inflammation in the area of IND, and DNA flow cytometric data. The data show that 13% of IND cases were found to have low-grade dysplasia, whereas only 2% of IND cases showed advanced neoplasia (high-grade dysplasia or CRC) after a mean follow-up of 28 months. The risk of neoplasia was not significantly associated with the type of lesion (P = .94 from log-rank test), primary sclerosing cholangitis (P = .94), or active inflammation (P = .41) in this cohort. However, the finding of DNA aneuploidy at baseline IND was predictive of subsequent detection of neoplasia (P = .037). IND patients with abnormal DNA flow cytometric results may warrant more careful follow-up, but conversely, IND in the setting of normal DNA content may require less frequent surveillance colonoscopy.

Inflammatory bowel disease cause-specific mortality: a primer for clinicians

BACKGROUND

Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC) is perceived to harbor significant morbidity but limited excess mortality, thought to be driven by colon cancer, compared with the general population. Recent studies suggest mortality rates seem higher than previously understood, and there are emerging threats to mortality. Clinicians must be up to date and able to clearly convey the causes of mortality to arm individual patients with information to meaningfully participate in decisions regarding IBD treatment and maintenance of health.

METHODS

A MEDLINE search was conducted to capture all relevant articles. Keyword search included: "inflammatory bowel disease," "Crohn's disease," "ulcerative colitis," and "mortality."

RESULTS

CD and UC have slightly different causes of mortality; however, malignancy and colorectal cancer-associated mortality remains controversial in IBD. CD mortality seems to be driven by gastrointestinal disease, infection, and respiratory diseases. UC mortality was primarily attributable to gastrointestinal disease and infection. Clostridium difficile infection is an emerging cause of mortality in IBD. UC and CD patients have a marked increase in risk of thromboembolic disease. With advances in medical and surgical interventions, the exploration of treatment-associated mortality must continue to be evaluated.

CONCLUSIONS

Clinicians should be aware that conventional causes of death such as malignancy do not seem to be as significant a burden as originally perceived. However, emerging threats such as infection including C. difficile are noteworthy. Although CD and UC share similar causes of death, there seems to be some differences in cause-specific mortality.

Ulcerative colitis-associated colorectal cancer

The association between ulcerative colitis (UC) and colorectal cancer (CRC) has been acknowledged. One of the most serious and life threatening consequences of UC is the development of CRC (UC-CRC). UC-CRC patients are younger, more frequently have multiple cancerous lesions, and histologically show mucinous or signet ring cell carcinomas. The risk of CRC begins to increase 8 or 10 years after the diagnosis of UC. Risk factors for CRC with UC patients include young age at diagnosis, longer duration, greater anatomical extent of colonic involvement, the degree of inflammation, family history of CRC, and presence of primary sclerosing cholangitis. CRC on the ground of UC develop from non-dysplastic mucosa to indefinite dysplasia, low-grade dysplasia, high-grade dysplasia and finally to invasive adenocarcinoma. Colonoscopy surveillance programs are recommended to reduce the risk of CRC and mortality in UC. Genetic alterations might play a role in the development of UC-CRC. 5-aminosalicylates might represent a favorable therapeutic option for chemoprevention of CRC.

Distribution of bone-marrow-derived endothelial and immune cells in a murine colitis-associated colorectal cancer model

Inflammatory bowel disease (IBD) can lead to an increased risk of developing colorectal cancer (CRC). The aim of this study was to establish a model for combined bone marrow transplantation (BMT) and colitis-associated colorectal cancer (CAC) and to define the contribution of BM-derived cells during the inflammation associated with carcinogenesis. We established a model for BMT using green fluorescent protein (GFP) transgenic mice, followed by AOM/DSS-induced CAC, and performed confocal microscopy analysis on in vivo living tissue and frozen tumor sections. Our imaging analyses showed that GFP-positive cells extensively infiltrated the tumor stroma and that some WGA and GFP or CD31 and GFP double-positive cells were observed in the lining of tumor vessels. Flow cytometry analysis of the tumor-infiltrating cells showed that the GFP-positive CD11c+ DCs cells were one-third of the GFP+/CD11C- cells, and that half of these DCs (0.96% vs 1.02%) were GFP-positive BM-derived cells. The majority of CD4⁺ T cells were GFP-negative (12.02% vs 1.9%), and we discovered a novel CD4⁺ CD11c⁺ DC subset (0.34% vs 1.64%). In conclusion, we defined the distribution of BM-derived endothelial cells, CD11c⁺ DCs and CD4⁺ T cells in tumors. This model might be useful for elucidating the diverse BM-derived cell types and functions during the progression of colitis-associated colorectal cancer.

High rates of metachronous colon cancer or dysplasia after segmental resection or subtotal colectomy in Crohn's colitis

BACKGROUND

In ulcerative colitis, total proctocolectomy is the treatment of choice for patients with colonic dysplasia or cancer because of the high risk for metachronous neoplasia. It is unknown whether patients with Crohn's disease and colon cancer or dysplasia have a similar risk.

METHODS

We retrospectively reviewed the charts of 75 patients treated at our center from 2001 to 2011 with Crohn's disease and colon cancer who underwent segmental resection or subtotal colectomy (STC). We then identified the presence or absence of subsequent colon cancer or dysplasia in these patients during the follow-up (0-19 years).

RESULTS

Of the 64 patients with colon cancer, 25 had at least 1 metachronous cancer (39%). The mean time to a new cancer was 6.8 years. Eighty-five percent of patients (21/25) were undergoing annual screening colonoscopy. Of the 11 patients with dysplasia, 5 (46%) had a new dysplasia. Mean time to a new dysplastic lesion was 5.0 years. Nineteen of the 47 patients (40%) who had a segmental resection for colon cancer developed metachronous cancer and 6/17 patients (35%) with a STC had metachronous cancer. Two of the 4 patients (50%) with STC for dysplasia (50%) had a new dysplasia and 3/7 patients (43%) with segmental resection had a new dysplasia. There was no significant difference (P = 0.61) between recurrence rates in patients with segmental resection versus STC.

CONCLUSIONS

The high rate of metachronous colon cancer after surgical resection suggests that total proctocolectomy should be considered. Larger studies are required to determine if the same is true for dysplasia.

Contrast-enhanced MR enterography as a stand-alone tool to evaluate Crohn's disease in a paediatric population

AIM

To assess the performance of contrast-enhanced T1-weighted magnetic resonance imaging (MRI) alone in the evaluation of Crohn's disease in comparison to all magnetic resonance enterography (MRE) imaging sequences together in an attempt to suggest limitation of the number of overall unenhanced sequences need for the follow-up evaluation.

MATERIALS AND METHODS

Twenty-five paediatric patients (mean age 14.1 ± 3.7 years, male = 12, female = 13) underwent MRE at 1.5 T for evaluation of Crohn's disease. Two radiologists reviewed only contrast-enhanced T1-weighted images in consensus on the first session. Whole images including unenhanced (steady-state free precession, single-shot fast spin-echo (HASTE), fat-suppressed T2-weighted) and contrast-enhanced T1-weighted sequences were reviewed in consensus during the second session with a 1 month interval, which was used as a reference standard. The readers evaluated the presence or absence of disease in 10 bowel segments in each patient. For the abnormal bowel segments, the readers then evaluated for active versus inactive disease and for the presence or absence of abscess. Sensitivity, specificity, and overall accuracy were calculated for detecting active inflammation.

RESULTS

There were 53/250 bowel segments with active inflammation using the reference standard imaging method. The sensitivity, specificity, and accuracy for diagnosing active inflammation using contrast-enhanced images alone were 83.3%, 86.9%, and 84.9%. In five of the false-positive cases of detecting abscess from contrast-enhanced imaging alone, absence of abscesses was confirmed on the non-fat-suppressed HASTE images.

CONCLUSION

The number of MRE sequences in paediatric Crohn's patients can be decreased while maintaining diagnostic accuracy using contrast-enhanced T1 and non-fat-suppressed HASTE images.

Histopathology analysis of benign colorectal diseases and colorectal cancer in Hatyai Hospital, Songkhla, Thailand

BACKGROUND

Colorectal cancer (CRC) is a major cause of morbidity and mortality in the western world and also ranks as the fifth-leading malignancy and death in Thailand. This study aimed to provide a present outlook of colorectal diseases among Thai patients with special emphasis on CRC in Hatyai, Songkhla, southern Thailand.

MATERIALS AND METHODS

This retrospective study covered ten year data of CRC, benign colorectal tumors and non-colorectal tumors from the Department of Pathology in Hatyai Hospital, Songkhla, Thailand, between years 2003-2012. Incidence rates based on age, gender, ten year incidence trends, and distribution of histopathological characteristics of patients were calculated and demonstrated.

RESULTS

Out of 730 biopsies, 100 cases were benign colorectal tumors, 336 were CRC and 294 were non-colorectal tumors. Colorectal tumors (both benign and CRC) (60.1%) were more common than non-colorectal tumors (39.9%). CRC (77.1%) were more common than benign colorectal tumors (32.9%). Colorectal tumors were mainly found in patients aged over sixty whereas non-colorectal and benign colorectal tumors were found in those under sixty (P=0.01). sAmong CRC, adenocarcinoma contributed about 97.3% of all cases with well differentiated tumors being the most frequent (56.9%). Both benign colorectal tumors and CRC were more commonly found in males (63%) than females (37%). The incidence trend of CRC demonstrated increase from 2003-2012.

CONCLUSIONS

The incidence of CRC increased in Hatyai from 2003-2012. CRC tends to be more common in people older than sixty, thus, screening programs, cost-effective analysis of treatment modalities, and treatment protocols for the elderly should be examined. Proper implementation of preventive measures such as changing lifestyle factors might enhance control of colorectal disease.

Potential avenues for immunotherapy of colitis-associated neoplasia

In patients with inflammatory bowel disease, chronic intestinal inflammation severely increases the risk for cancer development. In fact, various aspects of inflammation such as oxidative stress, cyclooxygenases and proinflammatory cytokines have been shown to support many aspects of cancer growth. During recent years, various experimental studies have increased our understanding of the molecular mechanisms leading to colitis-associated cancer. In particular, cytokines such as TNF-α or IL-6, which are involved in the pathogenesis of inflammation and cancer development, could be promising targets for the molecular prevention of colitis-associated cancer.

Endoscopic assessment of inflammatory bowel disease: colonoscopy/esophagogastroduodenoscopy

Endoscopy plays an important role in the initial diagnosis of IBD, including the evaluation of disease severity, activity, and extent. The implications of complete mucosal healing further confirm the function of endoscopy in the follow-up of IBD patients. The use of therapeutic endoscopy, for example stricture dilatation, can avoid the need for bowel resection. Modalities such as capsule endoscopy, EUS, NBI, CE, and other emerging techniques are likely to have an increasing role in the management of IBD, particularly in the area of dysplasia surveillance and treatment.

Dysplasia and cancer in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic gastrointestinal disease associated with an increased risk of colorectal cancer (CRC). Although CRC occurs in a minority of IBD patients (1%), it carries a high mortality and accounts for 20% of IBD-related mortality. Established risk factors for the development of CRC in IBD include disease duration of 8 years or more, family history of CRC, extensive colitis and primary sclerosing cholangitis. Meticulous colonoscopy and anti-inflammatory medications can reduce the risk of developing CRC. The future of IBD surveillance involves the use of novel endoscopic techniques (chromoendoscopy, narrow-band imaging, confocal laser endomicroscopy and autofluorescence) to enhance colonoscopic accuracy, in concert with chemopreventative medications to help reduce the risk of CRC in IBD.

Does the prognosis of colorectal cancer vary with tumor site?

AIM

The aim of this study was to compare prognostic factors between colon and rectal cancers.

BACKGROUND

Prognosis of Colorectal Cancer (CRC) may depend on the anatomical site.

PATIENTS AND METHODS

A total of 1219 patients with CRC diagnosis according to the pathology report of RCGLD cancer registry, from 1 January 2002 to 1 October 2007, were entered into the study. Demographic and clinico-pathological factors were analyzed using survival analysis.

RESULTS

From age at diagnosis, colon cancer had significantly better survival than rectal cancer (Multivariate Hazard Ratio (MVHR)=0.24; 95% Confidence Interval (CI) =(0.074-0.77)). Other factors, including marital status (MVHR =1.78; 95% CI =(0.33-9.62)), body mass index (BMI) (MVHR =1.21 and 1.54; 95% CI =(.30-4.85) and (.44-5.4) respectively for < 18.5 and >30 BMI groups), pathologic stage (MVHR =.64; 95% CI =(.21-1.98)) and alcohol history (MVHR =4.86; 95% CI =(.67-35.14)) were not significantly different between the two patient group but suggested a possible effect upon prognosis. Overall survival in rectum was better than that of colon.

CONCLUSION

Our findings support this hypothesis that prognosis of CRC varies with tumor site.

Mechanisms by which inflammation may increase intestinal cancer risk in inflammatory bowel disease

Patients with ulcerative colitis and Crohn's disease are at increased risk of developing intestinal cancers via mechanisms that remain incompletely understood. However, chronic inflammation and repeated events of inflammatory relapse in inflammatory bowel disease (IBD) expose these patients to a number of signals known to have tumorigenic effects including persistent activation of the nuclear factor-kappaB and cyclooxygenase-2/prostaglandin pathways, release of proinflammatory mediators such as tumor necrosis factor-alpha and interleukin-6, and enhanced local levels of reactive oxygen and nitrogen species. These inflammatory signals can contribute to carcinogenesis via 3 major processes: 1) by increasing oxidative stress, which promotes DNA mutagenesis thus contributing to tumor initiation; 2) by activating prosurvival and antiapoptotic pathways in epithelial cells, thereby contributing to tumor promotion; and 3) by creating an environment that supports sustained growth, angiogenesis, migration, and invasion of tumor cells, thus supporting tumor progression and metastasis. The present review integrates clinical and basic research observations in an attempt to provide a comprehensive understanding of how inflammatory processes may contribute to intestinal cancer development in IBD patients.

Perforin deficiency attenuates inflammation and tumor growth in colitis-associated cancer

BACKGROUND

Patients with inflammatory bowel disease (IBD) have a markedly increased risk to develop colon cancer, but there are only limited data about the host antitumor response in such colitis-associated cancer. In the present study we aimed at assessing the role of perforin-dependent effector mechanisms in the immune response in a murine model of colitis-associated colon cancer.

METHODS

Wildtype and perforin-deficient mice were analyzed in a mouse model of colitis-associated colon cancer using azoxymethane (AOM) and dextran sodium sulfate (DSS).

RESULTS

Tumors of wildtype mice showed infiltration of CD4+, CD8+ T cells, natural killer (NK) cells, high numbers of apoptotic cells, and expression of the transcription factor eomesodermin and cytotoxic effector proteins, suggesting a potential role of the antitumor immune response in AOM/DSS tumorigenesis. Furthermore, perforin deficiency resulted in reduced apoptosis of epithelial cells as compared to wildtype mice, whereas tumor infiltration by NK cells, CD8+, and CD4+ T cells was unchanged. However, perforin-deficient mice surprisingly developed significantly fewer tumors than wildtype mice. Subsequent studies identified an important role of perforin in regulating colitis activity, as perforin deficiency caused a significant reduction of DSS colitis activity and proinflammatory cytokine production as compared to wildtype controls.

CONCLUSIONS

Perforin is involved in both the antitumor immune response and the regulation of activity of mucosal inflammation in colitis-associated cancer. Our data emphasize the possible consequences for therapeutic strategies targeting colitis-associated colon cancer.

Potential role of chitinase 3-like-1 in inflammation-associated carcinogenic changes of epithelial cells

The family of mammalian chitinases includes members both with and without glycohydrolase enzymatic activity against chitin, a polymer of N-acetylglucosamine. Chitin is the structural component of fungi, crustaceans, insects and parasitic nematodes, but is completely absent in mammals. Exposure to antigens containing chitin- or chitin-like structures sometimes induces strong T helper type-I responses in mammals, which may be associated with the induction of mammalian chitinases. Chitinase 3-like-1 (CHI3L1), a member of the mammalian chitinase family, is induced specifically during the course of inflammation in such disorders as inflammatory bowel disease, hepatitis and asthma. In addition, CHI3L1 is expressed and secreted by several types of solid tumors including glioblastoma, colon cancer, breast cancer and malignant melanoma. Although the exact function of CHI3L1 in inflammation and cancer is still largely unknown, CHI3L1 plays a pivotal role in exacerbating the inflammatory processes and in promoting angiogenesis and remodeling of the extracellular matrix. CHI3L1 may be highly involved in the chronic engagement of inflammation which potentiates development of epithelial tumorigenesis presumably by activating the mitogen-activated protein kinase and the protein kinase B signaling pathways. Anti-CHI3L1 antibodies or pan-chitinase inhibitors may have the potential to suppress CHI3L1-mediated chronic inflammation and the subsequent carcinogenic change in epithelial cells.

Inflammation and colorectal cancer

Patients with long-standing inflammatory bowel disease (IBD) have an increased risk of developing colorectal cancer (CRC). However, the underlying mechanisms are not entirely clear. A genetic basis for the increased risk of CRC in IBD patients is only a partial explanation. It is possible that high levels of inflammatory mediators that are produced in this setting may contribute to the development and progression of CRC. Growing evidence supports a role for various cytokines, released by epithelial and immune cells, in the pathogenesis of IBD-associated neoplasia. Two key genes in the inflammatory process, cyclooxygenase-2 (COX-2) and nuclear factor kappaB (NF-kappaB), provide a mechanistic link between inflammation and cancer while other factors such as, TNF-alpha and IL-6-induced signaling have been recently shown to promote tumor growth in experimental models of colitis-associated cancer. This article reviews the pathogenesis of IBD-related CRC and summarizes the molecular mechanisms underlying the development of intestinal neoplasia in the setting of chronic inflammation.

Diagnosis and management of dysplasia in patients with ulcerative colitis and Crohn's disease of the colon

To minimize the possibility of developing lethal colorectal cancer (CRC) in ulcerative colitis (UC) and Crohn's colitis, patients are usually enrolled in a program of dysplasia surveillance. The success of a surveillance program depends on the identification of patients with dysplasia and timely referral for colectomy. While a number of issues might stand in the way of a surveillance system achieving its maximal effect (less than ideal agreement in the interpretation of biopsy specimens, sampling error by endoscopists, delays in referral to surgery, and patient drop-out among others), circumstantial evidence supports the concept that colonoscopic dysplasia surveillance is an effective means of reducing CRC mortality and morbidity while minimizing the application of colectomy for cancer prevention. This review critically appraises key issues in the diagnosis and management of dysplasia in UC and Crohn's disease as well as adjunct efforts to prevent CRC in inflammatory bowel disease.

Asymptomatic ileal adenocarcinoma in the setting of undiagnosed Crohn’s disease

A 53-year old previously healthy male underwent a screening colonoscopy for detection of a potential colorectal neoplasm. The terminal ileum was intubated and a mass was noted. Examination of the colon was normal. The biopsy of the ileal mass was consistent with an adenocarcinoma arising from the terminal ileum. His father who had never been previously ill from gastrointestinal disease died of natural causes, but was found to have Crohn’s disease postmortem. The patient underwent exploratory laparotomy and a right hemicolectomy with a 30 cm section of terminal ileum in continuity. Findings were consistent with ileal adenocarcinoma in the setting of Crohn’s disease. The patient made an uneventful recovery. The pathology was stage 1 adenocarcinoma. This is a unique case in that on a screening colonoscopy, a favorable ileal adenocarcinoma was discovered in the setting of asymptomatic, undiagnosed ileal Crohn’s disease in a patient whose father had Crohn’s disease diagnosed postmortem.

Cancer in inflammatory bowel disease

Patients with long-standing inflammatory bowel disease (IBD) have an increased risk of developing colorectal cancer (CRC). Many of the molecular alterations responsible for sporadic colorectal cancer, namely chromosomal instability, microsatellite instability, and hypermethylation, also play a role in colitis-associated colon carcinogenesis. Colon cancer risk in inflammatory bowel disease increases with longer duration of colitis, greater anatomic extent of colitis, the presence of primary sclerosing cholangitis, family history of CRC and degree of inflammation of the bowel. Chemoprevention includes aminosalicylates, ursodeoxycholic acid, and possibly folic acid and statins. To reduce CRC mortality in IBD, colonoscopic surveillance with random biopsies remains the major way to detect early mucosal dysplasia. When dysplasia is confirmed, proctocolectomy is considered for these patients. Patients with small intestinal Crohn's disease are at increased risk of small bowel adenocarcinoma. Ulcerative colitis patients with total proctocolectomy and ileal pouch anal-anastomosis have a rather low risk of dysplasia in the ileal pouch, but the anal transition zone should be monitored periodically. Other extra intestinal cancers, such as hepatobiliary and hematopoietic cancer, have shown variable incidence rates. New endoscopic and molecular screening approaches may further refine our current surveillance guidelines and our understanding of the natural history of dysplasia.

p53 mutations are associated with dysplasia and progression of dysplasia in patients with Crohn's disease

BACKGROUND

Mutations in the tumor suppressor gene p53 are associated with neoplasia in ulcerative colitis, but little is understood of their significance in Crohn's disease (CD).

PURPOSE

To explore p53 expression as a marker of neoplasia in CD patients.

METHODS

This is a retrospective review of CD patients who underwent p53 IHC staining in our center between 1995 and 2003. The p53 status was correlated to the presence and grade of neoplasia at the time of staining and in subsequent follow-up.

RESULTS

Fourteen CD patients had p53 assessment: eight were p53 positive and six were p53 negative. Seven of eight p53+ had dysplasia (six LGD, one HGD); one of six p53-had dysplasia (LGD) (P = 0.03). Four p53+ patients with follow-up had persistent dysplasia and two had progression to a higher grade. Three p53- patients with follow-up remained free of dysplasia.

CONCLUSIONS

This limited study shows that p53 over expression in CD patients is associated with dysplasia that may progress to a higher grade of neoplasia over time.

Cancer in inflammatory bowel disease

Patients with long-standing inflammatory bowel disease (IBD) have an increased risk of developing colorectal cancer (CRC). Many of the molecular alterations responsible for sporadic colorectal cancer, namely chromosomal instability, microsatellite instability, and hypermethylation, also play a role in colitis-associated colon carcinogenesis. Colon cancer risk in inflammatory bowel disease increases with longer duration of colitis, greater anatomic extent of colitis, the presence of primary sclerosing cholangitis, family history of CRC and degree of inflammation of the bowel. Chemoprevention includes aminosalicylates, ursodeoxycholic acid, and possibly folic acid and statins. To reduce CRC mortality in IBD, colonoscopic surveillance with random biopsies remains the major way to detect early mucosal dysplasia. When dysplasia is confirmed, proctocolectomy is considered for these patients. Patients with small intestinal Crohn’s disease are at increased risk of small bowel adenocarcinoma. Ulcerative colitis patients with total proctocolectomy and ileal pouch anal-anastomosis have a rather low risk of dysplasia in the ileal pouch, but the anal transition zone should be monitored periodically. Other extra intestinal cancers, such as hepatobiliary and hematopoietic cancer, have shown variable incidence rates. New endoscopic and molecular screening approaches may further refine our current surveillance guidelines and our understanding of the natural history of dysplasia.

The risk of cancer in patients with Crohn's disease

PURPOSE

The risk of cancer in patients with Crohn's disease is not well defined. Using meta-analytical techniques, the present study was designed to quantify the risk of intestinal, extraintestinal, and hemopoietic malignancies in such patients.

METHODS

A literature search identified 34 studies of 60,122 patients with Crohn's disease. The incidence and relative risk of cancer were calculated for patients with Crohn's disease and compared with the baseline population of patients without Crohn's disease. Overall pooled estimates, with 95 percent confidence intervals, were obtained, using a random-effects model.

RESULTS

The relative risk of small bowel, colorectal, extraintestinal cancer, and lymphoma compared with the baseline population was 28.4 (95 percent confidence interval, 14.46-55.66), 2.4 (95 percent confidence interval, 1.56-4.36), 1.27 (95 percent confidence interval, 1.1-1.47), and 1.42 (95 percent confidence interval, 1.16-1.73), respectively. On subgroup analysis, patients with Crohn's disease had an increased risk of colon cancer (relative risk, 2.59; 95 percent confidence interval, 1.54-4.36) but not of rectal cancer (relative risk, 1.46; 95 percent confidence interval, 0.8-2.55). There was significant association between the anatomic location of the diseased bowel and the risk of cancer in that segment. The risk of small bowel cancer and colorectal cancer was found to be higher in North America and the United Kingdom than in Scandinavian countries with no evidence of temporal changes in the cancer incidence.

CONCLUSIONS

The present meta-analysis demonstrated an increased risk of small bowel, colon, extraintestinal cancers, and lymphoma in patients with Crohn's disease. Patients with extensive colonic disease that has been present from a young age should be candidates for endoscopic surveillance; however, further data are required to evaluate the risk of neoplasia over time.

Colorectal neoplasia in Crohn's colitis: a retrospective comparative study with ulcerative colitis

AIMS

To determine the clinicopathological features of colorectal cancer (CRC) in Crohn's disease (CD).

METHODS AND RESULTS

All histological slides from surgical specimens with inflammatory bowel disease-related colorectal neoplasia examined in our hospital between 1990 and 2005 were reviewed. We identified 18 CRCs in 16 patients with CD and compared them with 57 CRCs in 41 patients with ulcerative colitis (UC). We also studied 25 patients with dysplasia without cancer (CD 2, UC 23). When CD and UC were compared, the median age at diagnosis of cancer (CD 52 years, UC 51 years), the frequency of mucinous adenocarcinoma (CD 16.7%, UC 17.5%) and the frequency of dysplasia adjacent to and distal from cancer (CD 56.3 and 37.5%, UC 65.8 and 39%, respectively) were similar. All neoplastic lesions occurred in areas affected by inflammatory bowel disease.

CONCLUSIONS

CRC complicating CD and UC shares many clinicopathological features, in particular similar frequencies of dysplasia, both adjacent and distal, with cancer. Thus, surveillance for patients with Crohn's colitis should be similar to that for patients with UC. Consideration should be given to a more extensive UC-like surgical approach instead of segmental resection of the involved area.

5-Aminosalicylic acid therapy and the risk of colorectal cancer among patients with inflammatory bowel disease

BACKGROUND

Patients with inflammatory bowel disease (IBD) affecting the colon are at increased risk of developing colorectal cancer (CRC). Published data are conflicting about whether 5-aminosalicylic acid (5-ASA) has chemopreventive properties against IBD-related carcinogenesis. The objective of this observational study was to determine if an association between 5-ASA therapy and CRC risk exists in IBD patients.

METHODS

Adult patients with a new CRC diagnosis (n = 18,440) were identified from 2 large administrative claims databases. For each case, 20 control patients with no record of CRC diagnosis or bowel surgery (n = 368,800) were identified.

RESULTS

An IBD diagnosis was associated with a 6- to 7-fold increased risk of CRC (ulcerative colitis, crude odds ratio [OR] = 6.72, 95% CI, 5.79-7.81; Crohn's disease, crude OR = 6.60, 95% CI, 5.56-7.82). Among patients with IBD (364 CRC cases, 1172 controls), exposure to 5-ASA therapy of any dose or duration during the 12 months before CRC diagnosis was not associated with a reduced risk of CRC (OR = 0.97; 95% CI, 0.77-1.23). However, there was a trend toward a decreased risk of CRC with increasing number of mesalamine prescriptions in the previous year, though statistical significance was not achieved (trend P = 0.08).

CONCLUSIONS

Treating IBD patients with 5-ASA medications was not found to have a protective effect against colitis-related CRC when assessed over a short period of exposure.

Increased etheno-DNA adducts in affected tissues of patients suffering from Crohn's disease, ulcerative colitis, and chronic pancreatitis

Chronic inflammatory processes induce oxidative stress and lipid peroxidation (LPO), hereby generating DNA-reactive aldehydes such as trans-4-hydroxy-2-nonenal (HNE). Etheno-modified DNA bases are inter alia generated by reaction of DNA with HNE. Using an immunoaffinity-(32)P-postlabeling method, the authors have investigated etheno-DNA adduct levels 1,N (6)-ethenodeoxyadenosine (epsilondA) and of 3,N (4)-ethenodeoxycytidine (epsilondC) in the pancreas of chronic pancreatitis patients and in the colon of patients with inflammatory bowel disease. Both epsilondA and epsilondC levels were found to be significantly, 3 and 28 times, respectively, elevated in the inflamed pancreatic tissue. In contrast, only epsilondC was found to be increased in affected colonic mucosa of Crohn's disease (19 times) and of ulcerative colitis patients (4 times) when compared to asymptomatic tissues. In all three cancer-prone diseases, the mean epsilondC-levels in tissues were five- to ninefold higher than those of epsilondA. Differential or impaired DNA repair pathways of these adducts, known to occur by two different glycosylases are implicated. K-ras in pancreatic tumors and K-ras and p53 in colon mucosa in long-standing inflammatory bowel disease are known to be highly mutated. The conclusion is that promutagenic etheno-DNA adducts are generated as a consequence of chronic inflammation, acting as a driving force to malignancy in cancer-prone inflammatory diseases.

Screening of colorectal cancer

Cost-effectiveness analyses have shown that the cost per year of life saved by screening with any of the tests recommended is reasonable by US standards. Although the specific results vary among analyses, in general the marginal cost-effectiveness of this screening is less than $25,000 per year of life saved. Screening for CRC was among the highest ranked services in an analysis of the value of preventive services based on the burden of disease prevented and cost-effectiveness. Although the up-front costs vary by screening modality, the long-term cost-effectiveness is similar across screening tests, so that decisions about which options to include--in the long run and from the perspective of society--do not need to be affected heavily by costs. Costs increase out of proportion to benefits with shorter intervals between screening examinations. Screening has provided great opportunities. Screening can prevent CRC by polypectomy and find early-stage cancers for treatment with less morbidity. Screening can reduce the burden of treating advanced cancers and can identify families at increased risk. Screening also has provided a better understanding of the biology of CRC. Screening for CRC should be part of a complete prevention program that includes a healthy lifestyle and familial risk assessment. Individuals with increased familial risk require special screening approaches, whereas individuals with average risk can have more standard screening. The average-risk individuals can be stratified further into persons who require intensive follow-up and persons who require less intensive or no follow-up at all. We are beginning to learn how to apply screening and surveillance approaches based on risk stratification for a more cost-effective approach to conserve resources and reduce complications and costs. Chemoprevention can be added to the program when substantial benefit of agents has been demonstrated. We have a better understanding of the biology of CRC and the technology to intervene in that biology to make a difference in the lives of many people. We have the concepts and technology to reduce substantially the mortality for CRC and even prevent it entirely. Newer screening tests or others yet to be developed may, with time, replace the modern options. Screening should take place with the tests currently available and not wait until something better comes along. In this way, needless suffering and loss of life can be avoided for this leading cause of cancer death. Screening may become even more successful if the promise of new technologies is confirmed and they enter clinical practice. In the last analysis, the best test is the one that gets done and gets done immediately.

Colonoscopic surveillance in inflammatory bowel disease

PURPOSE OF REVIEW

To describe recent findings in the literature aimed at decreasing systematic error in dysplasia surveillance in inflammatory bowel disease.

RECENT FINDINGS

Despite great promise, colonoscopic surveillance in inflammatory bowel disease has yet to be demonstrated to reduce colorectal cancer mortality. In part, this stems from a number of inherent systematic troubles, including low rates of observer agreement among pathologists; lack of consensus on the natural history of dysplasia, particularly low-grade dysplasia; the patchy nature of dysplasia, which leads to sampling error caused by insufficient biopsy by endoscopists; and incomplete patient follow-up. Recent publications that have focused on defining better the natural history of different levels of dysplasia and improving dysplasia identification at the time of colonoscopy may aid in overcoming the flaws of surveillance. The key recent findings include conflicting evidence on the relative danger of flat low-grade dysplasia, the safety of treating polypoid low-grade dysplasia as a benign adenoma in the absence of flat dysplasia in the rest of the colon or the surrounding mucosa, and preliminary support of chromoendoscopy to target dysplasia better during colonoscopy and to limit unnecessary nontargeted biopsies.

SUMMARY

These and other advances stand a reasonable chance of making surveillance a more accurate tool to discriminate between patients with chronic colitis likely to progress to advanced pathology and those less likely to do so. Such advances may result in effective surveillance in which both colorectal cancer mortality and unnecessary colectomy may be limited.

Molecular phenotype of inflammatory bowel disease-associated neoplasms with microsatellite instability

BACKGROUND & AIMS

Patients with inflammatory bowel disease (IBD) are at increased risk of developing colorectal cancer (CRC). We sought to determine the frequency of high-level microsatellite instability (MSI-H) and the mutational and methylation profile of MSI-H IBD-related neoplasms (IBDNs).

METHODS

A total of 124 IBDNs (81 cancers, 43 dysplasias) from 78 patients were studied for the frequency of MSI-H and hypermethylation of 3 target genes: MLH1 , HPP1 , and RAB-32 . Fifteen MSI-H IBDNs were characterized according to their profile of frameshift mutations in 28 mononucleotide repeats and compared with 46 sporadic MSI-H CRCs.

RESULTS

Nineteen of 124 IBDNs were MSI-H. The frequency of frameshift mutations in coding mononucleotide repeats was significantly lower in MSI-H IBDNs than in sporadic MSI-H CRCs for TGFBR2 (7 of 14 vs 34 of 43 samples; P = .047) and ACVR2 (3 of 14 vs 25 of 43 samples; P = .029). In contrast, ICA1 was mutated in 3 of 9 MSI-H IBDNs vs 2 of 54 sporadic MSI-H CRCs ( P = .028). HPP1 and RAB32 methylation was independent of MSI status and was observed in 4 of 59 and 0 of 64 nondysplastic mucosae, 20 of 38 and 1 of 25 dysplasias, and 28 of 61 and 20 of 60 carcinomas, respectively.

CONCLUSIONS

The profiles of coding microsatellite mutations (instabilotypes) differ significantly between MSI-H IBDNs and MSI-H sporadic CRCs. Specifically, TGFBR2 and ACVR2 mutations are significantly rarer in MSI-H IBDNs than in MSI-H sporadic CRCs. Furthermore, HPP1 methylation occurs early, in 7% of nondysplastic and approximately half of dysplastic mucosae, whereas RAB32 methylation occurs at the transition to invasive growth, being rarer in dysplasias.

Colorectal cancer in patients with inflammatory bowel disease

Patients with inflammatory bowel disease (IBD) are subject to increased risks for the development of colorectal cancer (CRC), risks that are attributed to the duration and anatomic extent of disease in patients with ulcerative colitis and Crohn's disease. Although IBD contributes only 1%-2% to all cases of CRC, the mortality rate in patients with a diagnosis of CRC in the setting of IBD is higher than for those afflicted with sporadic cases of CRC. Given the length of time from IBD onset to the development of CRC, surveillance continues to be widely practiced. Although still under development, novel techniques for the earlier detection of dysplastic lesions have moved to the forefront in an attempt to optimize surveillance strategies and decrease the risk of CRC development.

Preventing neoplastic progression in ulcerative colitis

Patients with ulcerative colitis (UC) and Crohn's colitis carry an increased risk for developing colorectal cancer (CRC). Patients with more extensive colitis, greater duration of disease, concomitant primary sclerosing cholangitis, and a family history of CRC are at greatest risk among UC patients. Young age at disease onset and greater inflammatory burden have also been proposed as risk factors. Maneuvers that limit the impact of cancer in colitis include prophylactic colectomy, which is unacceptable to most UC and Crohn's colitis patients, and dysplasia surveillance. Although recommended in a number of practice guidelines, surveillance has not yet been demonstrated to reduce CRC mortality or morbidity. A number of factors, including low levels of agreement among pathologists interpreting surveillance specimens, patients lost to follow-up, failure to recommend colectomy once dysplasia has been discovered, and others, hinder the success of surveillance. In an effort to compensate for the limitations of surveillance, chemoprevention and newer endoscopic and molecular techniques are being assessed for their effectiveness in augmenting or replacing conventional surveillance.

Consensus conference: Colorectal cancer screening and surveillance in inflammatory bowel disease

The idiopathic inflammatory bowel diseases, ulcerative colitis and Crohn's colitis, are associated with an increased risk for developing colorectal cancer. To reduce colorectal cancer mortality in inflammatory bowel disease, most patients and their physicians choose to follow a program of surveillance colonoscopy in an attempt to detect early neoplastic lesions at a curable stage. Colectomy is typically reserved for patients whose biopsy findings are indicative of heightened cancer risk based on interpretation by pathologists. Despite the absence of prospective controlled clinical trials to formally evaluate the benefits, risks, and costs of this approach, enough circumstantial evidence has accrued to warrant its widespread adoption in practice. Nevertheless, no standardized guidelines have yet been set forth to guide the gastroenterologist in performing surveillance. A panel of international experts was assembled to develop consensus recommendations for the performance of surveillance. The findings are presented herein.

Diagnosis and management of dysplasia in patients with inflammatory bowel diseases

Patients with ulcerative colitis and Crohn's colitis face an increased lifetime risk of developing colorectal cancer. Factors associated with increased risk include long duration of colitis, extensive colonic involvement, primary sclerosing cholangitis, a family history of colorectal cancer, and, according to some studies, early disease onset and more severely active inflammation. Although prophylactic proctocolectomy can essentially eliminate the risk of cancer, most patients and their physicians opt instead for a lifelong program of surveillance. This entails regular medical follow-up, management with antiinflammatory and putative chemopreventive agents, and periodic colonoscopic examinations combined with extensive biopsy sampling throughout the colon. The main objective of regular colonoscopy is to detect neoplasia at a surgically curative and preferably preinvasive stage, i.e., dysplasia. An initial screening colonoscopy should be performed 7-8 years from disease onset or immediately in patients with primary sclerosing cholangitis. Surveillance should then continue annually or biennially so long as no dysplasia is found or suspected. Biopsy specimens are graded pathologically as negative, indefinite for dysplasia, low-grade dysplasia, high-grade dysplasia, or invasive cancer. The diagnosis and grading of dysplasia can be very challenging and should be confirmed by an expert pathologist whenever intervention or a change in management is contemplated. If 1 or more biopsy specimens are indefinite for dysplasia, colonoscopy intervals should be reduced. A patient with low- or high-grade dysplasia found in a discrete adenoma-like polyp, but nowhere else, can be safely managed with polypectomy and accelerated surveillance. However, dysplasia of any grade found in an endoscopically nonresectable polyp and high-grade dysplasia found in flat mucosa are both strong indications for proctocolectomy. Evidence further suggests that the same may be true even of low-grade dysplasia in flat mucosa. Chromoendoscopy holds promise for facilitating the endoscopic detection of neoplasia. The clinical application of newer molecular methods to detect neoplasia, particularly gene microarrays and stool DNA testing, also deserve further study.

Anal and rectal cancer in Crohn's disease

Several epidemiological studies have been published regarding the risk of Crohn's disease- associated colorectal cancer. The findings are, however, contradictory and it has been particularly difficult to obtain indisputable information on the incidence of cancer limited to the rectum and the anus. During 1987-2000 rectal or anal cancer was diagnosed in 335 patients in Sweden (153 males, 182 females). In other words, approximately 3 Crohn patients per million inhabitants were diagnosed with rectal or anal cancer every year during that time period which is 1% of the total number of cases. At diagnosis of cancer 36% were aged below 50 years and 58% below 60 years. Corresponding figures for all cases of anal and rectal cancer were 5% and 18%, respectively. Present knowledge from the literature implies that there is an increased risk of rectal and anal cancer only in Crohn's disease patients with severe proctitis or severe chronic perianal disease. However, the rectal remnant must also be considered a risk factor. Multimodal treatment is similar to that in sporadic cancer but proctectomy and total or partial colectomy is added depending on the extent of the Crohn's disease. The outcome is the same as in sporadic cancer at a corresponding stage but the prognosis is often poor due to the advanced stage of cancer at diagnosis. We suggest that six high-risk groups should be recommended annual surveillance after a duration of Crohn's disease of 15 years including extensive colitis, chronic severe anorectal disease, rectal remnant, strictures, bypassed segments and sclerosing cholangitis.

Evidence for oxidative stress in NSAID-induced colitis in IL10-/- mice

The goal of this study was to evaluate for evidence of oxidative stress in colonic inflammation in a novel model of inflammatory bowel disease, nonsteroidal anti-inflammatory drug- (NSAID-) treated interleukin-10-deficient (IL10(-/-)) mice. IL10(-/-) and wild-type (wt) mice were treated with a nonselective NSAID (piroxicam, 200 ppm in the diet) for 2 weeks to induce colitis, and parameters for oxidative stress in the colonic tissues were evaluated. Mean chemiluminescence enhanced with lucigenin in the colons from IL10(-/-) mice treated with piroxicam was more than 5-fold higher than that of the control wt group. Chemiluminescence was inhibited with diphenylethylene iodinium, but not allopurinol, indomethacin, or N-omega-nitro-L-arginine, indicating that flavin-containing enzymes were the source of the reactive oxygen species. Colonic aconitase activity in NSAID-treated IL10(-/-) mice decreased to 50% of the activity of control mice. There was no difference in the total glutathione levels in the colonic mucosa among the groups; however, glutathione disulfide levels were approximately 2-fold greater in the colon of NSAID-treated IL10(-/-) mice as compared with control groups. Immunohistochemistry studies of colons from NSAID-treated IL10(-/-) mice demonstrated intense staining with two antibodies that recognize advanced glycation endproducts formed through glycation and oxidation: anticarboxymethylysine and antipentosidine. The epithelial cells and lamina propria cells in the colons of NSAID-treated IL10(-/-) mice showed immunostaining with antinitrotyrosine, indicating the presence of reactive nitrogen species. Colonic epithelium of IL10(-/-) mice with colitis showed moderate immunostaining for 8-hydroxy-2'-deoxyguanosine in the nuclei. NSAID-treated IL10(-/-) mice treated with diphenylene idodonium chloride (DPI), an irreversible inhibitor of flavoprotein enzymes, experienced significantly reduced inflammation. Taken together, these results strongly indicate the presence of oxidative stress in the inflammatory bowel disease in NSAID-treated IL10(-/-) mice and suggests a role for oxidative stress in the pathophysiology of this model of inflammatory bowel disease.

Colon carcinogenesis in inflammatory bowel disease: applying molecular genetics to clinical practice

Although both sporadic colorectal cancer (CRC) and colitis-associated CRC arise from dysplastic precursor lesions and share several molecular alterations, the nature of the dysplasia and the frequency and timing of several of the key molecular changes differ enough to consider colitis-associated CRC a rather unique entity. To date, cancer surveillance in both ulcerative colitis and Crohn's colitis rests upon the detection of dysplasia. However, because there are considerable limitations to the detection and interpretation of dysplasia, there is a need for other molecular markers to complement the histologic analysis of dysplasia. Because patients with inflammatory bowel disease (IBD) undergo repeated, periodic surveillance colonoscopies, it affords an opportunity to study marker expression over time. Of the few markers that have been studied chronologically, aneuploidy, p53, and mucin-associated sialyl-Tn antigen expression each hold promise as markers of CRC risk in IBD. It will be important to study whether these markers, or other panels of gene or protein expression, can identify patients at highest risk for developing CRC in future clinical studies.

Malignancies in inflammatory bowel disease: fact or fiction?

BACKGROUND

The association between ulcerative colitis (UC), Crohn disease (CD) and colorectal cancer (CRC) has been confirmed in several studies. The aim of this study was critical analysis of the relation between IBD and malignancy.

METHODS

Review of the literature.

RESULTS

In UC, the extent of the disease, its duration and start at a young age are risk factors for the development of CRC. Primary sclerosing cholangitis and colonic strictures are additional risk factors for development of CRC. The relation between azathioprine or 6-MP and the development of lymphomas is a subject of debate. The administration of anti-TNF-alpha has produced some concern about the development of lymphomas in CD. However, at present there is no evidence of lymphomas caused by anti-TNF-alpha in CD. On the contrary, some drugs seem to have a preventive effect on CRC development in UC. 5-aminosalicylic acid in particular and to a lesser extent sulphasalazine have prevented the development of CRC significantly in retrospective studies. In CD, there is no strong relationship between the disease and the development of CRC or other malignancies. Only the development of small-bowel carcinoma is reported with a much higher frequency.

CONCLUSIONS

There is a correlation with UC and the development of CRC. For CD, this correlation is less firmly established. There is a possible, but not proven, relation between AZA/6-MP use and the development of lymphoma in IBD. There is also a probable relationship between CD and the development of small-bowel carcinoma. In some retrospective studies, the use of 5-aminosalicylic or sulphasalazine has been shown to prevent the development of CRC in UC.

Cancer prevention in patients with inflammatory bowel disease

Colorectal cancer is an important, and often dreaded, consequence of long-standing UC and Crohn's colitis. Surveillance colonoscopy, despite its limitations, is beneficial for detecting earlier stage cancers and, probably, mortality reduction. Agents such as anti-inflammatory medications, folic acid, and ursodeoxycholic acid show promise for chemoprevention in this disease. Future research will help to define better the natural history of dysplasia in IBD, and to determine how molecular approaches may be integrated into surveillance programs to reduce CRC risk.

Small bowel adenocarcinoma presenting as a first manifestation of Crohn's disease: report of a case, and a literature review

Small bowel Crohn's disease has been related to an increased incidence of small bowel adenocarcinoma, but the total number of reported cases is small. We present an interesting case of a young male patient with nephrolithiasis in childhood, an atypical intermittent history of diarrhoea also since his childhood, who developed obstructive ileus and underwent an urgent operation. The operation revealed a stenosis of the ileum owing to a mass, which proved to be a small bowel adenocarcinoma. One month later, the patient underwent a curative surgical resection of the tumour with additional lymphadenectomy, followed by chemotherapy for 6 months. Since then, the patient had mild diarrhoea but enteroclysis was normal. Approximately 2 years after the resection of the tumour, a new ileocolonoscopy demonstrated deep ulcerations of the terminal ileum and the adjacent area of the colon as well as anal ulcerations. The new biopsy specimens were convincing for Crohn's disease. There were no signs of residual or relapsing cancer. There is growing evidence that Crohn's disease is one of the triggering factors for the development of small bowel adenocarcinoma. Underlying Crohn's disease should be suspected in a young patient with an atypical history of diarrhoea and small bowel adenocarcinoma.