A meta-analysis of the clinicopathological characteristics and survival outcomes of inflammatory bowel disease associated colorectal cancer

Obesity and early-onset colorectal cancer risk: emerging clinical evidence and biological mechanisms

Early-onset colorectal cancer (EOCRC) is defined as diagnosed at younger than 50 years of age and indicates a health burden globally. Patients with EOCRC have distinct risk factors, clinical characteristics, and molecular pathogenesis compared with older patients with CRC. Further investigations have identified different roles of obesity between EOCRC and late-onset colorectal cancer (LOCRC). Most studies have focused on the clinical characteristics of obesity in EOCRC, therefore, the mechanism involved in the association between obesity and EOCRC remains inconclusive. This review further states that obesity affects the carcinogenesis of EOCRC as well as its development and progression, which may lead to obesity-related metabolic syndrome, intestinal dysbacteriosis, and intestinal inflammation.

LRRK2 G2019S Promotes Colon Cancer Potentially via LRRK2-GSDMD Axis-Mediated Gut Inflammation

Leucine-rich repeat kinase 2 (LRRK2) is a serine-threonine protein kinase belonging to the ROCO protein family. Within the kinase domain of LRRK2, a point mutation known as LRRK2 G2019S has emerged as the most prevalent variant associated with Parkinson's disease. Recent clinical studies have indicated that G2019S carriers have an elevated risk of cancers, including colon cancer. Despite this observation, the underlying mechanisms linking LRRK2 G2019S to colon cancer remain elusive. In this study, employing a colitis-associated cancer (CAC) model and LRRK2 G2019S knock-in (KI) mouse model, we demonstrate that LRRK2 G2019S promotes the pathogenesis of colon cancer, characterized by increased tumor number and size in KI mice. Furthermore, LRRK2 G2019S enhances intestinal epithelial cell proliferation and inflammation within the tumor microenvironment. Mechanistically, KI mice exhibit heightened susceptibility to DSS-induced colitis, with inhibition of LRRK2 kinase activity ameliorating colitis severity and CAC progression. Our investigation also reveals that LRRK2 G2019S promotes inflammasome activation and exacerbates gut epithelium necrosis in the colitis model. Notably, GSDMD inhibitors attenuate colitis in LRRK2 G2019S KI mice. Taken together, our findings offer experimental evidence indicating that the gain-of-kinase activity in LRRK2 promotes colorectal tumorigenesis, suggesting LRRK2 as a potential therapeutic target in colon cancer patients exhibiting hyper LRRK2 kinase activity.

Overcoming cancer risk in inflammatory bowel disease: new insights into preventive strategies and pathogenesis mechanisms including interactions of immune cells, cancer signaling pathways, and gut microbiota

Inflammatory bowel disease (IBD), characterized primarily by gastrointestinal inflammation, predominantly manifests as Crohn's disease (CD) and ulcerative colitis (UC). It is acknowledged that Inflammation plays a significant role in cancer development and patients with IBD have an increased risk of various cancers. The progression from inflammation to carcinogenesis in IBD is a result of the interplay between immune cells, gut microbiota, and carcinogenic signaling pathways in epithelial cells. Long-term chronic inflammation can lead to the accumulation of mutations in epithelial cells and the abnormal activation of carcinogenic signaling pathways. Furthermore, Immune cells play a pivotal role in both the acute and chronic phases of IBD, contributing to the transformation from inflammation to tumorigenesis. And patients with IBD frequently exhibit dysbiosis of the intestinal microbiome. Disruption of the gut microbiota and subsequent immune dysregulation are central to the pathogenesis of both IBD and colitis associated colorectal cancer (CAC). The proactive management of inflammation combined with regular endoscopic and tumor screenings represents the most direct and effective strategy to prevent the IBD-associated cancer.

Impact of previous diverticulitis on 5-year survival and recurrence rates in patients with colorectal cancer

BACKGROUND

Diverticulitis and colorectal cancer (CRC) share epidemiological characteristics, but their relationship remains unknown. It is unclear if prognosis following CRC differ for patients with previous diverticulitis compared to those with sporadic cases and patients with inflammatory bowel disease or hereditary syndromes.

AIM

The aim was to determine 5-year survival and recurrence after colorectal cancer in patients with previous diverticulitis, inflammatory bowel disease and hereditary colorectal cancer compared to sporadic cases.

METHODS

Patients <75 years of age diagnosed with colorectal cancer at Skåne University Hospital Malmö, Sweden, between January 1st 2012 and December 31st 2017 were identified through the Swedish colorectal cancer registry. Data was retrieved from the Swedish colorectal cancer registry and chart review. Five-year survival and recurrence in colorectal cancer patients with previous diverticulitis were compared to sporadic cases, inflammatory bowel disease associated and hereditary colorectal cancer.

RESULTS

The study cohort comprised 1052 patients, 28 (2.7%) with previous diverticulitis, 26 (2.5%) IBD, 4 (1.3%) hereditary syndromes and 984 (93.5%) sporadic cases. Patients with a history of acute complicated diverticulitis had a significantly lower 5-year survival rate (61.1%) and higher recurrence rate (38.9%) compared to sporadic cases (87.5% and 18.8% respectively).

CONCLUSION

Patients with acute complicated diverticulitis had worse 5-year prognosis compared to sporadic cases. The results emphasize the importance of early detection of colorectal cancer in patients with acute complicated diverticulitis.

Colitis-Associated Colorectal Cancer Survival is Comparable to Sporadic Cases after Surgery: a Matched-Pair Analysis

BACKGROUND

Inflammatory bowel disease (IBD) confers an increased lifetime risk of colorectal cancer (CRC). The pathogenesis of colitis-associated CRC is considered distinct from sporadic CRC, but existing is mixed on long-term oncologic outcomes. This study aims to compare clinicopathological characteristics and survival between colitis-associated and sporadic CRC.

METHODS

Data was retrospectively extracted and analyzed from a single institutional database of patients with surgically resected CRC between 2004 and 2015. Patients with IBD were identified as having colitis-associated CRC. The remainder were classified as sporadic CRC. Propensity score matching was performed. Univariate and survival analyses were carried out to estimate the differences between the two groups.

RESULTS

Of 2275 patients included in this analysis, 65 carried a diagnosis of IBD (2.9%, 33 Crohn's disease, 29 ulcerative colitis, 3 indeterminate colitis). Average age at CRC diagnosis was 62 years for colitis-associated CRC and 65 for sporadic CRC. The final propensity score matched cohort consisted of 65 colitis-associated and 130 sporadic CRC cases. Patients with colitis-associated CRC were more likely to undergo total proctocolectomy (p < 0.01) and had higher incidence of locoregional recurrence (p = 0.026) compared to sporadic CRC patients. There were no significant differences in time to recurrence, tumor grade, extramural vascular invasion, perineural invasion, or rate of R0 resections. Overall survival and disease-free survival did not differ between groups. On multiple Cox regression, IBD diagnosis was not a significant predictor of survival.

CONCLUSIONS

Patients with colitis-associated CRC who undergo surgical resection have comparable overall and disease-free survival to patients with sporadic CRC.

LRRK2 G2019S promotes the development of colon cancer via modulating intestinal inflammation

LRRK2 G2019S is the most prevalent variant associated with Parkinson's disease (PD), found in 1-3% of sporadic and 4-8% of familial PD cases. Intriguingly, emerging clinical studies have suggested that LRRK2 G2019S carriers have an increased risk of cancers including colorectal cancer. However, the underlying mechanisms of the positive correlation between LRRK2-G2019S and colorectal cancer remain unknown. Using a mouse model of colitis-associated cancer (CAC) and LRRK2 G2019S knockin (KI) mice, here we report that LRRK2 G2019S promotes the pathogenesis of colon cancer as evidenced by increased tumor number and tumor size in LRRK2 G2019S KI mice. LRRK2 G2019S promoted intestinal epithelial cell proliferation and inflammation within the tumor microenvironment. Mechanistically, we found that LRRK2 G2019S KI mice are more susceptible to dextran sulfate sodium (DSS)-induced colitis. Suppressing the kinase activity of LRRK2 ameliorated the severity of colitis in both LRRK2 G2019S KI and WT mice. At the molecular level, our investigation unveiled that LRRK2 G2019S promotes the production of reactive oxygen species, triggers inflammasome activation, and induces cell necrosis in the gut epithelium in a mouse model of colitis. Collectively, our data provide direct evidence that gain-of-kinase activity in LRRK2 promotes colorectal tumorigenesis, implicating LRRK2 as a potential target in colon cancer patients with hyper LRRK2 kinase activity.

The Efficacy and Mechanism of Qinghua Jianpi Recipe in Inhibiting Canceration of Colorectal Adenoma Based on Inflammatory Cancer Transformation

Objective

This study is aimed at exploring the effect of Qinghua Jianpi Recipe on preventing colon polyp recurrence and inhibiting the progress of "inflammatory cancer transformation." And another goal is to explore the changes of intestinal flora structure and intestinal inflammatory (immune) microenvironment of mice with colon polyps treated by Qinghua Jianpi Recipe and to clarify its mechanism.

Methods

Clinical trials were conducted to confirm the therapeutic effect of Qinghua Jianpi Recipe on patients with inflammatory bowel disease. The inhibitory effect of Qinghua Jianpi Recipe on "inflammatory cancer transformation" of colon cancer was confirmed by an adenoma canceration mouse model. Histopathological examination was used to evaluate the effects of Qinghua Jianpi Recipe on intestinal inflammatory state, adenoma number, and pathological changes of adenoma model mice. The changes of inflammatory indexes in intestinal tissue were tested by ELISA. Intestinal flora was detected by 16S rRNA high-throughput sequencing. Short-chain fatty acid metabolism in the intestine was analyzed by targeted metabolomics. Network pharmacology analysis of possible mechanism of Qinghua Jianpi Recipe on colorectal cancer was performed. Western blot was used to detect the protein expression of the related signaling pathways.

Results

Qinghua Jianpi Recipe can significantly improve intestinal inflammation status and function in patients with inflammatory bowel disease. Qinghua Jianpi Recipe could significantly improve the intestinal inflammatory activity and pathological damage of adenoma model mice and reduce the number of adenoma. Qinghua Jianpi Recipe significantly increased the levels of Peptostreptococcales_Tissierellales, NK4A214_group, Romboutsia, and other intestinal flora after intervention. Meanwhile, the treatment group of Qinghua Jianpi Recipe could reverse the changes of short-chain fatty acids. Network pharmacology analysis and experimental studies showed that Qinghua Jianpi Recipe inhibited the "inflammatory cancer transformation" of colon cancer by regulating intestinal barrier function-related proteins, inflammatory and immune-related signaling pathways, and free fatty acid receptor 2 (FFAR2).

Conclusion

Qinghua Jianpi Recipe can improve the intestinal inflammatory activity and pathological damage of patient and adenoma cancer model mice. And its mechanism is related to the regulation of intestinal flora structure and abundance, short-chain fatty acid metabolism, intestinal barrier function, and inflammatory pathways.

Cancer in Inflammatory Bowel Disease

Inflammatory bowel diseases (IBD), including Crohn disease and ulcerative colitis, are chronic inflammatory conditions of the gastrointestinal tract. Individuals with IBD are at increased risk for several malignancies originating in the intestine, such as colorectal cancer, small bowel adenocarcinoma, intestinal lymphoma, and anal cancer. There are also several extraintestinal malignancies associated with IBD and IBD therapies, including cholangiocarcinoma, skin cancer, hematologic malignancies, genitourinary cancer, cervical cancer, and prostate cancer. The authors summarize the risk of cancer in patients with IBD, diagnosis and management of colorectal neoplasia in IBD, and management of patients with IBD and active or recent cancer.

A mendelian randomization study with populations of European ancestry rules out a causal relationship between inflammatory bowel disease and colorectal cancer

Background: Ulcerative colitis (UC), a subtype of inflammatory bowel disease (IBD), has been found to be associated with colorectal cancer (CRC) in observational studies, but there is no evidence to support a causal relationship or reverse causality between the two diseases.

Methods: We employed two-sample bidirectional Mendelian randomization to estimate an unconfounded bidirectional causal relationship between IBD (including UC and Crohn’s disease (CD)) and colorectal cancer. After searching IEU GWAS database and filtering SNPs, we applied a variety of MR methods including IVW method using qualified instrumental variables, and conducted sensitivity analysis to detect the heterogeneity and pleiotropy of instrumental variables.

Results: After using three groups of SNPs (CD: 106, UC: 113, IBD: 70), the IVW method MR analysis showed that the results were not significant (result for UC: odds ratio (OR) [95% Confidence Interval (CI)]: 0.9998 [0.9991–1.0005], p value: 0.58; result for CD: OR [95%CI]: 0.99962 [0.99912–1.00012], p value: 0.14; results for IBD: OR [95%CI]: 0.99959 [0.99869–1.00048], p value: 0.36). MR-Egger regression, WM method and MR-RAPS method reached the same conclusion. Sensitivity analysis did not reveal heterogeneity and pleiotropy. Bidirectional MR analysis was performed using the same procedure, and the results of IVW MR analysis were also not significant (result for CD: OR [95%CI]: 1.07985 [0.00049–2372.38304], p value 0.98; result for UC: OR [95%CI]: 0.27117 [0.00014–528.3707], p value: 0.74; result for IBD: OR [95%CI]: 0.47101 [0.0001–2242.94159], p value: 0.86). MR-Egger regression, WM method and MR-RAPS method also reached the same conclusion. Sensitivity analysis did not find any evidence of heterogeneity and pleiotropy.

Conclusion: Contrary to the conclusions of previous observational studies, a two-sample MR analysis did not find a causal relationship or reverse causal relationship between IBD and CRC. Sporadic CRC (sCRC) may differ in pathogenesis from IBD-related CRC.

Bringing to Light the Risk of Colorectal Cancer in Inflammatory Bowel Disease: Mucosal Glycosylation as a Key Player

Colitis-associated cancer is a major complication of inflammatory bowel disease remaining an important clinical challenge in terms of diagnosis, screening, and prognosis. Inflammation is a driving factor both in inflammatory bowel disease and cancer, but the mechanism underlying the transition from colon inflammation to cancer remains to be defined. Dysregulation of mucosal glycosylation has been described as a key regulatory mechanism associated both with colon inflammation and colorectal cancer development. In this review, we discuss the major molecular mechanisms of colitis-associated cancer pathogenesis, highlighting the role of glycans expressed at gut epithelial cells, at lamina propria T cells, and in serum proteins in the regulation of intestinal inflammation and its progression to colon cancer, further discussing its potential clinical and therapeutic applications.

Advances in Understanding Early-Onset Colorectal Cancer

Since the 1990s, the incidence of early-onset colorectal cancer (at <50 years of age) in the US has increased by more than 50%; similar increases have also been observed internationally. These increases are found particularly among individuals born during and after the 1960s, raising the possibility that the increased rates of early-onset colorectal cancer are attributable to changes in risk-factor patterns throughout successive generations. The reasons for these alarming epidemiologic patterns for early-onset colorectal cancer worldwide are only recently being investigated and major gaps in our knowledge remain. In the current issue of this journal, Arif and colleagues differentiated characteristics and outcomes of early-onset colorectal cancer in patients with the predisposing conditions of inflammatory bowel disease or hereditary genetic syndromes, compared with patients who have sporadic disease. Also, in this issue, Schumacher and colleagues investigated risk factors for early-onset colorectal adenocarcinoma in a nested case-control study among Kaiser Permanente Southern California (KPSC) health plan members. The research presented on characteristics and outcomes points to the importance of sporadic disease in the rise of early-onset colorectal cancer, while the research presented on risk factors points to the importance of obesity as a potential explanatory factor for this rise.See related articles by Arif et al., p. 1785 and by Schumacher et al., p. 1792.

Genetic and Epigenetic Characteristics of Inflammatory Bowel Disease-Associated Colorectal Cancer

BACKGROUND & AIMS

Inflammatory bowel disease (IBD) is a chronic, relapsing inflammatory disorder associated with an elevated risk of colorectal cancer (CRC). IBD-associated CRC (IBD-CRC) may represent a distinct pathway of tumorigenesis compared to sporadic CRC (sCRC). Our aim was to comprehensively characterize IBD-associated tumorigenesis integrating multiple high-throughput approaches, and to compare the results with in-house data sets from sCRCs.

METHODS

Whole-genome sequencing, single nucleotide polymorphism arrays, RNA sequencing, genome-wide methylation analysis, and immunohistochemistry were performed using fresh-frozen and formalin-fixed tissue samples of tumor and corresponding normal tissues from 31 patients with IBD-CRC.

RESULTS

Transcriptome-based tumor subtyping revealed the complete absence of canonical epithelial tumor subtype associated with WNT signaling in IBD-CRCs, dominated instead by mesenchymal stroma-rich subtype. Negative WNT regulators AXIN2 and RNF43 were strongly down-regulated in IBD-CRCs and chromosomal gains at HNF4A, a negative regulator of WNT-induced epithelial-mesenchymal transition (EMT), were less frequent compared to sCRCs. Enrichment of hypomethylation at HNF4α binding sites was detected solely in sCRC genomes. PIGR and OSMR involved in mucosal immunity were dysregulated via epigenetic modifications in IBD-CRCs. Genome-wide analysis showed significant enrichment of noncoding mutations to 5'untranslated region of TP53 in IBD-CRCs. As reported previously, somatic mutations in APC and KRAS were less frequent in IBD-CRCs compared to sCRCs.

CONCLUSIONS

Distinct mechanisms of WNT pathway dysregulation skew IBD-CRCs toward mesenchymal tumor subtype, which may affect prognosis and treatment options. Increased OSMR signaling may favor the establishment of mesenchymal tumors in patients with IBD.

Hereditary and Inflammatory Bowel Disease-Related Early Onset Colorectal Cancer Have Unique Characteristics and Clinical Course Compared with Sporadic Disease

BACKGROUND

Early onset colorectal cancer (EoCRC), diagnosed in those <50 years old, is increasing in incidence. We sought to differentiate characteristics and outcomes of EoCRC in patients with sporadic disease or preexisting conditions.

METHODS

We evaluated 2,135 patients with EoCRC in a population-based cohort from the Canadian province of British Columbia. Patients were identified on the basis of presence of hereditary syndromes (n = 146) or inflammatory bowel disease (IBD; n = 87) and compared with patients with sporadic EoCRC (n = 1,902).

RESULTS

Proportions of patients with preexisting conditions were highest in the youngest decile of 18-29 (34.3%, P < 0.0001). Patients with sporadic EoCRC were older, more likely female, and had increased BMI (P < 0.05). IBD-related EoCRC had the highest rates of metastatic disease, poor differentiation, adverse histology, lymphovascular, and perineural invasion (P < 0.05). Survival was lower in patients with IBD (HR, 1.80; 95% CI, 1.54-3.13; P < 0.0001) and higher in hereditary EoCRC (HR, 0.47; 95% CI, 0.45-0.73; P < 0.0001) compared with sporadic. Prognosis did not differ between ulcerative colitis or Crohn's disease but was lower in those with undifferentiated-IBD (HR, 1.87; 95% CI, 1.01-4.05; P = 0.049). Lynch syndrome EoCRC had improved survival over familial adenomatous polyposis (HR, 0.31; 95% CI, 0.054-0.57; P = 0.0037) and other syndromes (HR, 0.43; 95% CI, 0.11-0.99; P = 0.049). In multivariate analysis controlling for prognostic factors, hereditary EoCRC was unchanged from sporadic; however, IBD-related EoCRC had worse overall survival (HR, 2.21; 95% CI, 1.55-3.16; P < 0.0001).

CONCLUSIONS

EoCRC is heterogenous and patients with preexisting conditions have different characteristics and outcomes compared with sporadic disease.

IMPACT

Prognostic differences identified here for young patients with colorectal cancer and predisposing conditions may help facilitate treatment planning and patient counseling.See related commentary by Hayes, p. xxx.

From inflammation to colitis-associated colorectal cancer in inflammatory bowel disease: Pathogenesis and impact of current therapies

The risk of colorectal cancer (CRC) is higher in patients with inflammatory bowel disease (IBD). Population-based data from patients with ulcerative colitis (UC) estimate that the risk of CRC is approximately 2- to 3-fold that of the general population; patients with Crohn's disease appear to have a similar increased risk. However, the true extent of colitis-associated cancer (CAC) in undertreated IBD is unclear. Data suggest that the size (i.e., severity and extent) and persistence of the inflammatory process is largely responsible for the development of CRC in IBD. As patients with IBD and CRC have a worse prognosis than those without a history of IBD, the impact of current therapies for IBD on CAC is of importance. Chronic inflammation of the gut has been shown to increase the risk of developing CAC in both UC and CD. Therefore, control of inflammation is pivotal to the prevention of CAC. This review presents an overview of the current knowledge of CAC in IBD patients, focusing on the role of inflammation in the pathogenesis of CAC and the potential for IBD drugs to interfere with the process of carcinogenesis by reducing the inflammatory process or by modulating pathways directly involved in carcinogenesis.

Challenges in Crohn's Disease Management after Gastrointestinal Cancer Diagnosis

Simple Summary

Crohn’s disease (CD) is a chronic inflammatory bowel disease affecting both young and elderly patients, involving the entire gastrointestinal tract from the mouth to anus. The chronic transmural inflammation can lead to several complications, among which gastrointestinal cancers represent one of the most life-threatening, with a higher risk of onset as compared to the general population. Moreover, diagnostic and therapeutic strategies in this subset of patients still represent a significant challenge for physicians. Thus, the aim of this review is to provide a comprehensive overview of the current evidence for an adequate diagnostic pathway and medical and surgical management of CD patients after gastrointestinal cancer onset.

Abstract

Crohn’s disease (CD) is a chronic inflammatory bowel disease with a progressive course, potentially affecting the entire gastrointestinal tract from mouth to anus. Several studies have shown an increased risk of both intestinal and extra-intestinal cancer in patients with CD, due to long-standing transmural inflammation and damage accumulation. The similarity of symptoms among CD, its related complications and the de novo onset of gastrointestinal cancer raises difficulties in the differential diagnosis. In addition, once a cancer diagnosis in CD patients is made, selecting the appropriate treatment can be particularly challenging. Indeed, both surgical and oncological treatments are not always the same as that of the general population, due to the inflammatory context of the gastrointestinal tract and the potential exacerbation of gastrointestinal symptoms of patients with CD; moreover, the overlap of the neoplastic disease could lead to adjustments in the pharmacological treatment of the underlying CD, especially with regard to immunosuppressive drugs. For these reasons, a case-by-case analysis in a multidisciplinary approach is often appropriate for the best diagnostic and therapeutic evaluation of patients with CD after gastrointestinal cancer onset.

Colon Carcinogenesis: The Interplay Between Diet and Gut Microbiota

Colorectal cancer (CRC) incidence increases yearly, and is three to four times higher in developed countries compared to developing countries. The well-known risk factors have been attributed to low physical activity, overweight, obesity, dietary consumption including excessive consumption of red processed meats, alcohol, and low dietary fiber content. There is growing evidence of the interplay between diet and gut microbiota in CRC carcinogenesis. Although there appears to be a direct causal role for gut microbes in the development of CRC in some animal models, the link between diet, gut microbes, and colonic carcinogenesis has been established largely as an association rather than as a cause-and-effect relationship. This is especially true for human studies. As essential dietary factors influence CRC risk, the role of proteins, carbohydrates, fat, and their end products are considered as part of the interplay between diet and gut microbiota. The underlying molecular mechanisms of colon carcinogenesis mediated by gut microbiota are also discussed. Human biological responses such as inflammation, oxidative stress, deoxyribonucleic acid (DNA) damage can all influence dysbiosis and consequently CRC carcinogenesis. Dysbiosis could add to CRC risk by shifting the effect of dietary components toward promoting a colonic neoplasm together with interacting with gut microbiota. It follows that dietary intervention and gut microbiota modulation may play a vital role in reducing CRC risk.

Colorectal Cancer in Inflammatory Bowel Disease

Patients with inflammatory bowel disease (IBD) are at an increased risk for developing colorectal cancer (CRC). However, the incidence has declined over the past 30 years, which is probably attributed to raise awareness, successful CRC surveillance programs and improved control of mucosal inflammation through chemoprevention. The risk factors for IBD-related CRC include more severe disease (as reflected by the extent of disease and the duration of poorly controlled disease), family history of CRC, pseudo polyps, primary sclerosing cholangitis, and male sex. The molecular pathogenesis of inflammatory epithelium might play a critical role in the development of CRC. IBD-related CRC is characterized by fewer rectal tumors, more synchronous and poorly differentiated tumors compared with sporadic cancers. There is no significant difference in sex distribution, stage at presentation, or survival. Surveillance is vital for the detection and subsequently management of dysplasia. Most guidelines recommend initiation of surveillance colonoscopy at 8 to 10 years after IBD diagnosis, followed by subsequent surveillance of 1 to 2 yearly intervals. Traditionally, surveillance colonoscopies with random colonic biopsies were used. However, recent data suggest that high definition and chromoendoscopy are better methods of surveillance by improving sensitivity to previously "invisible" flat dysplastic lesions. Management of dysplasia, timing of surveillance, chemoprevention, and the surgical approaches are all areas that stimulate various discussions. The aim of this review is to provide an up-to-date focus on CRC in IBD, from laboratory to bedside.

Risk of Development of More-advanced Lesions in Patients With Inflammatory Bowel Diseases and Dysplasia

BACKGROUND & AIMS

Patients with inflammatory bowel diseases (IBD) have increased risks of dysplasia and colitis-associated cancer (CAC). We evaluated the risk of development of high-grade dysplasia (HGD) or CAC after diagnosis of dysplasia using data from a national cohort of patients with IBD.

METHODS

We performed a multicenter retrospective analysis of data collected from 7 tertiary referral regional or academic centers in Belgium. In searches of IBD pathology databases, we identified 813 lesions (616 low-grade dysplasias [LGDs], 64 high-grade dysplasias [HGDs], and 133 CACs) in 410 patients with IBD: 299 had dysplasia (73%) and 111 had CAC (27%). The primary aim was to determine the risk of more-advanced lesions after diagnosis of LGD or HGD.

RESULTS

Of the 287 patients with LGD, 21 (7%) developed more-advanced lesions (HGD or CAC) after a median time period of 86 months (interquartile range, 34-214). Of the 28 patients with HGD, 4 (14%) developed CAC after a median time period of 180 months (interquartile range, 23-444). The overall cumulative incidence of CAC at 10 years after an initial diagnosis of HGD was 24.3% and after an initial diagnosis of LGD was 8.5% (P < .05). Metachronous lesions, non-polypoid lesions, and colonic stricture were associated with risk of occurrence of more-advanced lesions after LGD (P < .05). Of the 630 dysplastic lesions identified during endoscopy, 545 (86%) were removed during the same procedure or during a follow-up endoscopy or by surgery. Of 111 patients with CAC, 95 (86%) did not have prior detection of dysplasia and 64 of these 95 patients (67%) developed CAC outside of the screening or surveillance period recommended by the European Crohn's and Colitis Organisation.

CONCLUSIONS

In an analysis of pathology data from 7 medical centers in Belgium, we found a low rate of detection of more-advanced lesions following detection of LGD or HGD-taking into account that most of the lesions were removed. Main risk factors for development of more-advanced lesions after LGD were metachronous lesions, non-polypoid lesions, and colon strictures.

Sex-based differences in inflammatory bowel diseases: a review

Sex-based differences in inflammatory bowel disease (IBD) pathogenesis, disease course, and response to therapy have been increasingly recognized, however, not fully understood. Experimental and translational models have been leveraged to investigate hypothesized mechanisms for these observed differences, including the potential modifying role of sex hormones and sex-dependent (epi)genetic and gut microbiome changes. The primary objective of this review is to comprehensively describe sex-based differences in IBD including epidemiology, pathogenesis, phenotypic differences, therapeutic response, and outcomes.

Gastrointestinal neoplasia in patients with inflammatory bowel disease: Opportunities to enhance preventative strategies

Background and Aims

Gastrointestinal (GI) adenocarcinoma, especially colorectal cancer (CRC), is a devastating complication of inflammatory bowel disease (IBD). We sought to examine the role of chronic inflammation and other possible predictors of the development of CRC, as well as assess as yet unexamined factors such as psychological comorbidity and engagement in care.

Methods

This study included all patients involved in a tertiary hospital IBD service diagnosed with CRC between 2007 and 2017. Reports from histological specimens were assessed, and all those with adenocarcinoma, high‐grade dysplasia (HGD), or multifocal low‐grade dysplasia (LGD) originating within IBD‐affected mucosa were included in the study.

Results

A total of 32 patients were included in the study (17 with adenocarcinoma and 15 with HGD/multifocal LGD). The majority had a duration of disease >20 years. Eleven patients (34%, CI 20–52%) had previous disease‐related surgery, and 16 (50%, CI 34–66%) had multiple previous disease‐related admissions. Thirteen patients (62%, CI 41–79%) had >50% of CRP results higher than 8 mg/L. Psychiatric comorbidities were common, with 19 patients (59%, CI 42–74%) having a psychiatric comorbidity or poor engagement in treatment.

Conclusion

In this cohort, we have highlighted poor engagement, hesitation to up‐titrate therapy when indicated, and psychological comorbidities as likely contributors to poor disease control and development of GI adenocarcinoma. Based on our data, these easily identifiable clinical care factors should not be overlooked when addressing IBD‐related GI malignancy prevention. Additional research is required to assess a direct causal relationship, but this study would support the incorporation of psychology services into IBD clinics.

Age-Related Survival Differences in Patients With Inflammatory Bowel Disease-Associated Colorectal Cancer: A Population-Based Cohort Study

BACKGROUND

Reported outcomes for colorectal cancer associated with inflammatory bowel disease are inconsistent. We compared survival outcomes in colorectal cancer patients with and without inflammatory bowel disease using a population-based cohort and elicited prognostic factors associated with survival.

METHODS

Adult patients with a diagnosis of colorectal cancer in 2007-2015 were identified from the Ontario Cancer Registry. Those with inflammatory bowel disease (IBD) were detected via the validated Ontario Crohn's and Colitis Cohort. The primary outcome measure was overall survival from time of colorectal cancer diagnosis until the date of death. Secondary outcome measures included treatments received and publicly provided health care costs.

RESULTS

Colorectal cancer was diagnosed in 67,137, with inflammatory bowel disease present in 783 (1.2%). The IBD-associated colorectal cancer patients were younger at diagnosis (median range, 55-59 vs 70-74 years; P < 0.001). Five-year survival in IBD-associated patients was 56.4% (95% confidence interval [CI], 52.6%-59.9%) and 57.0% (95% CI, 56.6%-57.4%) in sporadic colorectal cancer (P = 0.8). Inflammatory bowel disease was a significant predictor of death (hazard ratio, 1.45; 95% CI, 1.29-1.63; P < 0.001) after adjusting for other variables. In patients under 50, 5-year survival was significantly (P < 0.001) reduced in the IBD population (56.8%; 95% CI, 49.4%-63.5%) compared with the sporadic colorectal cancer population (71.4%; 95% CI, 70.0%-72.7%). Similar results were observed in those 50-64 years old.

CONCLUSIONS

Patients with IBD-associated CRC appear to have worse survival than those with sporadic CRC. In subgroups based on age, this difference appears to be driven by young (<65 years old) patients with IBD. These findings may direct future research on treatment for this high-risk population.

Role of Fecal Diversion in Complex Crohn's Disease

Crohn's disease (CD) is a chronic inflammatory condition of the gastrointestinal tract resulting in progressive tissue damage, which can result in strictures, fistulae, and abscesses formation. The triggering mechanism is thought to be in the fecal stream, and diversion of this fecal stream is sometimes required to control disease when all other avenues of medical and surgical management have been exhausted. Fecal diversion can be temporary or permanent with the indications being defunctioning a high-risk anastomosis, as a result of a surgical complication, for disease control, or due to severe colonic, rectal, or perianal disease. The incidence of ostomy formation in CD has increased epidemiologically over time. The primary indication for ostomy formation is severe perianal fistulizing disease. However, while 64% of patients have an early clinical response after diversion for refractory perianal CD, restoration of bowel continuity is attempted in only 35% of patients, and is successful in only 17%. The current review discusses the indications for ostomy creation in complex CD, strategies for procedure selection, and patient outcomes.

Colorectal cancer in inflammatory bowel disease: review of the evidence

Inflammatory bowel disease (IBD)-related colorectal cancer (CRC) is responsible for approximately 2% of the annual mortality from CRC overall, but 10-15% of the annual deaths in IBD patients. IBD-related CRC patients are also affected at a younger age than sporadic CRC patients, and have a 5-year survival rate of 50%. Despite optimal medical treatment, the chronic inflammatory state inherent in IBD increases the risk for high-grade dysplasia and CRC, with additional input from genetic and environmental risk factors and the microbiome. Recognizing risk factors, implementing appropriate surveillance, and identifying high-risk patients are key to managing the CRC risk in IBD patients. Chemoprevention strategies exist, and studies evaluating their efficacy are underway. Once dysplasia or invasive cancer is diagnosed, appropriate surgical resection and postoperative treatment and surveillance are necessary. Here, we discuss the current state of IBD-related CRC, prevalence, risk factors, and evidence for surveillance, prophylaxis, and treatment recommendations.

Mutational Analysis Identifies Therapeutic Biomarkers in Inflammatory Bowel Disease-Associated Colorectal Cancers

Purpose: Inflammatory bowel disease-associated colorectal cancers (IBD-CRC) are associated with a higher mortality than sporadic colorectal cancers. The poorly defined molecular pathogenesis of IBD-CRCs limits development of effective prevention, detection, and treatment strategies. We aimed to identify biomarkers using whole-exome sequencing of IBD-CRCs to guide individualized management.Experimental Design: Whole-exome sequencing was performed on 34 formalin-fixed paraffin-embedded primary IBD-CRCs and 31 matched normal lymph nodes. Computational methods were used to identify somatic point mutations, small insertions and deletions, mutational signatures, and somatic copy number alterations. Mismatch repair status was examined.Results: Hypermutation was observed in 27% of IBD-CRCs. All hypermutated cancers were from the proximal colon; all but one of the cancers with hypermutation had defective mismatch repair or somatic mutations in the proofreading domain of DNA POLE Hypermutated IBD-CRCs had increased numbers of predicted neo-epitopes, which could be exploited using immunotherapy. We identified six distinct mutation signatures in IBD-CRCs, three of which corresponded to known mechanisms of mutagenesis. Driver genes were also identified.Conclusions: IBD-CRCs should be evaluated for hypermutation and defective mismatch repair to identify patients with a higher neo-epitope load who may benefit from immunotherapies. Prospective trials are required to determine whether IHC to detect loss of MLH1 expression in dysplastic colonic tissue could identify patients at increased risk of developing IBD-CRC. We identified mutations in genes in IBD-CRCs with hypermutation that might be targeted therapeutically. These approaches would complement and individualize surveillance and treatment programs. Clin Cancer Res; 24(20); 5133-42. ©2018 AACR.

Vitamin D signaling in intestinal innate immunity and homeostasis

The lumen of the gut hosts a plethora of microorganisms that participate in food assimilation, inactivation of harmful particles and in vitamin synthesis. On the other hand, enteric flora, a number of food antigens, and toxins are capable of triggering immune responses causing inflammation, which, when unresolved, may lead to chronic conditions such as inflammatory bowel disease (IBD). It is important, therefore, to contain the gut bacteria within the lumen, control microbial load and composition, as well as ensure adequate innate and adaptive immune responses to pathogenic threats. There is growing evidence that vitamin D signaling has impacts on all these aspects of intestinal physiology, contributing to healthy enteric homeostasis. VD was first discovered as the curative agent for nutritional rickets, and its classical actions are associated with calcium absorption and bone health. However, vitamin D exhibits a number of extra-skeletal effects, particularly in innate immunity. Notably, it stimulates production of pattern recognition receptors, anti-microbial peptides, and cytokines, which are at the forefront of innate immune responses. They play a role in sensing the microbiota, in preventing excessive bacterial overgrowth, and complement the actions of vitamin D signaling in enhancing intestinal barrier function. Vitamin D also favours tolerogenic rather than inflammogenic T cell differentiation and function. Compromised innate immune function and overactive adaptive immunity, as well as defective intestinal barrier function, have been associated with IBD. Importantly, observational and intervention studies support a beneficial role of vitamin D supplementation in patients with Crohn's disease, a form of IBD. This review summarizes the effects of vitamin D signaling on barrier integrity and innate and adaptive immunity in the gut, as well as on microbial load and composition. Collectively, studies to date reveal that vitamin D signaling has widespread effects on gut homeostasis, and provide a mechanistic basis for potential therapeutic benefit of vitamin D supplementation in IBD.