Similarity of colorectal cancer in Crohn's disease and ulcerative colitis: implications for carcinogenesis and prevention

Matrix metalloproteinase-9 functions as a tumor suppressor in colitis-associated cancer

There is a well-documented association of matrix metalloproteinase-9 (MMP-9) and receptor Notch-1 overexpression in colon cancer. We recently showed that MMP-9 is also upregulated in colitis, where it modulates tissue damage and goblet cell differentiation via proteolytic cleavage of Notch-1. In this study, we investigated whether MMP-9 is critical for colitis-associated colon cancer (CAC). Mice that are wild type (WT) or MMP-9 nullizygous (MMP-9(-/-)) were used for in vivo studies and the human enterocyte cell line Caco2-BBE was used for in vitro studies. CAC was induced in mice using an established carcinogenesis protocol that involves exposure to azoxymethane followed by treatment with dextran sodium sulfate. MMP-9(-/-) mice exhibited increased susceptibility to CAC relative to WT mice. Elevations in tumor multiplicity, size, and mortality were associated with increased proliferation and decreased apoptosis. Tumors formed in MMP-9(-/-) mice exhibited expression of p21(WAF1/Cip1) and increased expression of beta-catenin relative to WT mice. In vitro studies of MMP-9 overexpression showed increased Notch-1 activation with a reciprocal decrease in beta-catenin. Notch and beta-catenin/Wnt signaling have crucial roles in determining differentiation and carcinogenesis in gut epithelia. Despite being a mediator of proinflammatory responses in colitis, MMP-9 plays a protective role and acts as a tumor suppressor in CAC by modulating Notch-1 activation, thereby resulting in activation of p21(WAF1/Cip1) and suppression of beta-catenin.

Induction of epigenetic alterations by chronic inflammation and its significance on carcinogenesis

Chronic inflammation is deeply involved in development of human cancers, such as gastric and liver cancers. Induction of cell proliferation, production of reactive oxygen species, and direct stimulation of epithelial cells by inflammation-inducing factors have been considered as mechanisms involved. Inflammation-related cancers are known for their multiple occurrences, and aberrant DNA methylation is known to be present even in noncancerous tissues. Importantly, for some cancers, the degree of accumulation has been demonstrated to be correlated with risk of developing cancers. This indicates that inflammation induces aberrant epigenetic alterations in a tissue early in the process of carcinogenesis, and accumulation of such alterations forms "an epigenetic field for cancerization." This also suggests that inhibition of induction of epigenetic alterations and removal of the accumulated alterations are novel approaches to cancer prevention. Disturbances in cytokine and chemokine signals and induction of cell proliferations are important mechanisms of how inflammation induces aberrant DNA methylation. Aberrant DNA methylation is induced in specific genes, and gene expression levels, the presence of RNA polymerase II (active or stalled), and trimethylation of H3K4 are involved in the specificity. Expression of DNA methyltransferases (DNMTs) is not necessarily induced by inflammation, and local imbalance between DNMTs and factors that protect genes from DNA methylation seems to be important.

Epithelial vanin-1 controls inflammation-driven carcinogenesis in the colitis-associated colon cancer model

BACKGROUND

Vanin-1 is an epithelial pantetheinase that provides cysteamine to tissue and regulates response to stress. Vanin-1 is expressed by enterocytes, and its absence limits intestinal epithelial cell production of proinflammatory signals. A link between chronic active inflammation and cancer is illustrated in patients with ulcerative colitis, who have an augmented risk of developing colorectal cancer. Indeed, sustained inflammation provides advantageous growth conditions to tumors. We examined whether epithelial cells affect tumorigenesis through vanin-1-dependent modulation of colonic inflammation.

METHODS

To vanin-1(-/-) mice, we applied the colitis-associated cancer (CAC) protocol, which combines injection of azoxymethane (AOM) with repeated administrations of dextran sodium sulfate (DSS). We numbered tumors and quantified macrophage infiltration and molecular markers of cell death and proliferation. We also tested DSS-induced colitis. We scored survival, tissue damages, proinflammatory cytokine production, and tissue regeneration. Finally, we explored activation pathways by biochemical analysis on purified colonic epithelial cells (CECs) and in situ immunofluorescence.

RESULTS

Vanin-1(-/-) mice displayed a drastically reduced incidence of colorectal cancer in the CAC protocol and manifested mild clinical signs of DSS-induced colitis. The early impact of vanin-1 deficiency on tumor induction was directly correlated to the amount of inflammation and subsequent epithelial proliferation rather than cell death rate; all this was linked to the modulation of NF-kappaB pathway activation in CECs.

CONCLUSIONS

These results emphasize the importance of the intestinal epithelium in the control of mucosal inflammation acting as a cofactor in carcinogenesis. This might lead to novel anti-inflammatory strategies useful in cancer therapy.

Innate immune signaling by Toll-like receptor-4 (TLR4) shapes the inflammatory microenvironment in colitis-associated tumors

BACKGROUND

Patients with ulcerative colitis are at increased risk for developing colorectal cancer. We have shown that Toll-like receptor-4 (TLR4) is overexpressed in human colitis-associated cancer (CAC) and that mice deficient in TLR4 are markedly protected against colitis-associated neoplasia. We wished to elucidate the specific contributions of TLR4 signaling by myeloid cells and colonic epithelial cells (CEC) in colitis-associated tumorigenesis.

METHODS

TLR4-deficient mice or wildtype littermates (WT) were transplanted with bone marrow (BM) cells: TLR4(-/-) BM-->WT mice (TLR4-expressing CEC) and WT BM-->TLR4(-/-) mice (TLR4-expressing myeloid cells). Colitis-associated neoplasia was induced by azoxymethane (AOM 7.3 mg/kg) injection and 2 cycles of dextran sodium sulfate (DSS) treatment.

RESULTS

The number and size of dysplastic lesions were greater in TLR4(-/-) BM-->WT mice than in WT BM-->TLR4(-/-) mice (P < 0.005). Histologically, TLR4(-/-) BM-->WT mice had greater numbers of mucosal neutrophils and macrophages compared to WT BM-->TLR4(-/-) mice. The chemokines KC and CCL2, important in recruitment of neutrophils and macrophages, respectively, were induced in mice expressing TLR4 in CEC rather than the myeloid compartment. The lamina propria infiltrate of mice expressing TLR4 in CEC was characterized by macrophages expressing Cox-2. Moreover, mice expressing TLR4 in CEC rather than the myeloid compartment had increased production of amphiregulin and EGFR activation.

CONCLUSIONS

These findings indicate that TLR4 signaling on CEC is necessary for recruitment and activation of Cox-2-expressing macrophages and increasing the number and size of dysplastic lesions. Our results implicate innate immune signaling on CEC as a key regulator of a tumor-promoting microenvironment.

Colorectal carcinoma in indeterminate colitis

BACKGROUND

For all the interest in the natural history of colorectal cancer (CRC) in ulcerative colitis (UC) and Crohn's disease (CD), surprisingly few data have been published regarding CRC in indeterminate colitis (IC). We present our experience with 15 cases of IC-associated CRC in order to assess their clinicopathological features and to determine their survival rates.

METHODS

We retrospectively reviewed the medical records of patients with IC admitted to the Mount Sinai Hospital between 1994 and 2007 and who developed CRC. All patients were operated on and follow-up was complete for all patients to the closing date of study or to the time of death.

RESULTS

A total of 19 adenocarcinomas were present in this series. There were 3 patients with multiple cancers; all cancers occurred in segments of colitis. The mean age at onset of IC was 28 years and the average time progression from the IC diagnosis to CRC was 19 years. Dysplasia was detected in 10 of the cases; 3 patients had mucinous tumors. Five patients had stage I tumors; 5 stage II; 4 stage III; 1 stage IV. There were 4 deaths due to CRC. The overall 5-year survival was 42%.

CONCLUSIONS

CRC in IC shares most of the clinical and pathologic features as well as survival outcomes with CRC that occurs in the most prevalent forms of inflammatory bowel disease (IBD), UC and CD. Surveillance regimens currently used in the other forms of IBD seem applicable to IC patients as well.

Decreasing time-trends of colorectal cancer in a large cohort of patients with inflammatory bowel disease

BACKGROUND & AIMS

Inflammatory bowel disease (IBD) is a risk factor for colorectal cancer (CRC). There have been marked changes in the management and treatment of IBD over the past decades, but little is known about how these changes have impacted morbidity and mortality (time trends in risk) of CRC in patients with IBD.

METHODS

We assessed cancer occurrence and mortality in a large population-based cohort of patients with IBD who were diagnosed from 1954 to 1989 (n = 7607). Through register links, we collected data on vital status of all registered cases of CRC, as well as intestinal surgeries and mortalities from CRC through 2004. Relative risks for CRC incidence and mortality, by calendar period of follow-up evaluation, were assessed within the cohort (using Poisson regression and taking age, sex, extent of IBD, and time since IBD diagnosis into account) and also compared with the general population using standardized incidence and mortality ratios.

RESULTS

During 198,227 person-years of follow-up evaluation for the 7607 patients with IBD, 188 new cases of CRC were observed (crude incidence, 95 per 100,000; 95% confidence interval, 82-109); 92 deaths from CRC were registered. Within the IBD cohort, as well as vs the general population, the incidence of CRC showed a tendency towards a decline whereas the mortality from CRC decreased several-fold from the 1960s through 2004.

CONCLUSIONS

Over the past 35 years, the risk of diagnosis of CRC in patients with IBD has not declined significantly, but the risk of dying of CRC has decreased substantially.

Inhibition of cell proliferation and invasion in a human colon cancer cell line by 5-aminosalicylic acid

BACKGROUND

5-Aminosalicylic acid lacks the well-known side effects associated with the long-term use of non-steroidal anti-inflammatory drugs. We investigated anti-carcinogenic mechanisms of 5-aminosalicylic acid on a colon cancer cell line.

METHODS

MTT analysis was performed for various colon cancer cell lines. The expression of NF-kappaB and metalloproteinases was examined in either HT-29 cells treated with IL-1beta and/or 5-aminosalicylic acid. Matrigel assay was used to evaluate invasive potential of HT-29 cells. Analysis of a cDNA microarray containing 8700 genes was performed to identify the alteration of gene expression in response to treatment to 5-aminosalicylic acid.

RESULTS

The use of MTT analysis showed that 5-aminosalicylic acid suppressed the growth of HT-29 cells. The activity of NF-kappaB was also decreased by combined-treatment with IL-1beta and 5-aminosalicylic acid. The use of an ELISA and zymography demonstrated that MMP-2 and MMP-9 enzyme activity were decreased in HT-29 cells by treatment with various concentration of 5-aminosalicylic acid. A matrigel analysis demonstrated that 5-aminosalicylic acid treatment on HT-29 significantly inhibited the invasiveness of the cells. In cDNA microarray, 163 genes following 5-aminosalicylic acid exposure showed altered expression.

CONCLUSIONS

This study indicated that 5-aminosalicylic acid suppresses the growth of human colon cancer cells and is able to inhibit MMPs expression via NF-kappaB mediated cell signals and invasiveness.

Trends of ulcerative colitis-associated colorectal cancer in Korea: A KASID study

BACKGROUND AND AIM

The number of patients with ulcerative colitis (UC) in Korea has increased. In addition, the number of patients with colorectal cancer (CRC) associated with UC has also increased. Therefore, this population-based nationwide study was conducted to investigate the incidence of CRC in patients with UC in Korea and compare these results to those of studies conducted in other countries.

METHODS

The Korean Association for the Study of Intestinal Diseases (KASID) reviewed 7061 cases of UC that occurred between 1970 and 2005 and found a total of 26 cases of CRC.

RESULTS

The overall prevalence of CRC in patients with UC was 0.37%. In addition, the estimated cumulative risk of UC-associated CRCs was 0.7% for patients that had UC for 10 years, 7.9% for patients that had UC for 20 years, and 33.2% for patients that had UC for 30 years. The mean age at the time of diagnosis with CRC was 49.6 years, and the mean duration of UC prior to the development of CRC was 11.5 years. Most UC-associated CRCs were diagnosed after they were already in advanced stages; however, the stage at diagnosis was lower in patients that had good compliance with medical treatment.

CONCLUSION

The cumulative incidence of UC-associated CRCs in Korea was found to be comparable to that of western countries. The overall occurrence of UC-associated CRC in Korea may be growing, therefore, intensive surveillance colonoscopy and constructive chemoprevention should be encouraged to enable early detection and treatment of UC-associated CRCs in Korea.

Acquired risk factors for colorectal cancer

The risk of developing colorectal cancer (CRC) is influenced by several acquired risk factors, including environmental exposures and comorbid medical conditions that are partially genetic in nature. These risk factors are based on data almost exclusively derived from observational studies. Because of the possibility of bias due to confounding, these acquired risk factors should not be automatically assumed to be causative, and in fact some may not be truly independent risk factors. Acquired risk factors include the following categories: 1) dietary factors, 2) lifestyle factors, 3) side-effects of medical interventions, and 4) comorbid medical conditions. Dietary factors that potentially increase the risk of CRC include low fruit, vegetable, or fiber intake, high red meat or saturated fat consumption, and exposure to caffeine or alcohol. Of these factors, the significance of low fruit, vegetable, and fiber intake has been called into question because of contradictory results from large observational studies and negative results from randomized trials. The association of high red meat or saturated fat consumption with increased CRC risk is supported by the preponderance of observational data. Lifestyle factors include lack of exercise and smoking. These risk factors are supported by observational data of moderate quality. Medical interventions that may increase the risk of CRC include pelvic irradiation, cholecystectomy, and ureterocolic anastomosis after major surgery of the urinary and intestinal tracts. Aside from cholecystectomy, these risk factors are supported by observational data from small studies only, therefore their validity is not well established. Finally, comorbid medical conditions that are associated with increased risk of CRC include Barrett's esophagus, human immunodeficiency virus infection, acromegaly, and inflammatory bowel disease. The association between inflammatory bowel disease and CRC is well established and it forms the basis for widely adopted colonoscopic surveillance recommendations from national medical organizations. The other factors are supported by limited observational data only and are still controversial.

Two distinct groups of colorectal cancer in inflammatory bowel disease

BACKGROUND

The histological variability in colitis-associated colorectal cancer (CRC in inflammatory bowel disease [IBD]) and the association to clinical factors is unknown.

METHODS

In population-based material including 67 patients with CRC in IBD, histopathology of the cancers and tissue samples from different colorectal localizations were reevaluated, and relationships to clinical factors analyzed.

RESULTS

Forty-three of 60 patients (75%) showed dysplasia in the colorectum apart from the cancer, while 17 (25%) had no dysplasia at cancer diagnosis. Mean age at onset of IBD was 22 years in patients with and 34 years in patients without dysplasia (P = 0.01). The mean duration of colitis-CRC interval was 21 years in patients with and 16 years in patients without dysplasia (P = 0.02). The latter group included all patients with a colitis-CRC interval <10 years. Active inflammation was more likely to occur in patients with dysplasia (odds ratio [OR] 4.2). The 2 groups were not discriminated by gender, family history of CRC or IBD, diagnosis of PSC, medical treatment, active symptoms, or histological features like type of cancer and differentiation. In multiple logistic regression analysis the age at onset of IBD was the strongest predictive variable for dysplasia at cancer diagnosis (P = 0.025).

CONCLUSIONS

Widespread neoplasia occurs in the majority of cases with CRC in IBD and is associated with early onset of IBD. Localized neoplasia occurs in about a quarter of the patients and shows an association with late-onset IBD. The 2 groups probably represent different pathogenetic entities of neoplasia in IBD. This might have consequences for surveillance strategies.

Risks and clinical features of colorectal cancer complicating Crohn's disease in Japanese patients

BACKGROUND AND AIM

No reports on the relative risk of development of colorectal cancer (CRC) in Japanese patients with Crohn's disease (CD) have been published. The present study aimed to investigate the relative risk and the clinical features of CRC complicating CD among patients managed at Fukuoka University Chikushi Hospital, Fukuoka, Japan (a tertiary referral center for inflammatory bowel diseases).

METHODS

The clinical backgrounds were analyzed of 512 patients with CD who have been treated by our department during the last 20-year period (1985-2005) (total 6212.6 person years at risk). The standardized incidence ratio (SIR) refers to the relative risk of CRC in the subjects as compared with that in a sex- and age-matched healthy population.

RESULTS

There were six cases with CRC. The SIR was significantly higher (3.2-fold higher; 95% confidence interval, 1.2-6.9 P < 0.05) in the CD group than in the healthy population. The significant risk factors identified were female sex, mixed small and large bowel type, observation period over 20 years, onset of CD at less than 25 years of age, presence of anal disease, and positive history of surgery. The prognosis for the six cases with CRC was very poor (five cases died within 1.5 years).

CONCLUSION

The risk of CRC in longstanding CD in Japan was similar to that in Western countries. The necessity of surveillance in the management of CD would also need to be discussed in the near future, especially in CD patients with anal lesions or fistulae, and are particularly important in patients with a 20-year or more history of CD.

Synchronous multifocal colorectal carcinoma in a patient with delayed diagnosis of ulcerative pancolitis

Patients with ulcerative colitis face an increased lifetime risk of developing colorectal cancer. Relatively often, the patients present with multiple synchronous or metachronous tumors. Here, we report a case of ulcerative colitis-associated synchronous multifocal colorectal carcinomas. A 36-year-old male presented with symptoms of persisting abdominal pain that had lasted for several months. Histology of the colonic biopsies showed active ulcerative pancolitis with extensive multifocal low- and high-grade dysplasia. Regardless of the diagnosis and medical advice, the patient initially refused therapy, and proctocolectomy was delayed for 12 months. In the resection specimen, four clinically unsuspected, partly mucinous adenocarcinomas accompanied by several foci of low- and high-grade dysplasia were found in the left colon and rectum. At the time of colectomy, advanced tumor stage was diagnosed and classified as pT3c(4) pN1(2/120) M0 V1 R0, UICC stage IIIB, G2. Furthermore, a mucinous cystadenoma was found in the appendix in the setting of ulcerative colitis. We discuss the neoplastic transformation, current surveillance guidelines, and the therapeutic management in ulcerative colitis.

Colorectal cancer in inflammatory bowel disease

Patients with long-standing inflammatory bowel disease have an increased risk of developing colorectal cancer (CRC). CRC risk increases with longer duration of colitis, greater anatomic extent of colitis, the presence of primary sclerosing cholangitis, family history of CRC and severity of inflammation of the colon. Chemoprevention includes aminosalicylates, ursodeoxycholic acid, and possibly folic acid. To reduce CRC mortality in IBD, colonoscopic surveillance remains the major way to detect early mucosal dysplasia. When dysplasia is confirmed, proctocolectomy is considered for these patients. 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. New endoscopic and molecular screening approaches may further refine our current surveillance guidelines and our understanding of the natural history of dysplasia.

Increased susceptibility of Nrf2 knockout mice to colitis-associated colorectal cancer

The nuclear factor-erythroid 2-related factor 2 (Nrf2) plays a critical role in protecting various tissues against inflammation, which is a potential risk factor for colorectal and other cancers. Our previously published mouse model work showed that Nrf2 helps protect against dextran sulfate sodium (DSS)-induced colitis/inflammation, and others have shown that Nrf2 helps protect against inflammation-associated colorectal carcinogenesis (aberrant crypt foci). The present study extended these important earlier findings by exploring the role of Nrf2 in colitis-associated colorectal cancer in a mouse model involving azoxymethane/DSS-induced colorectal carcinogenesis in Nrf2 knockout mice. Azoxymethane/DSS-treated Nrf2 knockout mice had increased incidence, multiplicity, and size of all colorectal tumors, including adenomas, versus treated wild-type (WT) mice, and the proportion of tumors that were adenocarcinoma was much higher in knockout (80%) versus WT (29%) mice. Compared with WT mice, knockout mice also had increased markers of inflammation in tumor tissue (cyclooxygenase-2 and 5-lipoxygenase expressions and prostaglandin E(2) and leukotriene B(4) levels) and in inflamed colonic mucosa (nitrotyrosine expression), supporting the association of knockout mouse tumor formation with inflammation. The phase II detoxifying/antioxidant enzymes NAD(P)H-quinone reductase 1 and UDP-glucurosyltransferase 1A1 were elevated in the normal mucosa of WT, but not Nrf 2 knockout, mice treated with azoxymethane/DSS. Our findings show that Nrf2 plays a critical role in protecting against inflammation-associated colorectal cancer.

Role for epithelial dysregulation in early-onset colitis-associated colon cancer in Gi2-alpha-/- mice

BACKGROUND

Inflammatory bowel disease (IBD) is a risk factor for developing colorectal cancer but the mechanisms are poorly characterized. Mice lacking the G-protein alpha subunit Gi2-alpha spontaneously develop colitis and colon cancer with high penetrance. Compared to canonical Wnt/APC signaling-based animal models of colon cancer, the tumors in Gi2-alpha-/- mice more closely recapitulate the features of IBD-associated cancers seen in humans. They are predominantly right-sided, multifocal, mucinous, and arise from areas of flat dysplasia.

METHODS

In evaluating the potential contribution of epithelial Gi2-alpha signaling to this phenotype, we found that Gi2-alpha-/- colonic epithelium is hyperproliferative even before the onset of colitis, and resistant to the induction of apoptosis. We generated colon cancer cell lines overexpressing dominant-negative Gi2-alpha.

RESULTS

Like other cells lacking Gi2-alpha, these cells release less arachidonic acid, an important antiinflammatory and epithelial growth regulator. They are also hyperproliferative and resistant to camptothecin-induced apoptosis and caspase-3 activation.

CONCLUSIONS

The colitis-associated cancers in Gi2-alpha-/- mice appear very similar to those seen in human IBD patients, and Gi2-alpha is a direct negative regulator of colonic epithelial cell growth.

Colorectal cancer and dysplasia in inflammatory bowel disease

Both ulcerative colitis and Crohn’s disease carry an increased risk of developing colorectal cancer. Established risk factors for cancer among patients with inflammatory bowel disease (IBD) include the younger age at diagnosis, greater extent and duration of disease, increased severity of inflammation, family history of colorectal cancer and coexisting primary sclerosing cholangitis. Recent evidence suggests that current medical therapies and surgical techniques for inflammatory bowel disease may be reducing the incidence of this complication. Nonetheless heightened vigilance and a careful, comprehensive approach to prevent or minimize the complications of invasive cancer are warranted in this unique cohort of patients. Current guidelines for the prevention and early detection of cancer in this high risk population are grounded in the concept of an inflammation-dysplasia-carcinoma sequence. A thorough understanding of the definition and natural history of dysplasia in IBD, as well as the challenges associated with detection and interpretation of dysplasia are fundamental to developing an effective strategy for surveillance and prevention, and understanding the limitations of the current approach to prevention. This article reviews the current consensus guidelines for screening and surveillance of cancer in IBD, as well as presenting the evidence and rationale for chemoprevention of cancer and a discussion of emerging technologies for the detection of dysplasia.

Surveillance of patients at increased risk of colon cancer: inflammatory bowel disease and other conditions

Colorectal cancer (CRC) is the second most common cause of cancer-related mortality in the United States. Colonoscopic screening with removal of adenomatous polyps in individuals at average risk is known to decrease the incidence and associated mortality from colon cancer. Certain conditions, notably inflammatory bowel disease involving the colon, a family history of polyps or cancer, a personal history of colon cancer or polyps, and other conditions such as acromegaly, ureterosigmoidostomy, and Streptococcus bovis bacteremia are associated with an increased risk of colonic neoplasia. This article reviews the CRC risks associated with these conditions and the currently recommended surveillance strategies.

Colonography by CT, MRI and PET/CT combined with conventional colonoscopy in colorectal cancer screening and staging

Colorectal cancer (CRC) remains a leading cancer killer worldwide. But the disease is both curable and preventable at an early stage. Regular CRC cancer screening has been shown to reduce the risk of dying from CRC. However, the importance of large-scale screening is only now starting to be appreciated. This article reviews a variety of imaging procedures available for detecting ulcerative colitis (UC) and Crohn’s disease (CD), polyps and CRC in their early stage and also presents details on various screening options. Detecting, staging and re-staging of patients with CRC also require multimodality, multistep imaging approaches. Staging and re-staging with conventional colonoscopy (CC), computer tomography colonography (CTC), magnetic resonance colonography (MRC) and positron emission tomography/computer tomography colonography (PET/CTC) are of paramount importance in determining the most appropriate therapeutic method and in predicting the risk of tumor recurrence and overall prognosis. The advantages and limitations of these modalities are also discussed.

Role of Toll-like receptors in gastrointestinal malignancies

Mounting evidence supports the tenet that innate immune responses to luminal microbes participate in the development of gastrointestinal malignancies. The gastrointestinal tract is relatively unique in that it has evolved in the presence of diverse enteric microflora. Intestinal flora is required to develop a normal adaptive immune response in the periphery. With the characterization of the innate immune system, we have begun to understand the adaptations the intestine has made to the microbiota. The interaction between the microbiota and the intestinal mucosa through Toll-like receptors (TLRs) is required to maintain intestinal homeostasis. In particular, intestinal epithelial cells and lamina propria mononuclear cells such as antigen-presenting cells and T cells must respond to breaches in the mucosal barrier by activating TLR-dependent pathways that result in increased epithelial proliferation, wound healing and recruitment of acute inflammatory cells. In the setting of chronic inflammation such as Helicobacter pylori (H. pylori) infection in the stomach or idiopathic inflammatory bowel disease, the process of repair may eventually result in carcinogenesis. The following review highlights human and animal data that support a role for innate immune responses and TLRs specifically in promoting gastrointestinal malignancies. Candidate pathways linking TLRs to gastrointestinal malignancies include activation of nuclear factor-kappaB and cyclooxygenase-2. Studying the link between innate immune signaling and gastrointestinal malignancies offers the possibility to identify novel ways to both prevent and treat gastrointestinal cancer.

Neoplastic precursor lesions related to the development of cancer in inflammatory bowel disease

Dysplasia is an intermediate stage in the progression from inflammation to cancer in patients with inflammatory bowel disease. Clinically, dysplasia is used to define appropriate endpoints for colectomy in high-risk patients undergoing endoscopic surveillance. Surveillance is currently the only credible alternative to prophylactic colectomy for high-risk patients. The success of surveillance can be maximized by adherence of gastroenterologists to recommended procedural guidelines, adherence of pathologists to standardized histological criteria and nomenclature, and a joint commitment to close clinical-pathological communication. Technical enhancements to conventional endoscopy hold promise of improved efficiency and accuracy. Molecular-based testing may have a future role for risk stratification and early detection of neoplasia in inflammatory bowel disease.

Crohn's disease-associated colorectal cancer in Japan: report of four cases

PURPOSE

We report four cases of Crohn's disease (CD)-associated colorectal cancer (CRC) in our department. CASE 1: A 42-year-old Japanese man had a 14-year history of ileocolon CD. He had a history of an ileocecal resection and a stricture plasty. At the age of 42, sigmoid colostomy was performed because of the deterioration of the anal stenosis. After this operation, the perianal pain had remained, and a magnetic resonance imaging scan revealed a rectal tumor. CASE 2: A 30-year-old Japanese man had a 13-year history of ileocolon CD. He had a history of an ileostomy, a subtotal colectomy, and ileo-rectal anastomosis. At the age of 30, he had perianal pain, and a colonoscopy revealed a rectal cancer. An abdomino-perineal resection of the remnant rectum was performed. CASE 3: A 46-year-old Japanese man had a 9-year history of ileocolon CD. He experienced abdominal fullness. Colonoscopy revealed an ascending colon cancer. He underwent a subtotal colectomy and ileo-rectal anastomosis. CASE 4: A 33-year-old Japanese woman had a 16-year history of ileocolon CD. She had no changes in symptoms of CD. Surveillance colonoscopy revealed a transverse colon cancer. She underwent a subtotal colectomy and ileo-rectal anastomosis.

CONCLUSION

As the number of patients with CD and with CD-associated CRC has increased in Japan, CD-associated CRC, as noted in these patients, should be kept in mind in the management of patients with CD. In addition, a surveillance system of patients with CD should be established and should prompt further study about CD-associated CRC.

Operative management of Crohn's disease of the colon including anorectal disease

Evaluation and management of the patient who has Crohn's disease of the colon, rectum, and anus is challenging for even the most experienced provider. Because of its broad spectrum of presentation, recurrent nature, and potential for high morbidity, the surgeon needs to not only treat the acute situation but also keep in mind the potential long-term ramifications. Although there are exciting new medications and treatment modalities yielding promising results, surgery continues to remain at the forefront for the care of these patients. This article reviews various surgical options for the patient who has Crohn's disease of the colon, rectum, and perianal region with emphasis on symptomatic resolution and optimization of function.

Role of chromoendoscopy in colon cancer surveillance in inflammatory bowel disease

Inflammation in the intestine is a well-known risk factor for neoplastic changes in the mucosa. In fact, it has been shown that long-standing ulcerative colitis and colonic Crohn's disease have a significantly increased risk for developing colorectal cancer, although the estimates vary widely between studies. Conventional colonoscopy is effective in detecting polypoid changes in the mucosa. However, it is now generally accepted that neoplastic changes in colitis are frequently flat and depressed, which are easily missed by use of routine colonoscopy. The introduction of chromoendoscopy, especially in combination with magnifying endoscopy, has greatly advanced our means to detect and differentiate neoplastic lesions in the colorectum. Accumulating evidence-based data indicate that implementation of chromoendoscopy into colon cancer surveillance protocols for patients with inflammatory bowel disease is effective. However, the introduction of chromoendoscopy into surveillance programs requires meticulous training and further studies to compare the value of chromoendoscopy to newer endoscopic devices and techniques, such as narrow band imaging.

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.

Magnifying chromoscopy, a novel and useful technique for colonoscopy in ulcerative colitis

Ulcerative colitis (UC) is a chronic inflammatory bowel disorder characterized by exacerbations and remissions. The degree of inflammation as assessed by conventional colonoscopy is a reliable parameter of disease activity. However, even when conventional colonoscopy suggests remission and normal mucosal findings, microscopic abnormalities may persist, and relapse may occur later. Patients with long-standing, extensive ulcerative colitis have an increased risk of developing colorectal cancer. Ulcerative colitis-associated colorectal cancer is characterized by an early age at onset, poorly differentiated tumor cells, mucinous carcinoma, and multiple lesions. Early detection of dysplasia and colitic cancer is thus a prerequisite for survival. A relatively new method, magnifying chromoscopy, is thought to be useful for the early detection and diagnosis of dysplasia and colitic cancer, as well as the prediction of relapse.

Microsatellite instability in long-standing ulcerative colitis

OBJECTIVE

Ulcerative colitis (UC) is a chronic inflammatory disease of the colon associated with a high risk of developing colorectal cancer. Several genetic alterations have been documented in dysplasia and cancer developing in UC. Concerning microsatellite instability (MSI), many contradictory results have been published. We therefore analysed a large, well-characterized UC material for MSI to elucidate its significance in long-standing UC.

MATERIAL AND METHODS

From 33 patients, a total of 159 microdissected lesions and 165 mucosa samples obtained adjacent to the tissue blocks were analysed for MSI using the five standard markers recommended by the National Cancer Institute; D2S123, D5S346, D17S250, BAT-25 and BAT-26. In addition, 12 of the patients were investigated by a mini-satellite marker at the D1S7 locus.

RESULTS

High-level MSI (MSI-H) was detected in one villous adenoma with high-grade dysplasia and right-sided location. This represents 3.6% (1/28) of dysplastic mucosa investigated. No other lesions showed MSI in the five standard markers or at the D1S7 locus.

CONCLUSIONS

This study suggests that MSI is rare in UC-related neoplasia as well as non-neoplastic lesions, and does not contribute to the development of dysplasia.

Intestinal cancer in patients with Crohn's disease

BACKGROUND

Surveillance of intestinal cancer in Crohn's disease (CD) has often been advocated. To date, no clear evidence exists whether CD patients are at special risk for intestinal cancer. An increased incidence of small bowel adenocarcinoma is suggested. However, recent figures also suggest an increased risk of CD associated colorectal cancer. We report our experience with 10 cases of CD complicated by intestinal adenocarcinoma.

MATERIALS AND METHODS

Our institutional database included 330 patients treated for CD between 1988-2005. Data of patients that developed carcinoma within Crohn's lesions of either small or large bowel were analyzed.

RESULTS

Ten patients were diagnosed with CD complicated by carcinoma. In nine patients, cancer was present in the colorectum and in one, in Crohn's ileitis. Tumors were in conjunction with fistulae in three and developed within strictures in five patients. Mean age at the time of diagnosis of CD was 43 years. Mean duration of CD until diagnosis of cancer was 14 years. Only five patients were diagnosed for cancer preoperatively. Staging revealed advanced tumors in almost all patients. Mean survival after surgery was 29 months (2-149 months).

CONCLUSIONS

Cancer risk in CD and especially in Crohn's colitis may still be underestimated. Delayed diagnosis resulted in a poor prognosis. The value of colonoscopy as surveillance tool is questioned by the fact that in our patients, carcinoma was diagnosed in some patients preoperatively by routine colonoscopy. Therefore, additional markers should be identified to detect CD patients at risk.

Meta-analysis of risk of malignancy with immunosuppressive drugs in inflammatory bowel disease

BACKGROUND

There is a concern as to whether long-term administration of immunosuppressants in patients with inflammatory bowel disease (IBD) would increase the risk of malignancy.

OBJECTIVE

To compare the risks of developing malignancy between patients with IBD treated with immunosuppressive agents and patients with IBD not receiving these agents.

METHODS

A systematic literature review was conducted, and a meta-analysis was performed on data retrieved from cohort studies that followed patients with IBD who received immunosuppressive agents for more than a year and documented the incidence of newly developed malignancy. An electronic search was conducted using MEDLINE (1966-September 2006), the Cochrane Library (issue 3, 2006), and Japana Centra Revuo Medicina (1981-September 2006). Medical subject headings used in the searches were azathioprine, 6-mercaptopurine, cyclosporine, methotrexate, tacrolimus, inflammatory bowel disease, and neoplasms. We imposed no language limitation in the searches. Additionally, a manual search of reference listings from all articles retrieved from the electronic databases was performed. Using data obtained from control groups or population-based studies, the incidence of newly developed malignancy in patients with IBD treated with immunosuppressive agents was compared with that of patients with IBD who were not receiving immunosuppressive agents. Statistical analysis for the change in risk of developing malignancy was performed using the weighted mean difference (WMD) normalized to per person-year and its 95% confidence interval.

RESULTS

Nine cohort studies met the inclusion criteria for this meta-analysis. Analysis of these studies showed no discernible difference (WMD -0.3 x 10(-3)/person-year; 95% CI -1.2 x 10(-3) to 0.7 x 10(-3)) in the incidence of any kind of malignancy in patients with IBD who received immunosuppressants compared with those who did not receive immunosuppressants. No significant difference in WMD was observed when the data from patients with either Crohn's disease (CD) or ulcerative colitis (UC) were analyzed separately.

CONCLUSIONS

Our findings suggest that the administration of immunosuppressive agents in patients with either CD or UC probably does not confer a significantly increased risk of malignancy compared with patients with IBD who are not receiving these agents.

Beyond foreign-body-induced carcinogenesis: Impact of reactive oxygen species derived from inflammatory cells in tumorigenic conversion and tumor progression

Foreign-body-induced carcinogenesis is a traditional, maybe old, way of understanding cancer development. A number of novel approaches are available today to elucidate cancer development. However, there are things we learn from the old, and thus I bring out some examples of various clinical cases and experimental models of foreign-body-induced tumorigenesis. What is notable is that the foreign bodies themselves are unrelated to each other, whereas commonly underlying in them is to induce inflammatory reaction, especially stromal proliferation, where those exogenous materials are incorporated and undigested. Such foreign-body-induced carcinogenesis is also recognized in the step of tumor progression, the final step of carcinogenesis that tumor cells acquire malignant phenotypes including metastatic properties. And the phenomenon is universally observed in several cell lines of different origins. In this review I would like to show the evidence that tumor development and progression are accelerated inevitably by inflammation caused from foreign bodies, and that reactive oxygen species derived from inflammatory cells are one of the most important genotoxic mediators to accelerate the process.

Survival after colorectal cancer in patients with Crohn's disease: A nationwide population-based Danish follow-up study

BACKGROUND AND AIMS

Patients with Crohn's disease (CD) are at increased risk of colorectal cancer (CRC), but little is known about the impact of CD on CRC prognosis. Based on nationwide population-based registries, we compared survival among CRC patients with CD and CRC patients without CD.

METHODS

We used the Danish Cancer Registry and the Danish Hospital Discharge Registry to identify all patients diagnosed with CRC, with and without CD, in Denmark between 1977 and 1999. We ascertained the stage distribution at the time of CRC diagnosis and 1- and 5-yr survival both for patients with Crohn-associated CRC and patients with non-Crohn CRC. Cox regression was used to compute hazard ratios (HRs), adjusting for gender, age, calendar year, and stage.

RESULTS

We identified 100 CRC patients with CD and 71,438 CRC patients without CD. At the time of diagnosis, patients with CD were younger, but stage distributions were similar in the two groups. The overall HR for CRC with CD compared to CRC without CD was 1.82 (95% CI 1.36-2.43) after 1 yr of follow-up, and 1.57 (95% CI 1.24-1.99) after 5 yr of follow-up. Subanalyses showed that the effect of CD on CRC survival was more pronounced in the youngest patients (0-59 yr), in men, and in patients whose tumors had regional spread.

CONCLUSIONS

We found that CD worsens the prognosis of CRC, particularly CRC with regional spread.

Enhanced expression of MMP-7 and MMP-13 in inflammatory bowel disease: a precancerous potential?

Matrix metalloproteinases (MMPs) are responsible for the turnover and degradation of extracellular matrix. They play a crucial role in the growth and migration of colorectal carcinoma cells. Colorectal carcinomas are characterized by enhanced expression of MMP-2, MMP-9, MMP-7, and MMP-13. The aim of this study was to determine the expression levels of MMP-2, MMP-9, MMP-7, MMP-13, and MMP-14 and their specific inhibitor TIMP-1 in inflammatory bowel diseases and precancerous lesions of the colon, i.e., Crohn's disease and ulcerative colitis, and in adenomatous polyps (APs) for comparison. Biopsy samples of pathological and healthy tissue were obtained from 40 patients with inflammatory bowel disease (ulcerative colitis, n = 17; Crohn's disease, n = 23) and from 19 patients with APs. mRNA was measured by quantitative real-time polymerase chain reaction to study MMP and TIMP-1 gene expression in both pathological and normal mucosal specimens. For MMP-2, MMP-9, and TIMP-1, protein expression also was quantified with sandwich enzyme-linked immunosorbent assay. In biopsy specimens of Crohn's disease and ulcerative colitis, significantly increased levels of MMP-2, MMP-7, and MMP-13 mRNA were found. MMP-2 and MMP-9 showed enhanced secretion on the protein level. AP revealed an increased transcription of MMP-7 and MMP-13 genes. MMP-14 mRNA was decreased in APs. MMPs, especially MMP-7 and MMP-13, which are expressed primarily on the tumor cell surface, are elevated in inflammatory bowel disease, which may have more chance to evolve into malignancy than normal tissue. In APs, increased expression of MMP-7 and MMP-13 may serve as an early indicator for colorectal carcinogenesis.

Low-dose rate prostate brachytherapy is well tolerated in patients with a history of inflammatory bowel disease

PURPOSE

We report on the follow-up of 24 patients with a prior history of inflammatory bowel disease (IBD) treated with brachytherapy for early-stage prostate cancer.

METHODS AND MATERIALS

Twenty-four patients with a history of inflammatory bowel disease (17 with ulcerative colitis (UC), 7 with Crohn's disease [CD]) underwent prostate brachytherapy between 1992 and 2004. Fifteen patients were treated with I-125 implantation and 6 patients were treated with Pd-103 alone or in combination with 45 Gy external beam radiation. Charts were reviewed for all patients, and all living patients were contacted by phone. National Cancer Institute common toxicity scores for proctitis were assigned to all patients. Actuarial risk of late toxicity was calculated by the Kaplan-Meier method. Statistical analysis was performed using SPSS software. Follow-up ranged from 3 to 126 months (median, 48.5 months; mean, 56.8 months).

RESULTS

None of the patients experienced Grade 3 or 4 rectal toxicity. Four patients experienced Grade 2 late rectal toxicity. The 5-year actuarial freedom from developing late Grade 2 rectal toxicity was 81%. At a median follow-up of 48.5 months, 23 patients were alive and had no evidence of disease with a median prostate-specific antigen for the sample of 0.1 ng/mL (range, <0.05-0.88 ng/mL). One patient died of other causes unrelated to his prostate cancer.

CONCLUSIONS

Prostate brachytherapy is well tolerated in patients with a history of controlled IBD. Therefore, brachytherapy should be considered a viable therapeutic option in this patient population.

Cancer in Crohn's disease

There has been a multitude of case reports, case series, hospital-based, and population-based studies that link CD to various types of cancers. When each of these studies is scrutinized, however, there is only enough evidence to support a link between colorectal adenocarcinoma, SBA, and squamous and adenocarcinomas that are associated with perianal fistulizing disease. All of the studies of large bowel adenocarcinoma or SBA follow patients in an era during which there were far fewer effective medicines to treat CD and surgery was more commonplace. The only surveillance study of patients who had extensive, long-duration Crohn's colitis showed a 22% risk for developing neoplasia (low-grade, high-grade, or cancer) after four surveillance examinations. Overall results from this study and the multitude of the other studies show that the risk for cancer in Crohn's colitis is equal to that in UC given equal extent and duration of disease. Patients who have Crohn's colitis that affects at least one third of the colon and with at least 8 years of disease should undergo screening and surveillance, just as in UC. Although the absolute risk for SBA in CD is low (2.2% at 25 years in one study), we should not rule out screening and surveying for this complication that is associated with significant morbidity and mortality in patients who have long-standing, extensive, small bowel disease. The risk for lymphoma and leukemia in CD is low, but immunomodulators and biologics may increase this risk. The evidence that links carcinoid tumors to CD is weak, and population-based studies need to be done. The study of cancers that are associated with CD is an evolving field that surely will change given that immunomodulators and biologics are being used with greater frequency.

Pathology of dysplasia and cancer in inflammatory bowel disease

Morphologic identification of dysplasia in mucosal biopsies is the best and most reliable marker of an increased risk for malignancy in patients who have inflammatory bowel disease, and it forms the basis of the recommended endoscopic surveillance strategies that are in practice for patients who have this illness. In ulcerative colitis (UC) and Crohn's disease (CD), dysplasia is defined as unequivocal neoplastic epithelium that is confined to the basement membrane, without invasion into the lamina propria. Unfortunately, unlike in UC, only a few studies have evaluated the pathologic features and biologic characteristics of dysplasia and carcinoma in CD specifically. As a result, this article focuses mainly on the pathologic features, adjunctive diagnostic methods, and differential diagnosis of dysplasia in UC.

Cell differentiation dependent expressed CCR6 mediates ERK-1/2, SAPK/JNK, and Akt signaling resulting in proliferation and migration of colorectal cancer cells

The expression of CCL20 (MIP-3alpha), which chemoattracts leukocytes to sites of inflammation, has been shown in intestinal epithelial cells (IEC). Aim of this study was to analyze the role of the CCL20 receptor CCR6 in IEC and colorectal cancer (CRC) cells. Expression of CCR6 and CCL20 was analyzed by RT-PCR and immunohistochemistry. Signaling was investigated by Western blotting, proliferation by MTS assays and chemotactic cell migration by wounding assays. The effect of CCL20 on Fas-induced apoptosis was determined by flow cytometry. CCR6 and its ligand CCL20 are expressed in IEC. Moreover, CRC and CRC metastases express CCR6, which is upregulated during IEC differentiation. Stimulation of IEC with CCL20 and proinflammatory stimuli (TNF-alpha, IL-1beta, LPS) significantly upregulates CCL20 mRNA expression. CCL20 expression was significantly increased in inflamed colonic lesions in Crohn's disease and correlated significantly with the IL-8 mRNA expression in these lesions (r = 0.71) but was downregulated in CRC metastases. CCL20 activated Akt, ERK-1/2, and SAPK/JNK MAP kinases and increased IL-8 protein expression. The CCL20 mediated activation of these pathways resulted in a 2.6-fold increase of cell migration (P = 0.001) and in a significant increase of cell proliferation (P < 0.05) but did not influence Fas-induced apoptosis. In conclusion, IEC and CRC express CCL20 and its receptor CCR6. CCL20 expression is increased in intestinal inflammation, while CCR6 is upregulated during cell differentiation. CCR6 mediated signals result in increased IEC migration and proliferation suggesting an important role in intestinal homeostasis and intestinal inflammation by mediating chemotaxis of IEC but also in mediating migration of CRC cells.

Crohn's colitis: the incidence of dysplasia and adenocarcinoma in surgical patients

PURPOSE

Data supporting an increased risk of colorectal cancer in patients with Crohn's colitis are inconsistent. Despite this, clinical recommendations regarding colonoscopic screening and surveillance for patients with Crohn's colitis are extrapolated from chronic ulcerative colitis protocols. The primary aim of our study was to determine the incidence of dysplasia and carcinoma in pathology specimens of patients undergoing segmental or total colectomy for Crohn's disease of the large bowel. In addition, we sought to identify risk factors associated with the development of dysplasia and carcinoma.

METHODS

We performed a retrospective review of all patients operated on at our institution for Crohn's colitis between January 1992 and May 2004. Data were retrieved from patient charts, operative notes, and pathology reports. Logistic regression was used to model the probability of having dysplasia or adenocarcinoma.

RESULTS

Two hundred twenty-two patients (138 females) who underwent surgical resection for the treatment of Crohn's colitis were included in the study. Mean age at surgery was 41 (range, 15-82) years and the mean duration of disease was 10 (range, 0-53) years. There were five cases of dysplasia (2.3 percent) and six cases of adenocarcinoma (2.7 percent). Three patients with dysplasia and one with adenocarcinoma were diagnosed on preoperative colonoscopy; while the other cases were discovered incidentally on pathologic examination of resected specimens. Factors associated with the presence of dysplasia or adenocarcinoma included older age at diagnosis (38.2 vs. 30.3 years, P = 0.02), longer disease duration (16.0 vs. 10.1 years, P = 0.05), and disease extent (90 percent extensive vs. 59 percent limited, P = 0.05).

CONCLUSIONS

Patients with severe Crohn's colitis requiring surgery are at significant risk for developing dysplasia and adenocarcinoma, particularly when diagnosed at an older age, after longer disease duration, and with more extensive colon involvement.

Survival after colorectal cancer in patients with ulcerative colitis: a nationwide population-based Danish study

OBJECTIVES

Patients with ulcerative colitis (UC) are at increased risk of colorectal cancer (CRC). Little is known about how UC impacts CRC prognosis. In a nationwide population-based study we examined the CRC prognosis in UC patients compared to CRC patients without UC.

METHODS

From the Danish Cancer Registry and the Danish Hospital Discharge Registry, we identified all CRC patients and all patients with UC in Denmark from 1977 to 1999. We compared survival in 279 UC patients with CRC to all other 71,259 CRC patients and computed mortality rate ratios (MRR). We also compared stage distribution at time of cancer diagnosis.

RESULTS

The mean age at time of CRC diagnosis was 62.6 yr in UC patients and 71.2 yr in patients without UC. Cancer stage distribution for localized cancer, regional spread, and distant metastasis were 46.6%, 30.1%, and 16.5% in UC patients compared to 44.0%, 28.3%, and 19.4% in CRC patients without UC. The overall MRR for UC patients with CRC compared with all other CRC patients were 1.24 (95% CI 1.02-1.51) in the first year and 1.17 (95% CI 1.01-1.36) after 5 yr of follow-up.

CONCLUSION

UC patients with CRC have a stage distribution similar to patients with CRC without UC. The prognosis of CRC is poorer for UC patients than for patients without UC.

Epstein-Barr virus, cytokines, and inflammation: a cocktail for the pathogenesis of Hodgkin's lymphoma?

The association between chronic inflammation and cancer has been known for well over a century. However, direct evidence detailing the role of inflammation in carcinogenesis has been slow in forthcoming. A number of recent studies suggest that the gaps in our understanding of the molecular pathways bridging the link between inflammation and cancer are slowly beginning to close and that this relationship is more deep-rooted than had been previously believed. This review addresses the link between inflammation and Hodgkin's lymphoma (HL), a malignancy which has many features reminiscent of chronic inflammation. The role of Epstein-Barr virus (EBV) in the pathogenesis of HL is discussed, along with an outline of our current understanding of the cellular nature and development of Reed-Sternberg cells, the malignant cells of HL. The involvement of cytokines and chemokines as orchestrators of inflammation and vehicles for chemical cross-talk between the malignant cells and the reactive inflammatory infiltrate forms a major part of the review. It is suggested that chronic inflammation, triggered by factors such as EBV, is likely to contribute to tumor cell proliferation, progression, and inhibition of apoptosis. Furthermore, it is proposed that the pro-inflammatory transcription factor NF-kappaB plays a central role in many of these processes.

Oxidative and nitrative DNA damage as biomarker for carcinogenesis with special reference to inflammation

Reactive oxygen and nitrogen species are known to participate in a wide variety of human diseases. Oxidative DNAdamage is involved in chemical carcinogenesis and aging. Monocyclic chemicals induce mainly oxidative DNAdamage, whereas polycyclic chemicals can induce oxidative DNA damage in addition to DNA adduct formation. Recently, chronic infection and inflammation have been recognized as important factors for carcinogenesis. Nitrative DNA damage as well as oxidative DNA damage is induced in relation to inflammationrelated carcinogenesis. The authors examined the formation of 8-nitroguanine, a nitrative DNA lesion, in humans and animals under inflammatory conditions. An immunofluorescence labeling study demonstrated that 8-nitroguanine was strongly formed in gastric gland epithelial cells in gastritis patients with H. pylori infection, in hepatocytes in patients with hepatitis C, and in oral epithelium of patients with oral lichen planus. 8-Nitroguanine was also formed in colonic epithelial cells of model mice of inflammatory bowel diseases and patients with ulcerative colitis. Interestingly, 8-nitroguanine was formed at the sites of carcinogenesis regardless of etiology. Therefore, 8-nitroguanine could be used as a potential biomarker to evaluate the risk of inflammation- related carcinogenesis.

Salicylate modulates oxidative stress in the rat colon: a proteomic approach

The dietary phenolic compound, salicylic acid, decreases oxidative stress and pro-inflammatory and potentially neo-plastic prostaglandins with a concomitant increase in glutathione peroxidase activity. Salicylic acid, a dietary plant-based phenolic compound and also the main metabolite of aspirin, may contribute to the colon protective effects of plant-based diets. Oxidative stress is a characteristic of pre-cancerous and cancerous colon and inflammatory bowel diseases (IBD) that increase colon cancer risk. The mechanism(s) whereby salicylic acid modulates potentially pro-cancerous activity associated with oxidative stress is further investigated here using a proteomic approach. A rat model of oxidative stress was supplemented with salicylic acid (1 mg/kg diet, mean plasma levels 310+/-32 micromol/l). Soluble colon protein extracts were subjected to 2D PAGE. Salicylic acid modulated proteins, identified using MALDI-TOF and LC/MS/MS, are involved in protein folding, transport, redox, energy metabolism and cytoskeletal regulation. A partial least squares (PLS) analysis approach was used to assist biological interpretation of the altered protein profiles via their associations between previously published biochemical measurements of oxidative stress, prostaglandin levels and increased glutathione peroxidase activity. Early detection of altered homeostasis in colon may assist in identifying pre-pathological features preceding colon tumorigenesis and contribute to an understanding of epidemiological evidence supporting a protective effect of plant-based diets.

Strategies for detecting colon cancer and/or dysplasia in patients with inflammatory bowel disease

BACKGROUND

Patients with longstanding ulcerative colitis and colonic Crohn's disease have an increased risk of colorectal cancer compared with the general population. This review assesses the evidence that endoscopic surveillance may prolong life by allowing earlier detection of colon cancer or its pre-cursor lesion, dysplasia, in patients with inflammatory bowel disease.

OBJECTIVES

To assess the effectiveness of cancer surveillance programs in reducing the death rate from colorectal cancer in patients with ulcerative colitis and colonic Crohn's disease.

SEARCH STRATEGY

The following strategies were used to identify relevant studies:1. MEDLINE and the Cochrane Central Register of Controlled Trials were searched from 1966 to August 2005. The medical subject headings "Ulcerative Colitis", "Crohn Disease" or "Inflammatory Bowel Disease" and "Surveillance" or "Cancer" were used to perform key-word searches of the databases.2. Hand searching of reference lists from papers.

SELECTION CRITERIA

Potentially relevant articles were reviewed independently and unblinded by three authors to determine if they fulfilled the selection criteria. Each article was rated as being eligible, ineligible, or without sufficient information to determine eligibility. Any disagreement between reviewers was resolved by consensus. Any trials published in abstract form were only considered if it was possible to obtain full details of the protocol and results from the authors.

DATA COLLECTION AND ANALYSIS

Eligible articles were reviewed in duplicate and the results of the primary research trials were abstracted onto specially designed data extraction forms. The proportion of patients dying from bowel cancer or other causes in the control and surveillance groups of each study was derived from life tables, survival curves or where possible, by calculating life tables from the data provided. Data from the original research articles were converted into 2x2 tables (survival versus death x surveillance versus control) for each of the individual studies for comparable follow-up intervals. The presence of significant heterogeneity among studies was tested by the chi-square test. Because this is a relatively insensitive test, a P value of less than 0.1 was considered statistically significant. Provided statistical heterogeneity was not present, the fixed effects model was used for the pooling of data. The 2x2 tables were combined into a summary test statistic using the pooled relative risk (RR) and 95% confidence intervals as described by Cochrane and Mantel and Haenszel.

MAIN RESULTS

Karlen 1998a in a nested case-control study comprising 142 patients from a study population of 4664 UC patients, found that 2/40 patients dying of colorectal cancer had undergone surveillance colonoscopy on at least one occasion compared with 18/102 controls (RR 0.28, 95% CI 0.07 to 1.17). One of 40 patients who died from colorectal cancer had undergone surveillance colonoscopies on two or more occasions compared with 12/102 controls (RR 0.22, 95% CI 0.03 to 1.74) in contrast to a more modest effect observed for patients who had only one colonoscopy (RR 0.43, 95% CI 0.05 to 3.76). Choi 1993 found that carcinoma was detected at a significantly earlier stage in the surveilled patients; 15/19 had Duke's A or B carcinoma in the surveilled group compared to 9/22 in the non-surveilled group (P = 0.039). The 5-year survival rate was 77.2% for cancers occurring in the surveillance group and 36.3% for the no-surveillance group (P = 0.026). Four of 19 patients in the surveillance group died from colorectal cancer compared to 11 of 22 patients in the non-surveillance group (RR 0.42, 95% CI 0.16 to 1.11). Lashner 1990 found that four of 91 patients in a surveillance group died from colorectal cancer compared to 2 of 95 patients in a non-surveilled group (RR 2.09, 95% CI 0.39 to 11.12). Colectomy was less common in the surveillance group, 33 compared to 51 (P < 0.05) and was performed four years later (after 10 years of disease) in the surveillance group. For the pooled data analysis 8/110 patients in the surveillance group died from colorectal cancer compared to 13/117 patients in the non-surveillance group (RR 0.81, 95% CI 0.17 to 3.83).

AUTHORS' CONCLUSIONS

There is no clear evidence that surveillance colonoscopy prolongs survival in patients with extensive colitis. There is evidence that cancers tend to be detected at an earlier stage in patients who are undergoing surveillance, and these patients have a correspondingly better prognosis, but lead-time bias could contribute substantially to this apparent benefit. There is indirect evidence that surveillance is likely to be effective at reducing the risk of death from IBD-associated colorectal cancer and indirect evidence that it may be acceptably cost-effective.

Bacteria and cancer: cause, coincidence or cure? A review

Research has found that certain bacteria are associated with human cancers. Their role, however, is still unclear. Convincing evidence links some species to carcinogenesis while others appear promising in the diagnosis, prevention or treatment of cancers. The complex relationship between bacteria and humans is demonstrated by Helicobacter pylori and Salmonella typhi infections. Research has shown that H. pylori can cause gastric cancer or MALT lymphoma in some individuals. In contrast, exposure to H. pylori appears to reduce the risk of esophageal cancer in others. Salmonella typhi infection has been associated with the development of gallbladder cancer; however S. typhi is a promising carrier of therapeutic agents for melanoma, colon and bladder cancers. Thus bacterial species and their roles in particular cancers appear to differ among different individuals. Many species, however, share an important characteristic: highly site-specific colonization. This critical factor may lead to the development of non-invasive diagnostic tests, innovative treatments and cancer vaccines.