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

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.

Perianal Crohn's disease and the development of colorectal and anal cancer: A systematic review and meta-analysis

BACKGROUND AND AIMS

The aim of this systematic review was to assess the literature on the incidence and risk factors for colorectal cancer and anal cancer in patients with perianal Crohn's disease.

METHOD

A systematic review of the literature was performed using PubMed, Embase and Google Scholar. A meta-analysis was then conducted using a random-effect model.

RESULTS

Five studies were included in the systematic review. Out of all patients, 26.5% had perianal Crohn's Disease. The median follow-up was six years. In total, 127 cases of colorectal cancer were found (0.43% of the included Crohn's disease patients). Perianal involvement was present in 50% of colorectal cancer patients (0.89% of the population). Three of the studies specified the cancer to be rectal or anal, which were present in 68 and 24 cases (0.3% and 0.1% of patients), respectively. In a subgroup analysis of rectal- and anal cancer, perianal involvement was most frequent in anal cancer, accounting for 46% of the cases. In the rectal cancer group, 37% had perianal involvement. The higher incidence of colorectal cancer in patients with perianal Crohn's was confirmed in a meta-analysis.

CONCLUSION

Half of patients with colorectal cancer and anal cancer were found to have perianal Crohn's. In patients with perianal involvement, there was a higher percentage of anal cancer compared with rectal cancer. These results support the theory that patients with perianal Crohn's are at increased risk for developing colorectal- and anal cancer. Studies, collecting more detailed data about patients and their cancers, are necessary to further specify the disease course.

Incident Crohn's Disease as a Risk Factor for Colorectal Cancer in the First 10 Years after Diagnosis: A Nationwide Population-Based Study

We investigated the risk of colorectal cancer (CRC) in patients with Crohn's disease (CD) using the claims data of the Korean National Health Insurance during 2006-2015. The data of 13,739 and 40,495 individuals with and without CD, respectively, were analyzed. Hazard ratios (HRs) were calculated using multivariate Cox proportional hazard regression tests. CRC developed in 25 patients (0.18%) and 42 patients (0.1%) of the CD and non-CD groups, respectively. The HR of CRC in the CD group was 2.07 (95% confidence interval (CI), 1.25-3.41). The HRs of CRC among men and women were 2.02 (95% CI 1.06-3.87) and 2.10 (95% CI, 0.96-4.62), respectively. The HRs of CRC in the age groups 0-19, 20-39, 40-59, and ≥60 years were 0.07, 4.86, 2.32, and 0.66, respectively. The HR of patients with late-onset CD (≥40 years) was significantly higher than that of those with early-onset CD (<40 years). CD patients were highly likely to develop CRC. Early-onset CD patients were significantly associated with an increased risk of CRC than matched individuals without CD. However, among CD patients, late-onset CD was significantly associated with an increased risk of CRC.

Current status of inflammatory bowel diseases in Korea

Background: Inflammatory bowel disease (IBD) is a disease of unknown origin that causes chronic inflammation of the intestines and is classified as either ulcerative colitis or Crohn’s disease. The incidence and prevalence of IBD in Korea have been rapidly increasing during the past three decades. This paper describes the current status of IBD in Korea.Current Concepts: Compared with western countries, genotypes and phenotypes of IBD in Korea demonstrate some distinct features, which may have an impact on the diagnosis, treatment, and prognosis of IBD. We continue to experience some difficulties in making early and accurate diagnoses of IBD in Korea due to a low awareness of the disease and the high prevalence of infectious enterocolitis, such as intestinal tuberculosis, which needs to be differentiated from IBD. The treatment of IBD can be influenced by differences in genetic, environmental, and social factors. NUDT15 variants limit the use of thiopurines. Infectious diseases, including tuberculosis, hepatitis B, and cytomegalovirus colitis, are usually more common in Asia than in western countries and can adversely influence the management of IBD. Biologic agents, which have changed the treatment paradigm of IBD, are equally efficacious in Asian patients as in Western patients. However, their use is limited due to a strict Korean government health insurance reimbursement policy. The prognosis of ulcerative colitis in Korea may be better than that in western countries, as indicated by a lower colectomy rate. However, this difference is less distinct in Crohn’s disease.Discussion and Conclusion: IBD in Korea differs from that in western countries in many respects. With rapid increase in the prevalence of IBD in Korea, medical costs for IBD are expected to become a significant financial burden. Koreans need to be prepared for this eventuality.

Clinical Characteristics and Long-term Outcomes of Pediatric Ulcerative Colitis: A Single-Center Experience in Korea

Background/Aims

Although pediatric ulcerative colitis (UC) has a different phenotype and clinical course than adult UC, its clinical features and outcomes are poorly defined, especially in Asian populations. This study investigated the clinical features and long-term outcomes of pediatric UC in a Korean population.

Methods

We retrospectively analyzed 208 patients aged <18 years diagnosed with UC between 1987 and 2013. The patient characteristics at diagnosis according to the Paris classification and the clinical course were analyzed.

Results

The male-to-female ratio was 1.3:1, and the median patient age was 15.5 years. At diagnosis, 28.8% of patients had proctitis (E1), 27.8%, left-sided colitis (E2); 5.2%, extensive colitis (E3); and 38.2%, pancolitis (E4). The cumulative probabilities of extension after 5, 10, 15, and 20 years were 32.7%, 40.4%, 52.5%, and 65.8%, respectively. Eighteen patients underwent colectomy, and three patients had colorectal cancer. The cumulative probabilities of colectomy after 5, 10, 15, and 20 years were 7.1%, 8.9%, 12.6%, and 15.6%, and those of colorectal cancer after 10, 15, and 20 years were 0%, 2.1%, and 12.0%, respectively. The disease extent, Pediatric Ulcerative Colitis Activity Index severity, and systemic corticosteroid therapy were significant risk factors for colectomy. The development of primary sclerosing cholangitis was significantly associated with colorectal cancer.

Conclusions

This study provides detailed information on the disease phenotype and long-term clinical outcomes in a large cohort of Korean children with UC. They have extensive disease at diagnosis, a high rate of disease extension, and a low rate of cumulative colectomy.

Prognostic Factors for Advanced Colorectal Neoplasia in Inflammatory Bowel Disease: Systematic Review and Meta-analysis

BACKGROUND AND AIMS

Patients with inflammatory bowel disease (IBD) have an increased risk of colorectal cancer (CRC). We performed a systematic review and meta-analysis to identify all prognostic factors for advanced colorectal neoplasia (aCRN, high-grade dysplasia, or CRC) in patients with IBD.

METHODS

A systematic literature search was conducted according to the Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines. Risk of bias was assessed using the Quality in Prognostic Studies tool. Random-effects models were created separately for odds and hazard ratios, different study designs, and univariable or multivariable data. The evidence for all prognostic factors was categorized as "weak", "moderate", or "strong", based on estimate of effect sizes, heterogeneity, and risk of bias.

RESULTS

A total of 164 studies were included, allowing pooled analysis of 31 potential prognostic factors. In the univariable analysis, the evidence for extensive disease was classified as strong while evidence for low-grade dysplasia, strictures, primary sclerosing cholangitis, post-inflammatory polyps, family history of CRC, and ulcerative colitis versus Crohn's disease was considered moderate. Evidence for any dysplasia, colon segment resection, aneuploidy, male sex, and age was classified as weak. In addition, histologic inflammation was identified as a risk factor in multivariable analysis (weak evidence). The evidence for the protective factors colonoscopic surveillance, 5-Aminosalicylic Acid, thiopurines, and smoking was moderate in univariable analysis. Multivariable analysis provided weak evidence for statin use.

CONCLUSIONS

In this systematic review and meta-analysis, we identified 13 risk factors and 5 protective factors for aCRN in IBD patients, based on univariable and/or multivariable pooled analyses. These findings might lay the groundwork for an improved CRC risk stratification-based surveillance in IBD.

Clinical features and treatment of inflammatory bowel disease in a low-incidence area: A hospital-based retrospective cohort study in Taiwan

Inflammatory bowel disease (IBD) has emerged in the Asia-Pacific area over the past 2 decades. There is a paucity of clinical data regarding real-world experience of patients with IBD from low endemic area such as Taiwan. Therefore, the present study aimed to review the clinical features of patients with IBD form a tertiary center from Taiwan.A total of 163 patients with IBD were identified from the electronic clinical database of Changhua Christian Hospital. Demographic data of the patients and clinical features of the disease pattern were retrospectively reviewed.There was a higher proportion (62.6%) of patients diagnosed with ulcerative colitis (UC). Patients with Crohn disease (CD) and UC had male predominance. The median age of diagnosis was younger in patients with CD than in patients with UC (CD vs UC: 31 vs 40 years, P = .0423). The disease distribution of UC was as follows: E1 (15.7%), E2 (47.1%), and E3 (37.3%). The disease distribution of CD was as follows: L1 (36.1%), L2 (14.8%), L3 (42.6%), and L4 (6.5%). The majority of patients with CD had a complicated presentation with B2 (32.8%) and B3 (32.8%). Patients with CD had a higher bowel resection rate than patients with UC. Patients with CD were more likely to be treated with immunomodulator and biologics and those with UC were more likely to be treated with 5-aminosalicylic acid (5-ASA). A trend of decreased bowel resection for patients with IBD and less severe phenotype of patients with CD were observed after 2015.UC with male predominance was the predominant type of IBD in the study. Patients with CD are likely to have a complicated disease course, requiring a higher demand of biologic therapy than patients with UC.

Medical and Endoscopic Management of Crohn Disease

ABSTRACT

In this review, through a series of questions and answers, we explore the current approach to classifying patients with Crohn disease into low-risk (mild-moderate) and high-risk (moderate-severe) categories with the recommended treatment approaches per guidelines from the International Organization for the Study of Inflammatory Bowel Diseases, American Gastroenterological Association, the American College of Gastroenterology, and the European Crohn's and Colitis Organization detailed here. The development pipeline of potential therapies is also summarized. We also review key information from magnetic resonance enterography and pelvis imaging studies that the abdominal radiologist can communicate to a multidisciplinary treatment team that includes gastroenterologists and colorectal surgeons, with a goal of achieving optimal patient outcomes. Lastly, endoscopic and radiological treatment targets in a treat-to-target approach in Crohn disease are explored.

Intestinal cancer in patients with Crohn's disease: A systematic review and meta-analysis

BACKGROUND AND AIM

Although surveillance colonoscopy is recommended by several guidelines for Crohn's disease (CD), the evidence is insufficient to support the validity of this recommendation. Moreover, the efficacy of surveillance colonoscopy for anorectal cancer remains unclear. Therefore, we performed a systematic review of cancer in patients with CD before considering the proper surveillance methods.

METHODS

We conducted a systematic review and meta-analysis examining the incidence of intestinal cancer and a literature review to clarify the characteristic features of cancer in CD. We performed the systematic literature review of studies published up to May 2019.

RESULTS

Overall, 7344 patients were included in eight studies. The standardized incidence ratios (95% confidence intervals) of colorectal cancer (CRC) and small bowel cancer (SBC) were 2.08 (1.43-3.02) and 22.01 (9.10-53.25), respectively. The prevalence of CRC and SBC was 57/7344 (0.77%) and 17/7344 (0.23%), respectively, during a median follow-up of 12.55 years. Additionally, 54 studies reporting 208 anorectal cancer cases were identified. In patients with anorectal cancer, the prognosis for survival was 2.1 ± 2.3 years, and advanced cancer greater than stage T3 occurred in 46/74 patients (62.1%). Many more reports of anorectal cancer were published in Asia than in Western countries.

CONCLUSION

Although we were unable to state a recommendation for surveillance for SBC, we should perform cancer surveillance for CRC in patients with CD. However, the characteristics of cancer may differ according to geography or race. We must establish proper and effective surveillance methods that are independently suitable to detect these differences.

Inflammatory bowel disease and risk of gastric, small bowel and colorectal cancer: a meta-analysis of 26 observational studies

PURPOSE

The purpose of this meta-analysis was to assess the associations between inflammatory bowel disease (IBD) and risk of the gastric, small bowel and colorectal cancer.

METHODS

We searched the PubMed and Web of Science for observational studies published before June 2020, and the quality of each included study was evaluated according to the Newcastle-Ottawa-Scale.

RESULTS

Twenty-six studies comprising 531 449 IBD patients and more than 65 million reference individuals were included. Although IBD was significantly associated with 67% increased risk of the total gastric, small bowel and colorectal cancer. After stratifying by cancer location, IBD mainly increased the risk of intestinal cancer instead of gastric cancer. Furthermore, Crohn's disease (CD) significantly increased the risk of both small bowel cancer and colorectal cancer, while ulcerative colitis (UC) only increased the risk of colorectal cancer. In subgroup analysis, associations between IBD and risk of total gastric, small bowel and colorectal cancer were similar between male and female, except for that male IBD patients but not female had a significantly higher risk of small bowel cancer. Additionally, IBD patients in different geographical areas had different associations with risk of various gastrointestinal tract cancers.

CONCLUSIONS

IBD is mainly associated with increased risk of cancers in the lower gastrointestinal tract, including small bowel cancer and colorectal cancer. Because studies about the association between IBD and risk of gastric cancer and the populations in Asia are limited, more observational studies are required in the future.

Single Nucleotide Polymorphisms in Colitis-Associated Colorectal Cancer: A Current Overview with Emphasis on the Role of the Associated Genes Products

Colitis-Associated Colorectal Cancer (CA-CRC) is one of the most severe complications of Inflammatory Bowel Disease (IBD) and constitutes the cause of death in 10-15% of patients. The risk ratio for carcinogenesis depends on numerous factors, such as the extent of intestinal inflammatory lesions and the duration of the disease. CA-CRC is a major problem of today's gastroenterology and colorectal surgery due to the fact that the incidence and prevalence of IBD are increasing. In this review, we discussed the current state of knowledge regarding genetic differences between sporadic CRC and CA-CRC, especially pertaining to the chromosomal instability mechanism (CIN). In order to explain CA-CRC molecular basis, we have analyzed the data from studies regarding the correlations between CA-CRC and the presence of Single Nucleotide Polymorphisms (SNPs). Further focus on the role of associated proteins has emphasized the role of NF-κB signaling as the main link between inflammation and carcinogenesis during the course of IBD.

Incidence and Outcomes of Perianal Disease in an Asian Population with Crohn's Disease: A Nationwide Population-Based Study

BACKGROUND

Little is known about the natural history of perianal fistulas in Asian populations with Crohn's disease (CD).

AIMS

We investigated the incidence and outcomes of perianal CD (pCD) in Korean CD patients.

METHODS

A nationwide population-based cohort of 6265 CD patients diagnosed in 2010-2014 was analyzed to investigate the incidence and outcomes of pCD. The results were validated in a hospital-based cohort of 2923 CD patients diagnosed in 1981-2015. Factors associated with pCD development were analyzed. The incidence and outcomes of pCD were compared between the prebiologic and biologic eras.

RESULTS

pCD occurred in 39.2% of the population-based cohort and 56.1% of the hospital-based cohort during the median follow-up of 4.2 and 8.5 years, respectively. The cumulative incidence of pCD was 40.0% at 5 years after CD diagnosis in the population-based cohort and 62.5% at 20 years in the hospital-based cohort. In multivariate analysis, pCD development was positively associated with male sex, younger age and colonic involvement at diagnosis, early diagnosis, and CD diagnosis in the prebiologic era. The cumulative probability of proctectomy at 10, 20, and 30 years after pCD diagnosis was 2.9%, 12.2%, and 16.2%, respectively. The cumulative incidence of pCD occurring after CD diagnosis and the cumulative probability of proctectomy were significantly lower in the biologic era than in the prebiologic era (p < 0.001 and p = 0.03, respectively).

CONCLUSIONS

Compared with Western patients with CD, Korean patients show a high incidence of pCD but have a low probability of proctectomy, suggesting the favorable course of pCD.

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.

Update on the Natural Course of Fistulizing Perianal Crohn's Disease in a Population-Based Cohort

BACKGROUND

This study sought to re-estimate the cumulative incidence of perianal or rectovaginal fistulas and the associated proctectomy rate in the prebiologic era vs the biologic era using a population-based cohort of Crohn's disease (CD) patients.

METHODS

The medical records of 414 residents of Olmsted County, Minnesota, who were diagnosed with CD between 1970 and 2010 were reviewed. The cumulative incidence of perianal or rectovaginal fistulas from time of CD diagnosis and the cumulative rate of proctectomy from date of first perianal or rectovaginal fistula diagnosis were estimated using the Kaplan-Meier method.

RESULTS

Eighty-five patients (20.5%) diagnosed with CD between 1970 and 2010 had at least 1 perianal or rectovaginal fistula episode between January 1, 1970, and June 30, 2016. The cumulative incidence of perianal or rectovaginal fistulas was 18% after 10 years, 23% after 20 years, and 24% after 30-40 years from CD diagnosis. The cumulative incidence of perianal or rectovaginal fistulas was significantly lower in patients diagnosed in 1998 or after than in patients diagnosed before 1998 (P = 0.03, log-rank). Among 85 patients developing perianal or rectovaginal fistulas, 16 patients (18.8%) underwent proctectomy for the treatment of perianal or rectovaginal fistulas during follow-up.

CONCLUSIONS

In a population-based inception cohort of CD, one-fifth of patients were diagnosed with at least 1 perianal or rectovaginal fistula. The cumulative probability of perianal or rectovaginal fistulizing disease has decreased over time.

Immunoprofiling of Colitis-associated and Sporadic Colorectal Cancer and its Clinical Significance

Immunoprofiling is useful for predicting prognosis in various malignancies and provides targets for immunotherapy. Quantitative multispectral imaging system, which allows simultaneous detection of multiple immune markers, is a novel method for examining the tumor immune environment. We compared the expression levels of various surface markers in immune cells between colitis-associated cancer (CAC) and sporadic colorectal cancer (CRC) and evaluated the clinical usefulness of immunoprofiling in CRC. Tumor specimens from 24 CAC patients and 48 sporadic CRC patients, matched by age, sex, and tumor location to CAC, were included in the analysis. The expression levels of CD3, CD8, Foxp3, and programmed death-ligand 1 (PD-L1) in immune cells at the invasive margins of tumor tissues were evaluated by quantitative multispectral imaging. The CAC group had significantly less levels of cells expressing CD3, CD8, Foxp3, or PD-L1 (all, p < 0.01). In the CAC group, patients whose immune cells had high expression of CD3⁺ and CD8⁺ had better overall survival. The immune profiling patterns of CAC patients were significantly distinct from those of sporadic CRC patients, suggesting that CAC and sporadic CRC have distinct disease phenotypes. Immunoprofiling can be helpful for evaluation of clinical prognosis in CAC.

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.

Crohn's disease diagnosis, treatment approach, and management paradigm: what the radiologist needs to know

Crohn's disease is one of the major subtypes of idiopathic inflammatory bowel disease and is characterized by chronic transmural intestinal inflammation of the gastrointestinal tract anywhere from mouth to the anus, with a predilection for the small bowel. Cross-sectional imaging with computed tomography and magnetic resonance enterography plays a key role in confirming diagnosis, identifying and managing complications, assessing disease severity, and identifying response to medical therapy. This review will focus on the role of radiologists in the diagnosis and assessment of Crohn's disease. Additionally, a review of current medical therapy approaches, available medications, and side effects will be discussed. The review will also highlight key complications of medical therapy and associated diseases that should be evaluated by the radiologist with cross-sectional imaging.

Overall and cause-specific mortality in Korean patients with inflammatory bowel disease: A hospital-based cohort study

BACKGROUND AND AIM

Limited data are available regarding mortality from inflammatory bowel disease in non-Caucasian populations. Herein, we evaluated overall and cause-specific mortality in a hospital-based cohort of Korean inflammatory bowel disease patients.

METHODS

We determined mortality in 2414 Crohn's disease patients and 2798 ulcerative colitis patients diagnosed between 1977 and 2013. Standardized mortality ratios were calculated in several demographic and phenotypic subgroups.

RESULTS

During the mean 9-year follow up, 114 patients died: 35 with Crohn's disease and 79 with ulcerative colitis. The overall standardized mortality ratios were 1.40 (95% confidence interval: 0.97-1.94) in Crohn's disease and 0.73 (0.58-0.91) in ulcerative colitis. In Crohn's disease, female sex, age < 30 years at diagnosis, disease duration > 10 years, ileocolonic disease at diagnosis, perianal fistula, intestinal resection, and ever-use of corticosteroids were associated with higher mortality. In ulcerative colitis, male sex, age ≥ 30 years at diagnosis, disease duration ≤ 5 years, proctitis at diagnosis, and no history of colectomy were associated with lower mortality, while primary sclerosing cholangitis was associated with higher mortality. In both Crohn's disease and ulcerative colitis, high mortality rates due to nonmalignant gastrointestinal causes (standardized mortality ratios: 4.59 and 2.32, respectively) and gastrointestinal malignancies (standardized mortality ratios: 16.59 and 3.45, respectively) were observed. Cardiovascular mortality was lower in ulcerative colitis (standardized mortality ratio: 0.47).

CONCLUSIONS

The overall mortality tended to be higher in Crohn's disease patients than in the general population; it was slightly lower in ulcerative colitis patients than in the general population.

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.

[Recent Advances in Understanding Colorectal Cancer and Dysplasia Related to Ulcerative Colitis]

Ulcerative colitis is an idiopathic chronic inflammatory bowel disease and its incidence in Korea has rapidly increased over the past two decades. Since ulcerative colitis is associated with increased risk for colorectal cancer, annual or biannual colonoscopy with four quadrant random biopsies at every 10 cm segments has been recommended for surveillance of colitic cancer in patients with long standing left-sided or extensive colitis. Recent epidemiologic data and meta-analysis suggest that the increment of colorectal cancer risk in ulcerative colitis was not larger than that of previous studies. Moreover, in addition to the extent and duration of colitis, other risk factors such as family history of colorectal cancer, primary sclerosing cholangitis, stricture, pseudopolyps, and histologic severity of inflammation have been recognized. As a result, updated guidelines provide surveillance strategies adjusted to the individual patient's risk for colitic cancer. Regarding surveillance method, target biopsy under panchromoendoscopy is preferentially recommended rather than random biopsy.

Nutritional Modulation of Gene Expression: Might This be of Benefit to Individuals with Crohn's Disease?

The incidence of inflammatory bowel diseases (IBD), including Crohn's disease (CD), is increasing worldwide, especially in young children and adolescents. Although hospitalized patients are usually provided with enteral or parenteral support, continuing care typically requires a trial-and-error approach to suppressing symptoms and maintaining disease remission. Current nutritional advice does not differ from general population guidelines. International collaborative studies have revealed 163 distinct genetic loci affecting susceptibility to IBD, in some of which host-microbe interactions can be seen to play an important role. The nature of these loci enables a rationale for predicting nutritional requirements that may not be evident through standard therapeutic approaches. Certain recognized nutrients, such as vitamin D and long-chain omega-3 polyunsaturated fatty acids, may be required at higher than anticipated levels. Various phytochemicals, not usually considered in the same class as classic nutrients, could play an important role. Prebiotics and probiotics may also be beneficial. Genomic approaches enable proof of principle of nutrient optimization rather than waiting for disease symptoms to appear and/or progress. We suggest a paradigm shift in diagnostic tools and nutritional therapy for CD, involving a systems biology approach for implementation.

Inflammatory Bowel Disease Cohort Studies in Korea: Present and Future

Inflammatory bowel disease (IBD) is defined as a chronic and relapsing inflammatory disorder of the intestine. Intestinal inflammation in IBD has been proposed to be attributable to the interplay between microbial, genetic, environmental, and immunological factors. The incidence and prevalence rates of IBD are rapidly increasing apparently in other parts of the world, with dramatic increases especially in East Asia. Generally, cohort studies are useful for estimating the incidence, prevalence, natural course, prognosis, and risk factors of diseases. In particular, cohort studies performed in Western countries have well described the prevalence, risk factors, and natural course of IBD and investigated its genetic pathophysiology. However, the outcomes of IBD cohort studies performed in Korea are not as persuasive as those of Western studies because of the relatively low prevalence of IBD and short follow-up periods of the cohorts in Korea. Despite this critical limitation, members of the Korean Association for the Study of Intestinal Diseases have demonstrated outstanding results. Some unique features of IBD patients in Korea are well demonstrated, such as thiopurine-induced leukopenia or risks of opportunistic tuberculosis infection in patients receiving tumor necrosis factor-α inhibitors. In this review, the present authors summarized the key points of the results of the cohort studies performed in Korea and explored future perspectives.

Non-polypoid colorectal neoplasms: Classification, therapy and follow-up

In the last years, an increasing interest has been raised on non-polypoid colorectal tumors (NPT) and in particular on large flat neoplastic lesions beyond 10 mm tending to grow laterally, called laterally spreading tumors (LST). LSTs and large sessile polyps have a greater frequency of high-grade dysplasia and local invasiveness as compared to pedunculated lesions of the same size and usually represent a technical challenge for the endoscopist in terms of either diagnosis and resection. According to the Paris classification, NPTs are distinguished in slightly elevated (0-IIa, less than 2.5 mm), flat (0-IIb) or slightly depressed (0-IIc). NPTs are usually flat or slightly elevated and tend to spread laterally while in case of depressed lesions, cell proliferation growth progresses in depth in the colonic wall, thus leading to an increased risk of submucosal invasion (SMI) even for smaller neoplasms. NPTs may be frequently missed by inexperienced endoscopists, thus a careful training and precise assessment of all suspected mucosal areas should be performed. Chromoendoscopy or, if possible, narrow-band imaging technique should be considered for the estimation of SMI risk of NPTs, and the characterization of pit pattern and vascular pattern may be useful to predict the risk of SMI and, therefore, to guide the therapeutic decision. Lesions suitable to endoscopic resection are those confined to the mucosa (or superficial layer of submucosa in selected cases) whereas deeper invasion makes endoscopic therapy infeasible. Endoscopic mucosal resection (EMR, piecemeal for LSTs > 20 mm, en bloc for smaller neoplasms) remains the first-line therapy for NPTs, whereas endoscopic submucosal dissection in high-volume centers or surgery should be considered for large LSTs for which en bloc resection is mandatory and cannot be achieved by means of EMR. After piecemeal EMR, follow-up colonoscopy should be performed at 3 mo to assess resection completeness. In case of en bloc resection, surveillance colonoscopy should be scheduled at 3 years for adenomatous lesions ≥ 1 cm, or in presence of villous features or high-grade dysplasia patients (regardless of the size), while less intensive surveillance (colonoscopy at 5-10 years) is needed in case of single (or two) NPT < 1 cm presenting tubular features or low-grade dysplasia at histology.