Risk of ulcerative colitis-associated colorectal cancer in China: a multi-center retrospective study

Update and latest advances in mechanisms and management of colitis-associated colorectal cancer

Colitis-associated colorectal cancer (CAC) is defined as a specific cluster of colorectal cancers that develop as a result of prolonged colitis in patients with inflammatory bowel disease (IBD). Patients with IBD, including ulcerative colitis and Crohn's disease, are known to have an increased risk of developing CAC. Although the incidence of CAC has significantly decreased over the past few decades, individuals with CAC have increased mortality compared to individuals with sporadic colorectal cancer, and the incidence of CAC increases with duration. Chronic inflammation is generally recognized as a major contributor to the pathogenesis of CAC. CAC has been shown to progress from colitis to dysplasia and finally to carcinoma. Accumulating evidence suggests that multiple immune-mediated pathways, DNA damage pathways, and pathogens are involved in the pathogenesis of CAC. Over the past decade, there has been an increasing effort to develop clinical approaches that could help improve outcomes for CAC patients. Colonoscopic surveillance plays an important role in reducing the risk of advanced and interval cancers. It is generally recommended that CAC patients undergo endoscopic removal or colectomy. This review summarizes the current understanding of CAC, particularly its epidemiology, mechanisms, and management. It focuses on the mechanisms that contribute to the development of CAC, covering advances in genomics, immunology, and the microbiome; presents evidence for management strategies, including endoscopy and colectomy; and discusses new strategies to interfere with the process and development of CAC. These scientific findings will pave the way for the management of CAC in the near future.

Recent advances in surveillance colonoscopy for dysplasia in inflammatory bowel disease

Inflammatory bowel disease (IBD) has a global presence with rapidly increasing incidence and prevalence. Patients with IBD including those with ulcerative colitis and Crohn's disease have a higher risk of developing colorectal cancer (CRC) compared to the general population. Risk factors for CRC in patients with IBD include long disease duration, extensive colitis, primary sclerosing cholangitis, family history of CRC, stricture, and prior dysplasia. Surveillance colonoscopy for CRC in patients with IBD should be tailored to individualized risk factors and requires careful monitoring every year to every five years. The current surveillance techniques are based on several guidelines. Chromoendoscopy with targeted biopsy is being recommended increasingly, and high-definition colonoscopy is gradually replacing standard-definition colonoscopy. However, it remains unclear whether chromoendoscopy, virtual chromoendoscopy, or white-light endoscopy has better efficiency when a high-definition scope is used. With the development of new endoscopic instruments and techniques, the paradigm of surveillance strategy has gradually changed. In this review, we discuss cutting-edge surveillance colonoscopy in patients with IBD including a review of literature.

Identification of hub genes and pathways in colitis-associated colon cancer by integrated bioinformatic analysis

Background

Colitis-associated colon cancer (CAC) patients have a younger age of onset, more multiple lesions and invasive tumors than sporadic colon cancer patients. Early detection of CAC using endoscopy is challenging, and the incidence of septal colon cancer remains high. Therefore, identifying biomarkers that can predict the tumorigenesis of CAC is in urgent need.

Results

A total of 275 DEGs were identified in CAC. IGF1, BMP4, SPP1, APOB, CCND1, CD44, PTGS2, CFTR, BMP2, KLF4, and TLR2 were identified as hub DEGs, which were significantly enriched in the PI3K-Akt pathway, stem cell pluripotency regulation, focal adhesion, Hippo signaling, and AMPK signaling pathways. Sankey diagram showed that the genes of both the PI3K-AKT signaling and focal adhesion pathways were upregulated (e.g., SPP1, CD44, TLR2, CCND1, and IGF1), and upregulated genes were predicted to be regulated by the crucial miRNAs: hsa-mir-16-5p, hsa-mir-1-3p, et al. Hub gene-TFs network revealed FOXC1 as a core transcription factor. In ulcerative colitis (UC) patients, KLF4, CFTR, BMP2, TLR2 showed significantly lower expression in UC-associated cancer. BMP4 and IGF1 showed higher expression in UC-Ca compared to nonneoplastic mucosa. Survival analysis showed that the differential expression of SPP1, CFRT, and KLF4 were associated with poor prognosis in colon cancer.

Conclusion

Our study provides novel insights into the mechanism underlying the development of CAC. The hub genes and signaling pathways may contribute to the prevention, diagnosis and treatment of CAC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12863-022-01065-7.

From inflammatory bowel disease to colorectal cancer: what's the role of miRNAs?

Inflammatory Bowel Disease (IBD) is a chronic inflammatory disease with relapse and remission periods. Ulcerative colitis and Crohn's disease are two major forms of the disease. IBD imposes a lot of sufferings on the patient and has many consequences; however, the most important is the increased risk of colorectal cancer, especially in patients with Ulcerative colitis. This risk is increased with increasing the duration of disease, thus preventing the progression of IBD to cancer is very important. Therefore, it is necessary to know the details of events contributed to the progression of IBD to cancer. In recent years, the importance of miRNAs as small molecules with 20-22 nucleotides has been recognized in pathophysiology of many diseases, in which IBD and colorectal cancer have not been excluded. As a result, the effectiveness of these small molecules as therapeutic target is hopefully confirmed. This paper has reviewed the related studies and findings about the role of miRNAs in the course of events that promote the progression of IBD to colorectal carcinoma, as well as a review about the effectiveness of some of these miRNAs as therapeutic targets.

The Effects of Sishen Wan on T Cell Responses in Mice Models of Ulcerative Colitis Induced by Dextran Sodium Sulfate

Currently, it is unclear whether Sishen Wan (SSW) could modulate the balance of Th1 cells, Th17 cells, and Tregs and we evaluated the effects of SSW on T cell responses in mice models of ulcerative colitis (UC). The mice models of acute UC (4% dextran sodium sulfate (DSS), 8 days) and chronic UC (3% DSS, 16 days) with SSW were assayed. Colon tissues were collected for immunohistochemical analysis, enzyme linked immunosorbent assay (ELISA), and flow cytometry (FCM). The expressions of cytokines associated with Tregs, transcription factors of Th17 cells, the frequencies of Th1 cells, Th17 cells, and Tregs, and the functional plasticity of Th17 cells were detected. The frequency of IFN-γ⁺ T cells was not changed significantly with SSW treatment in acute DSS. In chronic models, the frequency of IFN-γ⁺ T cells was downregulated with SSW. Meanwhile, the levels of RORγt and the frequency of IL-17A⁺ Th17 cells showed no significant differences after SSW treatment. Despite no significant effect on the transdifferentiation of Th17 cells in chronic UC models, SSW transdifferentiated Th17 cells into IL-10⁺ Th17 cells and downregulated IFN-γ⁺ Th17 cells/IL-10⁺ Th17 cells in acute DSS. Moreover, there were no significant changes of cytokines secreted by Tregs in acute DSS after SSW treatment, but SSW facilitated the expressions of IL-10 and IL-35, as well as development of IL-10⁺ Tregs in chronic DSS. SSW showed depressive effects on the immunoreaction of Th17 cells and might promote the conversion of Th17 cells into IL-10⁺ Th17 cells in acute UC, while it inhibited the excessive reaction of Th1 cells, facilitated the development of Tregs, and enhanced the anti-inflammatory effects in chronic UC.

Differential effects of EPA and DHA on DSS-induced colitis in mice and possible mechanisms involved

BACKGROUND

The anti-inflammatory effect of n-3 PUFAs has been widely documented. Emerging evidence suggests that the main component of n-3 PUFAs, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), may have differential effects in ulcerative colitis (UC). It was aimed to clarify their differential effects in UC.

METHODS

Eight-week-old male C57BL/6J mice were randomly divided into 7 groups, namely control, UC model, salicylazosulfapyridine (SASP), low-dose DHA, high-dose DHA, low-dose EPA, and high-dose EPA. DHA, EPA and SASP treatment groups were orally treated accordingly for 9 weeks. During the 5th to 9th week the control group was given distilled water, while other groups were given distilled water with 2% dextran sodium sulfate (DSS) to induce UC. Body weight loss, diarrhea, and stool bleeding were recorded to calculate the disease activity index (DAI). The level of tight junction proteins Claudin-1 and Occludin, and cytokines including TNF-α, IL-6, and IL-1β as well as inflammatory cell markers such as MPO, F4/80, and MCP-1 in the intestinal epithelium were measured using western blotting. Activation of IL-6/STAT3 and NLRP3/IL-1β inflammatory pathways was also assessed. Levels of proliferation-related proteins of the Wnt/β-catenin pathway with c-myc, Cyclin-D1, and PCNA were detected.

RESULTS

EPA, superior to DHA, significantly attenuated DSS-induced colitis evidenced by reduced DAI scores, cytokine production and inflammatory cell infiltration. Mechanically, EPA triggered a marked up-regulation of Claudin-1 and Occludin with down-regulation of their up-stream Akt and ERK. EPA also inhibited NLRP3/IL-1β and IL-6/STAT3 inflammatory pathways and up-regulated the Wnt/β-catenin pathway.

CONCLUSIONS

EPA is more suitable to be used for the treatment of UC than DHA.

Oral Nanoparticles of SNX10-shRNA Plasmids Ameliorate Mouse Colitis

Background

Our previous study found that deletion of Sorting nexin 10 (SNX10) can protect against colonic inflammation and pathological damage induced by dextran sulfate sodium (DSS). This inspired us that modulation of SNX10 expression in colonic epithelial cells might represent a promising therapeutic strategy for inflammatory bowel disease (IBD).

Methods

Effective delivery of siRNA/shRNA to silence genes is a highly sought-after means in the treatment of multiple diseases. Here, we encapsulated SNX10-shRNA plasmids (SRP) with polylactide-polyglycolide (PLGA) to make oral nanoparticles (NPs), and then applied them to acute and chronic IBD mice model, respectively. The characteristics of the nanoparticles were assayed and the effects of SRP-NPs on mouse IBD were evaluated.

Results

High-efficiency SNX10-shRNA plasmids were successfully constructed and coated with PLGA to obtain nanoparticles, with a particle size of 275.2 ± 11.4mm, uniform PDI distribution, entrapment efficiency of 87.6 ± 2.5%, and drug loading of 13.11 ± 1.38%, displayed dominant efficiency of SNX10 RNA interference in the colon. In both acute and chronic IBD models, SRP-NPs could effectively reduce the loss of mice body weight, relieve the intestinal mucosal damage and inflammatory infiltration, inhibit the expression of inflammatory cytokines IL-1β, IL-23, TNF-α, and down-regulate the expression of toll-like receptors (TLRs) 2 and 4.

Conclusion

Oral nanoparticles of SNX10-shRNA plasmid displayed dominant efficiency of SNX10 RNA interference in the colon and ameliorate mouse colitis via TLR signaling pathway. SNX10 is a new target for IBD treatment and nanoparticles of SNX10-shRNA plasmid might be a promising treatment option for IBD.

Chromoendoscopy with targeted biopsies is superior to white-light endoscopy for the long-term follow-up detection of dysplasia in ulcerative colitis patients: a multicenter randomized-controlled trial

Background

Data from single-center experience or small sample-sized studies have shown that chromoendoscopy (CE) might be superior to white-light endoscopy (WLE) for dysplasia surveillance in ulcerative colitis (UC) patients. We performed a prospective randomized trial with a long-term follow-up to compare the detection rate of dysplasia among WLE with targeted biopsies (WLT), WLE with random biopsies (WLR), and dye-based CE with targeted biopsies (CET) in UC patients.

Methods

Patients with long-standing UC were enrolled from 11 medical centers from March 2012 to December 2013 and randomized into three arms (WLT, WLR, and CET). Only high-definition endoscopy was used in all three groups. The patients were followed up by annual endoscopy with biopsies through December 2017.

Results

With a median follow-up time of 55 months, a total of 122 patients with 447 colonoscopies were finally analysed in the per-protocol set: WLT (n = 43), WLR (n = 40), and CET (n = 39). A total of 34 dysplastic lesions were found in 29 colonoscopies of 21 patients. WLR and CET could identify more colonoscopies that diagnosed dysplasia than WLT (8.1% and 9.7% vs 1.9%; P = 0.014 and 0.004, respectively). WLR obtained more biopsied samples than WLT and CET (16.4 ± 5.1 vs 4.3 ± 1.4 and 4.3 ± 1.4; both P < 0.001). During the second half of the follow-up (37 − 69 months), CET could identify more colonoscopies that diagnosed dysplasia than WLT (13.3% vs 1.6%, P = 0.015) and showed a trend for increasing the detection rate compared with WLR (13.3% vs 4.9%, P = 0.107).

Conclusions

For a better outcome of cancer/dysplasia surveillance in patients with long-standing UC, CET appeared to be more effective than WLT and less tedious than WLR. CET was found to be particularly useful when a long-term (>3 years) follow-up was conducted for dysplasia surveillance. The trial was registered on www.chictr.org.cn (ChiCTR1900023689).

Risk of Colorectal Cancer in Ulcerative Colitis Patients: A Systematic Review and Meta-Analysis

Background

Ulcerative colitis (UC) patients have an increased risk for the development of colorectal cancer (CRC). Our aim was to assess the risk of CRC in UC patients compared with disease extent, disease duration, and geographic variation.

Methods

In this systematic review and meta-analysis, we searched PubMed, scientific meetings, and the bibliographies of identified articles, with English language restrictions for studies published from 1988 to 2018, and assessed the risk of CRC in UC patients. Patients with Crohn's disease, family history of CRC, and colorectal adenomatous polyp (CAP) were excluded from this research. The study was registered with PROSPERO, number CRD42018102213.

Findings

We included 58 studies that included 267566 UC patients. Extensive UC and left-sided UC had a higher risk of CRC than proctitis UC. Geography also played a role in UC-associated CRC development. The time of malignant transformation in Asian UC patients started after 10-20 years of this disease duration. North American UC-associated CRC patients significantly increased in more than 30 years of this disease duration.

Conclusion

In a systematic review of the literature, we found that disease extent, disease duration, and geography were strong, independent risk factors in UC-associated CRC development.

Evidence of Differences and Discrimination in the Delivery of Care: Colorectal Screening in Healthy People and in the Care and Surveillance of Patients with Inflammatory Bowel Disease

Objectives: In this review the management of colorectal disease will be investigated as an exemplar of common practice in the UK in an attempt to identify factors responsible for the more general experiences of patients from ethnic minorities. Within this field such populations have a lower uptake of cancer screening programmes and their experience of day-to-day care for chronic gastrointestinal disorders is poor. Study design: PubMed and Google Scholar were reviewed in 2016 to identify publications concerning colorectal screening in patients with inflammatory bowel disease and healthy communities. Methods: Data were extracted from each paper and the references exploded to identify other potential reports. Results: It is reported that barriers exist both at individual and access levels but little has been done to overcome these. There have been a number of suggestions as to how to provide equitable access, but there is a clear need to ensure that these are evidence based and have been tested and shown to be effective in clinical trials. Conclusions: Clearly, current systems of surveillance and screening will only make a difference if they provide effective and acceptable services to all potential clients. Most programmes fail to address the specific risks and anxieties of minority groups, which are thought to be poorly compliant. This review considers those factors that may play a part and suggests approaches that could overcome these deficiencies. Some clues as to these factors may come from work with patients with chronic disorders.

Association between LINC00657 and miR-106a serum expression levels and susceptibility to colorectal cancer, adenomatous polyposis, and ulcerative colitis in Egyptian population

Colorectal cancer (CRC) represented the second cause of mortality among cancer patients. Long noncoding RNAs and microRNAs (miRNAs) serve as noninvasive biomarkers for CRC surveillance and introduce new therapeutic approaches. LINC00657 and miR-106a expression levels play a pivotal role in CRC. This study included 190 Egyptian subjects, and the expression levels of LINC00657 and miR-106a in serum were measured by using quantitative real-time polymerase chain reaction. We found that upregulation of LINC00657 and downregulation of miR-106a are significantly associated with the development of CRC. Also, a positive correlation was detected between their serum levels. In addition, serum LINC00657 can distinguish adenomatous polyposis (AP) patients and/or ulcerative colitis (UC) patients from controls. Also the miRNA-106a expression level discriminates AP but not UC from healthy individuals. Our study cited new diagnostic biomarkers for CRC, AP, and UC among Egyptians in addition to be noninvasive screening tools for CRC in both healthy subjects and those having precancerous lesions. © 2019 IUBMB Life, 71(9):1322-1335, 2019.

Risk factors for colorectal neoplasia in patients with underlying inflammatory bowel disease: a multicenter study

BACKGROUND

This study sought to evaluate the risk factors for the development of colitis-associated neoplasia (CAN) in Chinese patients with inflammatory bowel disease (IBD).

METHODS

IBD patients who developed CAN between 1999 and 2016 were identified from eight medical centers. In addition to initial pathology evaluation, a CAN diagnosis was confirmed by two expert pathologists. Patients with CAN (n = 29) were compared with non-CAN controls (n = 87). Matching was performed for gender and IBD type with a ratio of three controls to one subject.

RESULTS

Of the 29 patients with CAN, 8 (27.6%) had colorectal cancer (CRC), 20 (69.0%) had a final diagnosis of low-grade dysplasia and 1 (3.4%) had high-grade dysplasia. Multivariate analysis revealed that an older age at the time of IBD diagnosis and a longer IBD duration were independent risk factors for the development of CAN, with odds ratios of 1.09 [95% confidence interval (CI): 1.04-1.14, P < 0.001] and 1.14 (95% CI: 1.03-1.27, P = 0.013), respectively. Comparison between IBD patients with CRC and those with dysplasia indicated that the former were older at the time of IBD diagnosis (P = 0.012) and had longer IBD durations (P = 0.019).

CONCLUSIONS

Older age at the time of IBD diagnosis and longer IBD duration were found to be associated with the development of CAN in IBD patients.

Colorectal cancer prevention in patients with ulcerative colitis

Ulcerative colitis is characterized by chronic inflammation, which may lead to the accumulation of high levels of pro-inflammatory cytokines within the colonic mucosa, and thus to dysplastic lesions and cancer. Although the trend is decreasing, ulcerative colitis patients still have a 2.4 fold higher risk of colorectal cancer compared to the general population. The key task is to control colonic inflammation, and a rapid step-up approach while closely monitoring intestinal inflammation are recommented. Surveillance colonoscopy program demonstrated its efficacy for reducing the incidence of colorectal cancer in ulcerative colitis. The impact of medication on the reduction of colorectal cancer risk was hardly investigated and it remains unclear whether they have intrinsic anti-neoplastic properties or only downregulate inflammatory pathways. Several studies showed a decreased risk of colorectal cancer in ulcerative colitis patients treated with 5-aminosalicylic acid and chemoprevention with mesalamine compounds is currently recommended. The current level of evidence is too low for thiopurines and anti-TNFα agents. Large, prospective cohort studies are ongoing and are likely to bring new findings about the impact of drugs on colorectal cancer risk in the current era of biologics.

Chemopreventive effects of 5-aminosalicylic acid on inflammatory bowel disease-associated colorectal cancer and dysplasia: a systematic review with meta-analysis

Background and Aims

The chemopreventive effect of 5-aminosalicylic acid (5-ASA) in patients with inflammatory bowel disease (IBD) has been widely studied; however, the results remain conflicting. The aim of this study was to systematically review the literature and update evidence concerning effects of 5-ASA on the risk of colorectal cancer (CRC) and dysplasia (Dys) in patients with ulcerative colitis (UC) or Crohn's disease (CD).

Results

5-ASA showed a chemopreventive effect against CRC/Dys in IBD patients (OR = 0.58, 95% CI: 0.45−0.75). However, this effect was significant only in clinical-based studies (OR = 0.51; 95% CI: 0.39−0.65), but not in population-based studies (OR = 0.71; 95% CI: 0.46−1.09). Moreover, this effect was noticeable in patients with UC (OR = 0.46, 95% CI: 0.34−0.61), but not in CD (OR = 0.66, 95% CI: 0.42−1.03), and on the outcome of CRC (OR = 0.54, 95% CI: 0.39−0.74), but not Dys (OR = 0.47; 95% CI: 0.20−1.10). In IBD patients, mesalazine dosage ≥ 1.2 g/day showed greater protective effects against CRC/Dys than dosages < 1.2 g/day. However, Sulphasalazine therapy did not show any noticeable protective function regardless of the dosage administered.

Materials and Methods

We performed a systematic review with a meta-analysis of 26 observational studies involving 15,460 subjects to evaluate the risks of developing CRC and Dys in IBD patients receiving 5-ASA treatment. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for each evaluation index.

Conclusions

5-ASA has a chemopreventive effect on CRC (but not Dys) in IBD patients. Moreover, UC patients can benefit more from 5-ASA than CD patients. Mesalazine maintenance dosage ≥ 1.2 g/day is an effective treatment for reducing CRC risk in IBD patients.

Impact of mucosal inflammation on risk of colorectal neoplasia in patients with ulcerative colitis: a systematic review and meta-analysis

BACKGROUND AND AIMS

Long-standing ulcerative colitis is an established risk factor for colorectal neoplasia. A number of observational studies have suggested that evidence of mucosal inflammation (endoscopic or histologic) is associated with a greater risk for colorectal neoplasia than is mucosal healing. Our goal was to systematically analyze the risk of colorectal neoplasia in patients with ulcerative colitis who have ongoing mucosal inflammation to better inform surveillance strategies.

METHODS

We performed a systematic review and meta-analysis of the effect of endoscopic and/or histologic inflammation on the risk of colorectal neoplasia in cohort and case-control studies. Sensitivity analyses for study setting and case definition were performed.

RESULTS

Six studies met the inclusion criteria, incorporating outcomes in 1443 patients. No study used a single validated measure for mucosal inflammation. The pooled odds ratio for colorectal neoplasia was 3.5 (95% confidence interval [CI], 2.6-4.8; P < .001) in those with any mucosal inflammation and 2.6 (95% CI, 1.5-4.5; P = .01) in those with histologic inflammation, when compared with those with mucosal healing. The overall quality of the studies was good.

CONCLUSION

The presence of objective evidence of mucosal inflammation during follow-up in patients with ulcerative colitis is associated with a greater risk of subsequent colorectal neoplasia than in those with mucosal healing. This risk factor should be considered in guidelines on surveillance intervals for these patients.

Clinical characteristics of ulcerative colitis-related colorectal cancer in Chinese patients

OBJECTIVE

The prevalence of ulcerative colitis (UC) in China has been increasing, together with the incidence of ulcerative colitis-related colorectal cancer (UCRCC). In this study we aimed to investigate the clinical features of UCRCC in Chinese UC patients.

METHODS

Clinical data of patients with UCRCC during January 2003 to December 2016 were retrieved from the Peking Union Medical College Hospital registration database and compared with that of sporadic colorectal cancer (CRC).

RESULTS

During the study period, among the 10 110 patients with CRC 25 were found to have UCRCC, with an average age of 51 years and a median disease duration of 15 years. The cumulative prevalence of UCRCC was 0.25% in all CRC patients, with a significant increase from 2003-2007 to 2013-2016 (P < 0.01). Altogether 14 (56.0%) patients with UCRCC were men, and 5 (20.0%) had a family history of UC or cancer. Four (16.0%) patients had concurrent high-grade intraepithelial neoplasia with variable differentiated adenocarcinoma at other sites and 19 (59.4%) tumors were moderately or poorly differentiated. Twenty-three (92.0%) patients underwent surgery, of whom 10 (40%) were at stage III and IV according to the TNM staging system. Compared with the 10 085 patients with sporadic CRC, UCRCC patients were younger (P < 0.01) and were more likely to have descending colon involvement and multifocal lesions (P < 0.01).

CONCLUSIONS

UCRCC patients have been increasing in recent years. Compared with patients with sporadic CRC, those with UCRCC are younger and are more likely to have descending colon involvement and multifocality.

Cancer Risk in the Early Stages of Inflammatory Bowel Disease in Korean Patients: A Nationwide Population-based Study

BACKGROUND AND AIMS

The association between inflammatory bowel disease [IBD] and cancer remains poorly defined in Asian populations. Therefore, we conducted a nationwide population-based study to determine the cancer risk in Korean patients with IBD.

METHODS

Using the National Health Insurance claims data, we collected data on patients diagnosed with IBD (5595 Crohn's disease [CD] and 10 049 ulcerative colitis [UC]) from 2011 to 2014. Standardized incidence ratios [SIRs] of overall and site-specific cancers in IBD patients in comparison with the general population were calculated.

RESULTS

The overall cancer risk was higher in CD patients [SIR, 2.2; 95% confidence interval, 1.5-3.0 in men and 3.3; 2.4-4.5 in women] and UC patients [1.9; 1.6-2.3 in men and 1.9; 1.5-2.4 in women]. There were significantly increased risks for the following cancers: small bowel cancer [31.2; 3.8-112.8], colorectal cancer [CRC] [3.7; 1.6-7.2] and haematological cancer [4.0; 1.1-10.3] in men with CD; small bowel cancer [61.1; 7.4-220.6], CRC [4.7; 1.5-10.9], liver cancer [15.3; 5.6-33.2], pancreatic cancer [8.6; 1.0-31.0] and haematological cancer [11.0; 3.6-25.7] in women with CD; CRC [2.1; 1.3-3.3] and cancer of the prostate [3.5; 2.1-5.5], brain/central nervous system [6.1; 1.3-17.9] and thyroid [2.2; 1.1-3.9] in men with UC; and CRC [3.0; 1.5-5.3], cancer of the liver [4.4; 1.6-9.7] and cervix uteri [5.7; 2.4-11.1], and haematological cancer [3.5; 1.1-8.1] in women with UC. Women with CD had an increased risk of non-Hodgkin lymphoma [NHL] and leukaemia. Women with UC had an increased risk of NHL.

CONCLUSIONS

Korean patients with IBD are at increased risk for overall, intestinal and haematological cancer.

Long-term follow-up reveals high incidence of colorectal cancer in Indian patients with inflammatory bowel disease

BACKGROUND

As the magnitude of sporadic colorectal cancer (CRC) in India is low, magnitude of CRC in ulcerative colitis (UC) is also considered low. As a result, screening for CRC in UC although advocated may not be followed everywhere. We report our data of UC-related CRC from a low-incidence area of sporadic CRC.

METHODS

A total of 1012 patients with left-sided colitis/pancolitis having more than one full-length colonoscopy performed at least a year after the onset of symptoms were included in retrospective analysis of prospectively maintained case records. In addition, 136 patients with duration of disease >10 years underwent surveillance white-light colonoscopy prospectively during the study period.

RESULTS

A total of 1012 individuals were finally included (6542 person-years of follow-up, 68.5% males, disease duration: 6.4 ± 6.8 years). Twenty (1.97%) patients developed CRC. Two (10%) patients developed CRC during the first decade, 10/20 (50%) during the second and 8/20 (40%) after the second decade of disease. The cumulative risk of developing CRC was 1.5%, 7.2% and 23.6% in the first, second and third decade, respectively. Of 136 high-risk UC cases, five (3.6%) had CRC on screening colonoscopy. Disease duration and increasing age of onset were associated with higher risk of CRC.

CONCLUSIONS

Cumulative risk of CRC in Indian UC patients is as high as 23.6% at 30 years. The risk of CRC increases with increasing age of onset and increasing duration of disease. A low risk of sporadic CRC does not confer a low risk of UC-related CRC, and regular screening is warranted.

Systematic review with meta-analysis: use of 5-aminosalicylates and risk of colorectal neoplasia in patients with inflammatory bowel disease

BACKGROUND

The relationship of 5-aminosalicylates' use with the risk of colorectal neoplasia in patients with inflammatory bowel disease (IBD) has been the focus of a growing body of research.

AIM

To investigate this association through an updated meta-analysis of observational studies.

METHODS

PubMed, Scopus and major conference proceedings were searched up to December 2016. The identified studies were evaluated for publication bias and heterogeneity. Pooled relative risk (RR) estimates were calculated using random-effect models. Detailed subgroup analyses were performed. The GRADE approach was used to assess the quality of evidence.

RESULTS

Thirty-one independent observational studies including 2137 cases of colorectal neoplasia (of which 76% were cancers) were incorporated. Between-study heterogeneity was moderate, while strong suspicion of small-study effects was raised. The overall analysis revealed a protective association between 5-aminosalicylates' use and colorectal neoplasia (RR = 0.57, 95% CI: 0.45-0.71). When the analysis was stratified according to study design and setting, the association was significant in cohort (RR = 0.65, 95% CI: 0.43-0.99; n = 10) and case-control studies (RR = 0.53, 95% CI: 0.40-0.70; n = 21), population-based (RR = 0.70, 95% CI: 0.52-0.94; n = 12) and hospital-based studies (RR = 0.46, 95% CI: 0.34-0.61; n = 19). Exposure to 5-aminosalicylates was protective against cancer (RR = 0.58, 95% CI: 0.45-0.74) and dysplasia (RR = 0.54, 95% CI: 0.35-0.84). The reduction in colorectal neoplasia risk was strong in ulcerative colitis (RR = 0.50, 95% CI: 0.38-0.64), but nonsignificant in Crohn's disease (RR = 0.76, 95% CI: 0.43-1.33). Mesalazine (mesalamine) use was protective (RR = 0.70, 95% CI: 0.51-0.94) with evidence of a dose-effect. The effect of sulfasalazine was marginally nonsignificant (RR = 0.72, 95% CI: 0.51-1.01).

CONCLUSIONS

Our findings support a potential chemopreventive role of 5-aminosalicylates in IBD. Further, high-quality prospective research is warranted.

Risk of colorectal cancer in Asian patients with ulcerative colitis: a systematic review and meta-analysis

BACKGROUND

The increased risk of colorectal cancer in ulcerative colitis is well known. The risk of sporadic colorectal cancer in Asian populations is considered low and risk estimates of colorectal cancer related to ulcerative colitis from Asia vary. This meta-analysis is an Asian perspective on the risk of colorectal cancer related to ulcerative colitis.

METHODS

We searched PubMed and Embase for terms related to colorectal cancer in ulcerative colitis from inception to July 1, 2016. The search for published articles was done by country for all countries in Asia. We included studies with information on the prevalence and cumulative risk of colorectal cancer at various timepoints. A random-effects meta-analysis was done to calculate the pooled prevalence as well as a cumulative risk at 10 years, 20 years, and 30 years of disease.

FINDINGS

Our search identified 2575 articles; of which 44 were eligible for inclusion. Our analysis included a total of 31 287 patients with ulcerative colitis with a total of 293 reported colorectal cancers. Using pooled prevalence estimates from various studies, the overall prevalence was 0·85% (95% CI 0·65-1·04). The risks for colorectal cancer were 0·02% (95% CI 0·00-0·04) at 10 years, 4·81% (3·26-6·36) at 20 years, and 13·91% (7·09-20·72) at 30 years. Subgroup analysis by stratifying the studies according to region or period of the study did not reveal any significant differences.

INTERPRETATION

We found the risk of colorectal cancer in Asian patients with ulcerative colitis was similar to recent estimates in Europe and North America. Adherence to screening is therefore necessary. Larger population-based, prospective studies are required for better estimates of the risk.

FUNDING

Indo-US Science and Technology Forum.

How Does the Epidemiology of Inflammatory Bowel Disease Differ between East and West? A Korean Perspective

Background

Though low compared with those in Western countries, the incidence and prevalence of inflammatory bowel disease (IBD) are rapidly increasing in Asia. If we could understand the differences in IBD epidemiology between Asian and Western countries, we might gain insights into the etiopathogenesis of IBD as well as guidance for personalized therapy.

Summary

In Asia, unlike in the West, Crohn's disease (CD) predominantly occurs in men and involves a high prevalence of perianal fistulas. Moreover, in Korean CD patients, ileocolonic involvement is predominant, whereas isolated colonic involvement is very uncommon. In both ulcerative colitis (UC) and CD, extraintestinal manifestations, such as primary sclerosing cholangitis, as well as a positive family history of IBD are less frequent in Asian patients. However, as the prevalence of IBD rises in Korea, so does the frequency of a positive family history. While the colectomy rate among Korean UC patients is lower, the intestinal resection rate in CD patients is similar in Korea and in the West. Infectious problems that can adversely influence IBD management are usually more common in Asia.

Key Messages

IBD in Asians differs from that in Westerners in many aspects, including demographic and clinical characteristics, prognosis, and associated problems.

Predicting Outcomes to Optimize Disease Management in Inflammatory Bowel Diseases

BACKGROUND AND AIMS

Efforts to slow or prevent the progressive course of inflammatory bowel diseases [IBD] include early and intensive monitoring and treatment of patients at higher risk for complications. It is therefore essential to identify high-risk patients - both at diagnosis and throughout disease course.

METHODS

As a part of an IBD Ahead initiative, we conducted a comprehensive literature review to identify predictors of long-term IBD prognosis and generate draft expert summary statements. Statements were refined at national meetings of IBD experts in 32 countries and were finalized at an international meeting in November 2014.

RESULTS

Patients with Crohn's disease presenting at a young age or with extensive anatomical involvement, deep ulcerations, ileal/ileocolonic involvement, perianal and/or severe rectal disease or penetrating/stenosing behaviour should be regarded as high risk for complications. Patients with ulcerative colitis presenting at young age, with extensive colitis and frequent flare-ups needing steroids or hospitalization present increased risk for colectomy or future hospitalization. Smoking status, concurrent primary sclerosing cholangitis and concurrent infections may impact the course of disease. Current genetic and serological markers lack accuracy for clinical use.

CONCLUSIONS

Simple demographic and clinical features can guide the clinician in identifying patients at higher risk for disease complications at diagnosis and throughout disease course. However, many of these risk factors have been identified retrospectively and lack validation. Appropriately powered prospective studies are required to inform algorithms that can truly predict the risk for disease progression in the individual patient.

Risk factors for developing colorectal cancer in Japanese patients with ulcerative colitis: a retrospective observational study-CAPITAL (Cohort and Practice for IBD total management in Kyoto-Shiga Links) study I

Background and Aims

Patients with ulcerative colitis (UC) are at risk for developing colorectal cancer (CRC), despite the development of new therapeutic agents. Stratification of the individual UC-patient's risk would be helpful to validate the risk factors for CRC. The aim of this study was to evaluate the risk factors for the development of CRC in a large cohort of patients with UC.

Methods

Data were obtained from 12 hospitals in the Kyoto-Shiga region during 2003–2013. We performed a retrospective cohort study of 2137 patients with UC.

Results

In total, 60 lesions of CRC were detected in 43 (2.0%) of 2137 patients. 30 of the 43 patients were male. The median age was 53 years. The median duration of disease was 13 years, and 67.4% of these patients had a disease duration >10 years. Of the 43 patients, 34 (79.1%) had extensive colitis. Primary sclerosing cholangitis was detected in 2 patients (4.7%). The median corticosteroids (CS) dose was 6.4 g, and 4 patients were treated with a total of more than 10 g of CS. 18 of these patients underwent more than 1 year CS treatment. Of all 60 CRC lesions, 43 (71.7%) were located in the distal colon and 35 (58.3%) were of the superficial type. Moreover, the stage of CRC was stage 0 or I in 55.8% of the 43 patients with CRC. Multivariate analysis suggested that extensive colitis could be a risk factor for the development of advanced CRC in patients with UC.

Conclusions

Our findings indicated that male, extensive colitis, long-term duration of UC and family history of CRC, but not concomitant primary sclerosing cholangitis, are important factors for predicting CRC in Japanese patients with UC. Moreover, long-standing extensive colitis might contribute to the progression of CRC. Further studies are required to establish CRC surveillance in Japanese patients with UC.

Chitooligosaccharides promote radiosensitivity in colon cancer line SW480

AIM: To investigate the anti-proliferation and radiosensitization effect of chitooligosaccharides (COS) on human colon cancer cell line SW480.

METHODS: SW480 cells were treated with 0, 1.0, 2.0, 3.0, 4.0 and 5.0 mg/mL of COS for 48 h. CCK-8 assay was employed to obtain the cell survival ratio of SW480 cells, and the anti-proliferation curve was observed with the inhibition ratio of COS on SW480 cells. The RAY + COS group was treated with 1.0 mg/mL of COS for 48 h, while both the RAY and RAY+COS groups were exposed to X-ray at 0, 1, 2, 4, 6 and 8 Gy, respectively. Clonogenic assay was used to analyze cell viability in the two groups at 10 d after treatment, and a cell survival curve was used to analyze the sensitization ratio of COS. The RAY group was exposed to X-ray at 6 Gy, while the RAY+COS group was treated with 1.0 mg/mL of COS for 48 h in advance and exposed to X-ray at 6 Gy. Flow cytometry was employed to detect cell cycle and apoptosis rate in the non-treatment group, as well as in the RAY and RAY + COS groups after 24 h of treatment.

RESULTS: COS inhibited the proliferation of SW480 cells, and the inhibition rate positively correlated with the concentration of COS (P < 0.01). Cell viability decreased as radiation dose increased in the RAY and RAY+COS groups (P < 0.01). Cell viabilities in the RAY+COS group were lower than in the RAY group at all doses of X-ray exposure (P < 0.01), and the sensitization ratio of COS on SW480 cells was 1.39. Compared with the non-treatment group, there was a significant increase in apoptosis rate in both the RAY and RAY + COS groups; while the apoptosis rate in the RAY+COS group was significantly higher than in the RAY group (P < 0.01). In comparing these three groups, the percentage of G₂/M phase in both the RAY and RAY + COS groups significantly increased, and the percentage of the S phase and G₀/G₁ phase was downregulated. Furthermore, the percentage in the G₂/M phase was higher, and the percentage in the S phase and G₀/G₁ phase was lower in the RAY + COS group vs RAY group (P < 0.01).

CONCLUSION: COS can inhibit the proliferation of SW480 cells and enhance the radiosensitization of SW480 cells, inducing apoptosis and G₂/M phase arrest.

Chemoprevention trials of GI cancers in Asia

Cancers are among the leading causes of morbidity and mortality worldwide, with gastrointestinal (GI) luminal cancers accounting for a large proportion of cancer incidence. Chemoprevention of GI luminal cancers is important to reduce this cancer burden. Screening for and eradication of Helicobacter pylori (H. pylori) in areas with high gastric cancer incidence is a safe and effective strategy to decrease the incidence of gastric cancer. Eradication of H. pylori also seems to be effective in preventing metachronous cancer development after endoscopic resection of early gastric cancer. For the average risk individual, COX inhibitors may have a role in reducing the incidence of adenoma formation as well as colorectal cancer, bearing in mind its inherent risks. There is currently insufficient evidence to recommend a chemoprevention agent against esophageal and small intestine cancer.

Mesalamine, but Not Sulfasalazine, Reduces the Risk of Colorectal Neoplasia in Patients with Inflammatory Bowel Disease: An Agent-specific Systematic Review and Meta-analysis

BACKGROUND

In some studies, 5-aminosalicylates as a class have been associated with protective effects against colorectal cancer in inflammatory bowel disease. In practice, only mesalamine at doses greater than 1.2 g per day is currently widely in this setting. The specific impact of mesalamine at these doses has not has not previously been determined.

METHODS

We performed a systematic review and meta-analysis of the effect of mesalamine on risk of colorectal neoplasia (CRN) from prior cohort and case-control studies. Sensitivity analyses for study setting and case definition were performed. A quality assessment was made of all included studies.

RESULTS

Mesalamine was associated with a modest reduction in the odds ratio (OR) of CRN (OR = 0.6, 95% confidence interval, 0.4-0.9, P = 0.04). This effect was only noted in hospital-based studies and only in the reduction of all CRN (not cancers alone). Patients prescribed doses >1.2 g per day had a lower risk of CRN (OR = 0.5, 95% confidence interval, 0.3-0.9, P = 0.02) than lower doses. This effect was also only present in the hospital-based studies. In contrast, there was no reduction in the risk of CRN in patients prescribed sulfasalazine (OR = 0.8, 95% confidence interval, 0.5-1.2, P = 0.3), regardless of study setting.

CONCLUSIONS

Mesalamine, particularly at doses >1.2 g per day, produces a modest reduction in the risk of CRN in inflammatory bowel disease patient populations from referral centers. Sulfasalazine does not seem to reduce the risk. No benefit was noted in population-based studies.

The Demographic and Clinical Characteristics of Ulcerative Colitis in a Northeast Brazilian Population

INTRODUCTION

The purpose of this study was to describe the clinical and demographic characteristics of UC in Bahia, a Brazilian state, and to identify the variables associated with extensive colitis, steroid therapy, immunosuppression, and colectomy.

METHODS

In this cross-sectional study UC patients were interviewed, and additional information was collected from the medical records. Descriptive statistics and multivariate Poisson regression analysis were used.

RESULTS

This study included 267 individuals, the mean age of whom was 39.4 years at diagnosis. There was a predominance of females and left-side colitis. Extensive colitis was positively associated with male gender, diarrhea, weight loss, and a younger age at diagnosis. In contrast, active smoking and a family history of IBD were negatively associated with extensive colitis. Positive associations were observed between steroid therapy and diarrhea, weight loss, urban patients, extraintestinal manifestations (EIMs), and hospitalization. Younger age and weight loss at diagnosis, a family history of IBD, extensive colitis, EIMs, hospitalization, and steroid therapy were all positively associated with immunosuppression. In contrast, Caucasian individuals, smokers, patients with rectal bleeding, and rural patients areas were all observed to have a decreased likelihood of immunosuppression.

CONCLUSIONS

Our results corroborate the association between higher prevalence of extensive colitis and younger age at diagnosis. An association between steroid therapy and clinical presentation at diagnosis was observed. The observation that white individuals and rural patients use less immunosuppressive drugs highlights the need to study the influence of environmental and genetic factors on the behavior of UC in this population.

Dynamic changes and functions of macrophages and M1/M2 subpopulations during ulcerative colitis-associated carcinogenesis in an AOM/DSS mouse model

The high risk of developing colorectal carcinoma (CRC), from ulcerative colitis (UC), is well known. Macrophages are widely distributed immune cells that have an indispensable role in UC, as well as in CRC. However, little is currently known about the dynamic changes that occur in macrophage and M1/M2 macrophage subpopulations, during UC‑associated carcinogenesis. The aim of the present study was to investigate the alteration of colorectal macrophages and M1/M2 macrophage subpopulations during UC‑associated carcinogenesis. Both expression level alterations and functional changes were determined during UC‑associated carcinogenesis in an azoxymethane/dextran sodium sulfate‑induced chemically colitis‑associated carcinoma mouse model of Crj:CD‑1 (ICR) mice. Notable evidence from immunohistochemistry, flow cytometry, cytokine detection, and gene expression analyses demonstrated that M2 macrophages have a critical role in CRC initiation, promotion, and metastasis. M2 macrophages are associated with unbalanced pro‑inflammatory and anti‑inflammatory axes and aberrant enhancement of migration/invasion‑associated factors. Functional changes, similar to M2 polarized macrophages, were shown to occur in the M1 macrophages, without phenotypical changes, during the development of carcinoma and metastasis. The results of the present study suggest that M2 macrophages have a pro‑tumor role during UC‑associated carcinogenesis. Furthermore, similar functional changes occurred in the M1 macrophages, without polarization alterations, during carcinogenesis and metastasis.

Colorectal cancers in ulcerative colitis from a low-prevalence area for colon cancer

AIM: To determine the incidence and risk factors for colorectal cancer (CRC) in patients with ulcerative colitis from a low prevalence region for CRC.

METHODS: Our prospective database yielded a cohort of 430 patients [age: 44 ± 14.6 years; 248 men (57.7%)] with ulcerative colitis (median disease duration 6, range: 1-39 years) for analysis. Of these, 131 (30.5%) had left-sided colitis and 159 (37%) extensive colitis. Patients with histologically confirmed CRC within the segment with colitis were compared with those without CRC, to determine the risk factors for the development of CRC.

RESULTS: Twelve patients (2.8%) developed CRC. The overall incidence density was 3.56/1000 patient-years of disease - 3/1000 in the first 10 years, 3.3/1000 at 10 to 20 years, and 7/1000 at > 20 years. Three of our 12 patients developed CRC within 8 years of disease onset. On univariate analysis, extensive colitis, longer duration of disease, and poor control of disease were associated with development of CRC. On multivariate analysis, duration of disease and extent of colitis remained significant.

CONCLUSION: CRC occurred in 2.8% of patients with ulcerative colitis in our population - an incidence density similar to that in Western countries in spite of a low overall prevalence of colon cancer in our population. The risk increased with extent and duration of disease.

The risk of colorectal cancer in inflammatory bowel disease: a hospital-based cohort study from Korea

OBJECTIVE

Limited data are available on the incidence and risk factors of colorectal cancer (CRC) in Asian patients with inflammatory bowel disease (IBD).

MATERIAL AND METHODS

Information on 5212 Korean patients with IBD (2414 with Crohn's disease [CD] and 2798 with ulcerative colitis [UC]) was retrieved from the IBD registry of Asan Medical Center. Data on CRC incidence for the entire Korean population were derived from the Korean Statistical Information Service.

RESULTS

During 39,951 person-years of follow-up (17,679 for CD and 22,272 for UC), 30 patients (12 with CD and 18 with UC) developed CRC. The standardized incidence ratio (SIR) of CRC was 6.0 (95% confidence interval [CI], 3.10-10.48) for CD and 1.68 (95% CI, 1.00-2.66) for UC; it was 9.69 (95% CI, 5.01-16.93) for CD with colonic involvement and 4.31 (95% CI, 2.46-7.00) for extensive UC. The SIR was also increased in patients diagnosed with IBD at younger than 30 years old. CRC location was the low rectum in 11 of 12 CD patients (91.7%). The cumulative probability of rectal cancer was higher in CD patients with a perianal fistula than in those without a perianal fistula (p = 0.02).

CONCLUSIONS

A high prevalence of perianal fistulas in Korean CD patients may be the cause of the predominance of low rectal cancer in this population and the higher SIR of CRC in Koreans than in Westerners. In contrast, the SIR of CRC in Korean UC patients may be similar to that in Western UC patients.

Copy number variations are progressively associated with the pathogenesis of colorectal cancer in ulcerative colitis

AIM: To evaluate the association of known copy number variations (CNVs) in ulcerative colitis (UC) progressing to colorectal cancer.

METHODS: Microsatellite instability analysis using the National Cancer Institute’s panel of markers, and CNV association studies using Agilent 2 × 105 k arrays were done in tissue samples from four patient groups with UC: those at low risk (LR) or high risk of developing colorectal cancer, those with premalignant dysplastic lesions, and those with colitis-associated colorectal cancer (CAC). DNA from tissue samples of these groups were independently hybridized on arrays and analyzed. The data obtained were further subjected to downstream bioinformatics enrichment analysis to examine the correlation with CAC progression.

RESULTS: Microarray analysis highlighted a progressive increase in the total number of CNVs [LR (n = 178) vs CAC (n = 958), 5.3-fold], gains and losses [LR (n = 37 and 141) vs CAC (n = 495 and 463), 13.4- and 3.3-fold, respectively], size [LR (964.2 kb) vs CAC (10540 kb), 10.9-fold] and the number of genes in such regions [LR (n = 119) vs CAC (n = 455), 3.8-fold]. Chromosome-wise analysis of CNVs also showed an increase in the number of CNVs across each chromosome. There were 38 genes common to all four groups in the study; 13 of these were common to cancer genes from the Genetic Disease Association dataset. The gene set enrichment analysis and ontology analysis highlighted many cancer-associated genes. All the samples in the different groups were microsatellite stable.

CONCLUSION: Increasing numbers of CNVs are associated with the progression of UC to CAC, and warrant further detailed exploration.

Clinical characteristics and treatment of inflammatory bowel disease: A comparison of Eastern and Western perspectives

Inflammatory bowel disease (IBD) is a chronic, relapsing intestinal inflammatory disorder with unidentified causes. Both environmental factors and genetic aspects are believed to be crucial to the pathogenesis of IBD. The incidence and prevalence of IBD have recently been increasing throughout Asia, presumably secondary to environmental changes. This increasing trend in IBD epidemiology necessitates specific health care planning and education in Asia. To this end, we must gain a precise understanding of the distinctive clinical and therapeutic characteristics of Asian patients with IBD. The phenotypes of IBD reportedly differ considerably between Asians and Caucasians. Thus, use of the same management strategies for these different populations may not be appropriate. Moreover, investigation of the Asian-specific clinical aspects of IBD offers the possibility of identifying causative factors in the pathogenesis of IBD in this geographical area. Accordingly, this review summarizes current knowledge of the phenotypic manifestations and management practices of patients with IBD, with a special focus on a comparison of Eastern and Western perspectives.

Inflammatory Bowel Disease-related Colorectal Cancer in the Asia-Pacific Region: Past, Present, and Future

Patients with inflammatory bowel disease (IBD) are at an increased risk of developing colorectal cancer (CRC), and key contributing factors include chronic colonic inflammation and the extent and duration of disease. This increase in risk is more likely to result from chronic inflammation of the colonic mucosa than from any clearly defined genetic predisposition. However, globally, the true magnitude of this risk is debatable, since results from different studies are heterogeneous in terms of geographical and methodological variables. The prevalence of IBD-related CRC in the Asia-Pacific region ranges from 0.3% to 1.8% and a recent study found that the cumulative incidence of IBD-related CRC is comparable to that in Western countries. However, the CRC mortality rate in the Asia-Pacific region is on the rise compared with that in Western countries, and a few Asian countries show particularly rapid upward trends in CRC incidence. Although our understanding of the molecular and clinical basis for IBD-related CRC has improved substantially, our means of prevention, endoscopic surveillance, chemoprevention, and prophylactic surgery remain modest at best. Furthermore, published data on IBD-related CRC in the Asia-Pacific region is lacking, and this review addresses many aspects including epidemiology, natural history, etiopathogenesis, morphology, and biological behaviors of IBD-related CRC and sporadic CRC in the Asia-Pacific region. In this review, we will also discuss the risk factors for CRC in IBD patients, endoscopic technology screening, and surveillance programs and management strategies for IBD-related CRC.

Association of HLA-DRB1 alleles and anti-neutrophil cytoplasmic antibodies in Han and Uyghur patients with ulcerative colitis in China

OBJECTIVE

We aimed to study the association between HLA-DRB1 alleles and anti-neutrophil cytoplasmic antibodies (ANCA) among Uyghur and Han patients with ulcerative colitis (UC) in China.

METHODS

Altogether 160 UC patients and 466 healthy controls of Uyghur and Han groups residing in the Xinjiang Uyghur Autonomous Region of China were included. HLA-DRB1 variants were identified from genomic DNA using polymerase chain reaction and gene sequencing. Serum ANCA were determined by indirect immunofluorescence assay.

RESULTS

Among the Uyghur populations, the HLA-DRB1*08 gene frequency was lower in the UC patients than in the control group (P = 0.012, OR 0.12, 95% CI 0.02-0.91); however, that of HLA-DRB1*13 was much higher in the UC patients than in the controls (P = 0.001, OR 4.32, 95% CI 1.92-9.74). In Han patients with UC, there was no significant difference in HLA-DRB1 frequency between UC patients and healthy controls. The positive rate of ANCA in Uyghur patients with UC was significantly higher than in Han UC patients (P = 0.026), and ANCA positivity was associated with an increased frequency of HLA-DRB1*13 in Uyghur UC patients, but no such difference was observed in the Han patients.

CONCLUSIONS

Genetic polymorphisms of the HLA-DRB1*08 and *13 may contribute to the clinical heterogeneity of UC between Uyghur and Han UC patients in China. In Uyghur UC patients, HLA-DRB1*13 may be correlated with ANCA positivity.

5-Aminosalicylates reduce the risk of colorectal neoplasia in patients with ulcerative colitis: an updated meta-analysis

Background

Although the chemopreventive effect of 5-aminosalicylates on patients with ulcerative colitis has been extensively studied, the results remain controversial. This updated review included more recent studies and evaluated the effectiveness of 5-aminosalicylates use on colorectal neoplasia prevention in patients with ulcerative colitis.

Methods

Up to July 2013, we searched Medline, Embase, Web of Science, Cochrane CENTRAL, and SinoMed of China for all relevant observational studies (case-control and cohort) about the effect of 5-aminosalicylates on the risk of colorectal neoplasia among patients with ulcerative colitis. The Newcastle-Ottawa Scale was used to assess the quality of studies. Adjusted odds ratios (ORs) were extracted from each study. A random-effects model was used to generate pooled ORs and 95% confidence intervals (95%CI). Publication bias and heterogeneity were assessed.

Results

Seventeen studies containing 1,508 cases of colorectal neoplasia and a total of 20,193 subjects published from 1994 to 2012 were analyzed. 5-aminosalicylates use was associated with a reduced risk of colorectal neoplasia in patients with ulcerative colitis (OR 0.63; 95%CI 0.48–0.84). Pooled OR of a higher average daily dose of 5-aminosalicylates (sulfasalazine ≥ 2.0 g/d, mesalamine ≥ 1.2 g/d) was 0.51 [0.35–0.75]. Pooled OR of 5-aminosalicylates use in patients with extensive ulcerative colitis was 1.00 [0.53–1.89].

Conclusion

Our pooled results indicated that 5-aminosalicylates use was associated with a reduced risk of colorectal neoplasia in patients with ulcerative colitis, especially in the cases with a higher average daily dose of 5-aminosalicylates use. However, the chemopreventive benefit of 5-aminosalicylates use in patients with extensive ulcerative colitis was limited.

Systematic review with meta-analysis: the declining risk of colorectal cancer in ulcerative colitis

BACKGROUND

Patients with ulcerative colitis (UC) have an increased risk of developing colorectal cancer (CRC); however, the magnitude of this effect is open to debate.

AIM

To assess the risk of CRC in UC patients by systematic review and meta-analysis.

METHODS

A systematic literature search was performed up to November 2013. We selected studies describing the incidence and prevalence of CRC in patients with UC. Articles were assessed for quality using the Newcastle-Ottawa Scale. Cumulative incidence and incidence rates of CRC were combined and analysed using the generic inverse variance method. Sub-analyses were performed to identify factors associated with an increased risk of developing CRC.

RESULTS

A total of 81 studies (181 923 patients) met the inclusion criteria. The incidence rate of CRC in patients with UC was 1.58 per 1000 patient-years (py) [95% confidence interval (CI), 1.39–1.76]. Results were heterogeneous (I2 = 81–89%). The incidence rate was 4.02/1000 py (95%CI = 2.74–5.31) in studies that only included patients with extensive colitis, and 1.24/1000 py (95%CI = 1.01–1.47) in population-based studies. The incidence rate was 0.91/1000 py (95%CI = 0.61–1.2) in the first decade of disease, 4.07/1000 py (95%CI = 2.58–5.56) in the second, and 4.55/1000 py (95%CI = 2.64–6.46) in the third. The incidence rate decreased from 4.29/1000 py in the studies published in the 1950s to 1.21/1000 py in studies published in the last decade.

CONCLUSIONS

The risk of patients with ulcerative colitis developing colorectal cancer has decreased steadily over the last six decades, but the extent and duration of the disease increase this risk.

Colorectal cancer in inflammatory bowel disease: results of the 3rd ECCO pathogenesis scientific workshop (I)

Epidemiological studies demonstrate an increased risk of colorectal cancer in patients with inflammatory bowel disease (IBD). A detailed literature review was conducted on epidemiology, risk factors, pathophysiology, chemoprevention and outcomes of colorectal cancer (CRC) in IBD as part of the 3rd ECCO scientific pathogenesis workshop.

Difference in DRB1* gene polymorphisms between Han and Uyghur ulcerative colitis patients in China

AIM: To evaluate the association between HLA-DRB1 alleles and Han and Uyghur ulcerative colitis (UC) patients residing in the Xinjiang Uyghur Autonomous Region of China.

METHODS: In this study, 102 UC patients (53 Han including 22 men and 31 women, and 49 Uyghur patients including 25 men and 24 women; aged 48.07 ± 15.83 years) and 310 age- and sex-matched healthy controls were enrolled in the Department of Gastroenterology, Xinjiang People’s Hospital of China from January 2010 to May 2011. UC was diagnosed based on the clinical, endoscopic and histological findings following Lennard-Jones criteria. Blood samples were collected and genomic DNA was extracted by routine laboratory methods, and both polymerase chain reaction and gene sequencing were used to identify HLA-DRB1 allele variants. The potential association between genetic variation and UC in Han and Uyghur patients was examined. There were no statistical differences in HLA-DRB1 allele frequencies in Han UC patients.

RESULTS: There was no significant difference in the sex ratio between the controls and UC patients (P = 0.740). In Han patients with UC (n = 53), HLA-DRB1 *03, *13 allele frequencies were lower than in healthy controls (n = 161), but not statistically significant, and HLA-DRB1*04*11*14 allele frequencies were higher than in healthy controls, but without statistical significance. Differences between Uyghur UC patients and the control group were observed for HLA-DRB1*04 and HLA-DRB1*13, both showed a greater frequency in UC patients (10.21% vs 2.69%, P = 0.043; 14.29% vs 4.03%, P = 0.019). HLA-DRB1*14 also showed a greater frequency in UC patients (14.29% vs 2.69%, P = 0.006). The frequencies of DRB1*04, *13*14 alleles were increased in Uyghur UC patients compared with normal controls. The frequency of DRB1 * 08 was decreased in Uyghur UC patients compared with normal controls. HLA-DRB1 alleles showed no association with UC in Han patients. There were no statistical differences in HLA-DRB1 allele frequencies in Han UC patients. The frequencies of DRB1*04, *13*14 alleles were increased in Uyghur UC patients compared with normal controls. The frequency of DRB1*08 was decreased in Uyghur UC patients compared with normal controls. Polymorphism of the HLA-DRB1 gene may contribute to the clinical heterogeneity of UC between Han and Uyghur UC patients in China.

CONCLUSION: HLA-DRB1*04*13*14 and DRB1*08 may contribute to the clinical heterogeneity of UC between Han and Uyghur UC patients.

Inflammatory bowel disease in Asia: a systematic review

The incidence and prevalence of inflammatory bowel diseases (IBD), Crohn's disease (CD) and ulcerative colitis (UC), are lower in Asia than in the West. However, across Asia the incidence and prevalence of IBD has increased rapidly over the last two to four decades. These changes may relate to increased contact with the West, westernization of diet, increasing antibiotics use, improved hygiene, vaccinations, or changes in the gut microbiota. Genetic factors also differ between Asians and the Caucasians. In Asia, UC is more prevalent than CD, although CD incidence is rapidly increasing in certain areas. There is a male predominance of CD in Asia, but a trend towards equal sex distribution for UC. IBD is diagnosed at a slightly older age than in the West, and there is rarely a second incidence peak as in the West. A positive family history is much less common than in the West, as are extra-intestinal disease manifestations. There are clear ethnic differences in incidence within countries in Asia, and an increased incidence in IBD in migrants from Asia to the West. Research in Asia, an area of rapidly changing IBD epidemiology, may lead to the discovery of critical etiologic factors that lead to the development of IBD.