Use of thiopurines and risk of colorectal neoplasia in patients with inflammatory bowel diseases: a meta-analysis

Colorectal Neoplasia in the Setting of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is associated with an increased risk of colorectal cancer (colorectal adenocarcinoma [CRC]) compared with the general population. IBD-related CRC is related to poorer outcomes than non-IBD-related CRC, and it accounts for 10% to 15% of death in patients with IBD. As such, screening guidelines have been made specific to this population recommending shorter intervals of endoscopic screening to detect dysplasia and CRC relative to the general population. Advances in endoscopic technology allow for improved visualization of dysplasia, which has led to widespread adoption of dye-spray chromoendoscopy with targeted biopsy.

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.

Interval Colorectal Cancer in Inflammatory Bowel Disease: A Review

Inflammatory bowel disease (IBD) increases the risk of dysplasia and colorectal cancer (CRC). Moreover, colitis-associated CRC is responsible for a disproportionate number of CRC-related mortality. For this reason, societies recommend screening and surveillance colonoscopy as the standard of care for patients with ulcerative colitis and Crohn's colitis. Nonetheless, interval cancer defined as CRC detected within the appropriate surveillance interval might still occur despite following guideline recommendations. Even though there is limited data on risk factors associated with interval CRC in IBD, patient and disease-associated factors and technical aspects of the surveillance might play a role. This review aims to provide information on the epidemiology of interval CRC in IBD, the factors that might be associated with its occurrence, and the challenges of CRC screening and dysplasia management in patients with IBD.

Inflammation-Driven Colorectal Cancer Associated with Colitis: From Pathogenesis to Changing Therapy

Patients affected by inflammatory bowel disease (IBD) have a two-fold higher risk of developing colorectal cancer (CRC) than the general population. IBD-related CRC follows a different genetic and molecular pathogenic pathway than sporadic CRC and can be considered a complication of chronic intestinal inflammation. Since inflammation is recognised as an independent risk factor for neoplastic progression, clinicians strive to modulate and control disease, often using potent therapy agents to achieve mucosal healing and decrease the risk of colorectal cancer in IBD patients. Improved therapeutic control of inflammation, combined with endoscopic advances and early detection of pre-cancerous lesions through surveillance programs, explains the lower incidence rate of IBD-related CRC. In addition, current research is increasingly focused on translating emerging and advanced knowledge in microbiome and metagenomics into personalised, early, and non-invasive CRC screening tools that guide organ-sparing therapy in IBD patients. This review aims to summarise the existing literature on IBD-associated CRC, focusing on new insights into the alteration of the intestinal barrier and the interactions with the gut microbiome as the initial promoter. In addition, the role of OMIC techniques for precision medicine and the impact of the available IBD therapeutic armamentarium on the evolution to CRC will be discussed.

Colorectal Cancer in Ulcerative Colitis: Mechanisms, Surveillance and Chemoprevention

Patients with ulcerative colitis (UC) are at a two- to three-fold increased risk of developing colorectal cancer (CRC) than the general population based on population-based data. UC-CRC has generated a series of clinical problems, which are reflected in its worse prognosis and higher mortality than sporadic CRC. Chronic inflammation is a significant contributor to the development of UC-CRC, so comprehending the relationship between the proinflammatory factors and epithelial cells together with downstream signaling pathways is the core to elucidate the mechanisms involved in developing of CRC. Clinical studies have shown the importance of early prevention, detection and management of CRC in patients with UC, and colonoscopic surveillance at regular intervals with multiple biopsies is considered the most effective way. The use of endoscopy with targeted biopsies of visible lesions has been supported in most populations. In contrast, random biopsies in patients with high-risk characteristics have been suggested during surveillance. Some of the agents used to treat UC are chemopreventive, the effects of which will be examined in cancers in UC in a population-based setting. In this review, we outline the current state of potential risk factors and chemopreventive recommendations in UC-CRC, with a specific focus on the proinflammatory mechanisms in promoting CRC and evidence for personalized surveillance.

Oral Conventional Synthetic Disease-Modifying Antirheumatic Drugs with Antineoplastic Potential: a Review

There is an increasing trend of malignancy worldwide. Disease-modifying antirheumatic drugs (DMARDs) are the cornerstones for the treatment of immune-mediated inflammatory diseases (IMIDs), but risk of malignancy is a major concern for patients receiving DMARDs. In addition, many IMIDs already carry higher background risks of neoplasms. Recently, the black box warning of malignancies has been added for Janus kinase inhibitors. Also, the use of biologic DMARDs in patients with established malignancies is usually discouraged owing to exclusion of such patients in pivotal studies and, hence, lack of evidence. In contrast, some conventional synthetic DMARDs (csDMARDs) have been reported to show antineoplastic properties and can be beneficial for patients with cancer. Among the csDMARDs, chloroquine and hydroxychloroquine have been the most extensively studied, and methotrexate is an established chemotherapeutic agent. Even cyclosporine A, a well-known drug associated with cancer risk, can potentiate the effect of some chemotherapeutic agents. We review the possible mechanisms behind and clinical evidence of the antineoplastic activities of csDMARDs, including chloroquine and hydroxychloroquine, cyclosporine, leflunomide, mycophenolate mofetil, mycophenolic acid, methotrexate, sulfasalazine, and thiopurines. This knowledge may guide physicians in the choice of csDMARDs for patients with concurrent IMIDs and malignancies.

Colorectal Cancer in Inflammatory Bowel Disease: Mechanisms and Management

Patients with inflammatory bowel disease (IBD) are at increased risk of developing colorectal cancer (CRC), despite decreases in CRC incidence in recent years. Chronic inflammation is the driver of neoplastic progression, resulting in dysplastic precursor lesions that may arise in multiple areas of the colon through a process of field cancerization. Colitis-associated CRC shares many molecular similarities with sporadic CRC, and preclinical investigations have demonstrated a potential role for the microbiome in concert with the host immune system in the development of colitis-associated colorectal cancer (CAC). Some unique molecular differences occur in CAC, but their role in the pathogenesis and behavior of inflammation-associated cancers remains to be elucidated. Nonconventional types of dysplasia have been increasingly recognized, but their natural history is not well defined, and they have not been incorporated into surveillance algorithms. The concept of cumulative inflammatory burden highlights the importance of considering histologic inflammation over time as an important risk factor for CAC. Dysplasia is arguably the most important risk factor for developing CAC, and advances have been made in the endoscopic detection and removal of precancerous lesions, thereby deferring or avoiding surgical resection. Some of the agents used to treat IBD are chemopreventive. It is hoped that by gaining better control of the underlying inflammation with newer medications and better endoscopic detection and management, a more sophisticated appreciation of clinicopathologic risk factors, and growing awareness of the genetic, immunologic, and environmental causes of colitis- associated neoplasia, that colitis-associated colorectal neoplasia will become even more predictable and manageable in the coming years.

5-Aminosalicylic Acid Chemoprevention in Inflammatory Bowel Diseases: Is It Necessary in the Age of Biologics and Small Molecules?

BACKGROUND

Due to the increased incidence of colorectal cancer in inflammatory bowel diseases (IBDs), the value of chemoprevention for this patient group has been repeatedly debated in the past decade. This review describes available evidence and the current recommendations for chemoprevention in national and international guidelines IBD guidelines.

SUMMARY

5-Aminosalicylic acid (5-ASA) compounds are the preferred therapeutic option for mild to moderate ulcerative colitis (UC). Aside from the known anti-inflammatory effects, their chemopreventive abilities have been described in vitro and in vivo. Pooling the increasing number of retrospective and population-based clinical studies over the last 15 years, 7 consecutive meta-analyses revealed partially conflicting results for the chemopreventive efficacy of 5-ASA, and thus, not all IBD guidelines currently recommend chemoprevention with mesalamine compounds. Accumulating evidence for decreasing the colorectal cancer (CRC) risk in support of thiopurines more recently shows a protective effect. This effect seems solely mediated by control of intestinal inflammation since, for this drug class, another mechanistic interference in IBD-associated CRC pathogenesis is not known. The results regarding chemopreventive efficacy for ursodeoxycholic acid or folic acid are equivocal, and the use of these medications to prevent CRC is not firmly established. Like UC, the risk of CRC is also significantly increased in patients with Crohn's disease (CD), especially Crohn's colitis. However, no published studies exclusively assess the effects of surveillance on the early detection of cancer or CRC chemoprevention in CD patients. In meta-analyses, which predominantly included UC patients, 5-ASA or thiopurines were not beneficial in small CD subgroups. The level of evidence for anti-TNFα agents, anti-integrin (e.g., vedolizumab), or anti-IL-12/IL-23 agents (e.g., ustekinumab) and Janus kinase inhibitors is currently too low or nonexistent to use them solely for chemoprevention in UC or CD patients.

KEY MESSAGE

Intestinal inflammation is one of the main risk factors for developing CRC in IBD, and all drugs that induce and maintain mucosal healing most likely also decrease the IBD-associated CRC risk. Thus, a therapeutic strategy of adding a 5-ASA therapy to a successfully mucosal healing-inducing therapy, for example, with a biologic or a small molecule merely to prevent CRC appears to be obsolete.

Factors Associated With Advanced Colorectal Neoplasia in Patients With CKD

RATIONALE & OBJECTIVE

The risk of developing colorectal cancer in patients with chronic kidney disease (CKD) is twice that of the general population, but the factors associated with colorectal cancer are poorly understood. The aim of this study was to identify factors associated with advanced colorectal neoplasia in patients with CKD.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

Patients with CKD stages 3-5, including those treated with maintenance dialysis or transplantation across 11 sites in Australia, New Zealand, Canada, and Spain, were screened for colorectal neoplasia using a fecal immunochemical test (FIT) as part of the Detecting Bowel Cancer in CKD (DETECT) Study.

EXPOSURE

Baseline characteristics for patients at the time of study enrollment were ascertained, including duration of CKD, comorbidities, and medications.

OUTCOME

Advanced colorectal neoplasia was identified through a 2-step verification process with colonoscopy following positive FIT and 2-year clinical follow-up for all patients.

ANALYTICAL APPROACH

Potential factors associated with advanced colorectal neoplasia were explored using multivariable logistic regression. Sensitivity analyses were performed using grouped LASSO (least absolute shrinkage and selection operator) logistic regression.

RESULTS

Among 1,706 patients who received FIT-based screening-791 with CKD stages 3-5 not receiving kidney replacement therapy (KRT), 418 receiving dialysis, and 497 patients with a functioning kidney transplant-117 patients (6.9%) were detected to have advanced colorectal neoplasia (54 with CKD stages 3-5 without KRT, 34 receiving dialysis, and 29 transplant recipients), including 9 colorectal cancers. The factors found to be associated with advanced colorectal neoplasia included older age (OR per year older, 1.05 [95% CI, 1.03-1.07], P<0.001), male sex (OR, 2.27 [95% CI, 1.45-3.54], P<0.001), azathioprine use (OR, 2.99 [95% CI, 1.40-6.37], P=0.005), and erythropoiesis-stimulating agent use (OR, 1.92 [95% CI, 1.22-3.03], P=0.005). Grouped LASSO logistic regression revealed similar associations between these factors and advanced colorectal neoplasia.

LIMITATIONS

Unmeasured confounding factors.

CONCLUSIONS

Older age, male sex, erythropoiesis-stimulating agents, and azathioprine were found to be significantly associated with advanced colorectal neoplasia in patients with CKD.

Heterogeneity of Colorectal Cancer Progression: Molecular Gas and Brakes

The review begins with molecular genetics, which hit the field unveiling the involvement of oncogenes and tumor suppressor genes in the pathogenesis of colorectal cancer (CRC) and uncovering genetic predispositions. Then the notion of molecular phenotypes with different clinical behaviors was introduced and translated in the clinical arena, paving the way to next-generation sequencing that captured previously unrecognized heterogeneity. Among other molecular regulators of CRC progression, the extent of host immune response within the tumor micro-environment has a critical position. Translational sciences deeply investigated the field, accelerating the pace toward clinical transition, due to its strong association with outcomes. While the perturbation of gut homeostasis occurring in inflammatory bowel diseases can fuel carcinogenesis, micronutrients like vitamin D and calcium can act as brakes, and we discuss underlying molecular mechanisms. Among the components of gut microbiota, Fusobacterium nucleatum is over-represented in CRC, and may worsen patient outcome. However, any translational knowledge tracing the multifaceted evolution of CRC should be interpreted according to the prognostic and predictive frame of the TNM-staging system in a perspective of clinical actionability. Eventually, we examine challenges and promises of pharmacological interventions aimed to restrain disease progression at different disease stages.

Risk of skin cancers in thiopurines-treated and thiopurines-untreated patients with inflammatory bowel disease: A systematic review and meta-analysis

BACKGROUND AND AIM

The thiopurines are effective in the management of patients with inflammatory bowel disease (IBD), but the association between thiopurines use and the risk of skin cancer (including nonmelanoma skin cancer [NMSC] and melanoma skin cancer) has already been sufficiently reported. However, the results of these studies are inconsistent, and thus, the objective of our analysis was to explore whether thiopurines can lead to an excess risk of skin cancer in IBD patients.

METHODS

MEDLINE, EMBASE, and the Cochrane Library were searched to identify relevant studies that evaluated the risk of skin cancer in IBD patients treated with thiopurines. A random effects meta-analysis was conducted to calculate the pooled incidence rate ratios as well as risk ratios (RRs). Subgroup analysis was performed to explore the potential source of heterogeneity.

RESULTS

Thirteen studies comprising 149 198 participants were included. The result suggested that thiopurines significantly increased the risk of overall skin cancer in IBD patients (random effects: RR = 1.80, 95% confidence interval [CI] 1.14-2.87, P = 0.013), among which NMSC showed an excess risk associated with thiopurines use (random effects: RR = 1.88, 95% CI 1.48-2.38, P < 0.001) while no increased risk was observed with respect to melanoma skin cancer (random effects: RR = 1.22, 95% CI 0.90-1.65, P = 0.206). Subgroup analysis regarding sample size and geographic distribution in skin cancer and follow-up duration in NMSC reached statistical significance, while other subgroups showed no significance.

CONCLUSION

Exposition of thiopurines in patients with IBD is associated with a higher risk of skin cancer. Routine skin screening and daily skin protective practice are recommended for these patients.

Malignancies in Inflammatory Bowel Disease: Frequency, Incidence and Risk Factors-Results from the Swiss IBD Cohort Study

BACKGROUND

Malignancy may occur as long-term complication of inflammatory bowel disease (IBD) due to different risk factors. We assessed prevalence and incidence of malignancy, and predictive factors in the Swiss IBD Cohort Study (SIBDCS).

METHODS

All IBD patients in the SIBDCS were analyzed from a cross-sectional and longitudinal perspective. Patients with malignancies were compared to controls. Standardized incidence ratios (SIR) were calculated based on age-specific and sex-specific background rates.

RESULTS

Malignancies were identified in 122 of 3119 patients (3.9%). In a logistic regression model, age (OR 1.04 per year), intestinal surgery (OR 3.34), and treatment with steroids (OR 2.10) were the main predictors for the presence of malignancy, while treatment with 5-ASA (OR 0.57) and biologics (OR 0.38) were protective. From a longitudinal perspective, 67 out of 2580 patients (2.6%) were newly diagnosed with malignancy during a follow-up of 12,420.8 years (median 4.9 years). While there was no increased risk for malignancy overall (SIR 0.93, 95% CI 0.72-1.18) and colorectal cancer (SIR 1.55, 95% CI 0.71-2.95), IBD patients had an increased risk for lymphoma (SIR 2.98, 95% CI 1.36-5.66) and biliary cancer (SIR 6.3, 95% CI 1.27-18.41). In a Cox regression model, age and recent use of immunomodulators were the main predictors for development of malignancies, while 5-ASA, biologics were protective.

CONCLUSIONS

IBD patients showed increased risk for lymphoma and biliary cancer, but not colorectal cancer and cancer overall. Age and recent use of immunomodulators were the main risk factors for malignancy, while aminosalicylates and biologics appear to be protective.

Colorectal Cancer in Inflammatory Bowel Disease

Patients with inflammatory bowel disease (IBD) are at significantly increased risk of colorectal cancer (CRC), principally resulting from the pro-neoplastic effects of chronic intestinal inflammation. Epidemiologic studies continue to highlight the increased risk of CRC in IBD. However, the incidence has declined over the past 30 years, attributed to both successful CRC-surveillance programs and improved control of mucosal inflammation. Risk factors that further increase the risk of IBD-related CRC include disease duration, extent and severity, the presence of inflammatory pseudopolyps, coexistent primary sclerosing cholangitis, and a family history of CRC. All major professional societies agree that IBD-CRC surveillance should occur more frequently than in the general population. Yet, guidelines and consensus statements differ on the surveillance schedule and preferred method of surveillance. Improved sensitivity to previously "invisible" flat dysplastic lesions using high definition and chromoendoscopy methods has resulted in many guidelines abandoning requirements for random untargeted biopsies of the colon. While colonic dysplasia remains a worrisome finding, and several clinical scenarios remain best addressed by total proctocolectomy due to concerns of synchronous undetected lesions and the unpredictable tempo of progression to malignancy, better detection techniques have also increased opportunities for endoscopic resection of dysplastic lesions that can be clearly delineated. Finally, the expanding armamentarium of medical options in IBD, including anti-tumor necrosis factor and anti-adhesion biologic therapies, have substantially improved our ability to control severe inflammation and likely reduce the risk of CRC over time.

Reduced Risk of Inflammatory Bowel Disease-associated Colorectal Neoplasia with Use of Thiopurines: a Systematic Review and Meta-analysis

BACKGROUND AND AIMS

The association between thiopurines and colorectal neoplasia risk remains controversial in inflammatory bowel disease [IBD] patients. We performed a systematic review and meta-analysis examining this association.

METHODS

A comprehensive search of the PubMed, EMBASE and Cochrane Library databases was performed to identify relevant literature. Random-effects models were applied to calculate the pooled odds ratio [OR] and relative risk [RR] with corresponding 95% confidence intervals [CIs] among case-control and cohort studies.

RESULTS

Eleven cohort and 16 case-control studies involving 95397 patients were included in this study. Overall, the use of thiopurines was associated with a reduced risk of colorectal neoplasia both in case-control [OR = 0.49, 95% CI: 0.34-0.70] and cohort studies [RR = 0.96, 95% CI: 0.94-0.98]. Moreover, a protective effect of thiopurines against advanced neoplasia [high-grade dysplasia and cancer] [OR = 0.51, 95% CI: 0.31-0.84 for case-control studies; RR = 0.96, 95% CI: 0.94-0.98 for cohort studies] and colorectal cancer [CRC] [OR = 0.56, 95% CI: 0.34-0.93 for case-control studies; RR = 0.96, 95% CI: 0.94-0.98 for cohort studies] was also observed. Furthermore, when the analysis was conducted on patients at a high risk for colorectal neoplasia, the chemopreventive effect was confirmed in patients with long disease duration [> 8 years] but not in those with extensive colitis or primary sclerosing cholangitis.

CONCLUSIONS

This study demonstrated that thiopurine use was associated with a reduced risk of colorectal neoplasia, advanced neoplasia and CRC in IBD patients, especially those with long disease duration [> 8 years].

Systematic review with meta-analysis: thiopurines decrease the risk of colorectal neoplasia in patients with inflammatory bowel disease

BACKGROUND

Patients with inflammatory bowel disease (IBD) have a high risk of developing colorectal neoplasia.

AIM

To investigate whether thiopurines can decrease the risk of developing colorectal neoplasia in patients with ulcerative colitis (UC) or Crohn's disease (CD).

METHODS

We conducted a meta-analysis of 24 observational studies involving 76,999 participants to evaluate the risks of developing colorectal neoplasia in IBD patients receiving thiopurine treatment. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) for the risks of colorectal neoplasia were calculated using a random-effects model.

RESULTS

The overall pooled estimate revealed a protective effect of thiopurine use on colorectal neoplasia in patients with IBD (OR = 0.63, 95% CI 0.46-0.86). The effect was significant in UC patients (OR = 0.67, 95% CI 0.45-0.98), but was not significant in CD patients (OR = 1.06, 95% CI 0.54-2.09). Thiopurines exposure significantly decreased the risk of colorectal cancer (CRC) (OR = 0.65, 95% CI 0.45-0.96) and advanced colorectal neoplasia (CRC and/or high-grade dysplasia) (OR = 0.62, 95% CI 0.44-0.89), but did not decrease the risk of dysplasia alone (OR = 0.90, 95% CI 0.37-2.21). Tendencies towards the protective effect of thiopurines were distinct in clinic-based studies (OR = 0.59, 95% CI 0.42-0.82) and case-control studies (OR = 0.40, 95% CI 0.26-0.62), but not in population-based studies (OR = 0.95, 95% CI 0.55-1.62) and cohort studies (OR = 0.98, 95% CI 0.81-1.18). Interestingly, studies conducted in Europe (OR = 0.48, 95% CI 0.31-0.77), rather than in North America (OR = 0.91, 95% CI 0.67-1.24), showed the protective effect of thiopurines.

CONCLUSIONS

This meta-analysis revealed an antineoplastic effect of thiopurines on colorectal neoplasia in patients with IBD, particularly amongst patients with UC.

Tolerability profile of thiopurines in inflammatory bowel disease: a prospective experience

OBJECTIVES

The occurrence of thiopurine-related adverse events (AEs) may complicate the management of patients with inflammatory bowel disease (IBD). We aimed to evaluate the tolerability of thiopurines in a current IBD setting.

MATERIALS AND METHODS

All consecutive patients who started a treatment with azathioprine (AZA) from January 2010 to March 2016 were entered in a prospectively maintained database, and the AEs which led to the permanent discontinuation of the drug were reported.

RESULTS

Two hundred and fifty three patients were included. Median total follow-up was 32 months (range: 0.2-75 months). At the end of the study, AZA was discontinued in 160 patients (63.2%). The main reason leading to drug withdrawal was the occurrence of AEs (109/160 patients [68.1%]; cumulative incidence among the entire cohort: 43.1%). Overall, the most frequent AEs leading to treatment withdrawal were nausea (31/253 patients, 12.3%) and subjective symptoms, i.e., poorly defined side effects such as fatigue, headache and muscle pain (20/253 patients, 7.9%). Among the 109 AZA-intolerant patients, a switch to 6-mercaptopurine (6-MP) was performed in 44 cases (40.4%). At the end of follow-up, 6-MP was discontinued in 35/44 patients (79.5%), mostly due to AEs (29/35 patients, 82.8%). Azathioprine-induced hepatic and pancreatic toxicity was associated with male gender (p = .01 and p = .03, respectively), and occurrence of nausea with Crohn's disease (p = .04).

CONCLUSIONS

Our real-life prospective cohort showed the higher cumulative incidence of thiopurine withdrawal due to AEs reported to date. Switching from AZA to 6-MP was often ineffective.

Chemoprevention of colorectal cancer in ulcerative colitis: digging deep in current evidence

Patients with ulcerative colitis (UC) have an increased risk of developing colorectal cancer (CRC). Surveillance colonoscopy is currently recommended for patients with long-standing extensive colitis for reducing CRC risk. Chemoprevention is an attractive complementary strategy. Areas covered: Inflammation is a major determinant of CRC risk and is potentially modifiable. Reducing inflammation is supposed to reduce CRC risk. Several medications have been evaluated in this setting: 5-ASA, thiopurines, anti-TNFα agents and ursodeoxycholic acid (UCDA) in patients with associated primary sclerosing cholangitis (PSC). This review offers a critical evaluation of current evidence of the potential chemopreventive effect of such medications. Expert commentary: No randomized controlled trials have been performed and the available evidence come from observational studies. Although biological plausibility supports a chemopreventive role of the aforementioned agents, the overall evidence of efficacy is weak because of several methodological limitations of the studies. Indirect epidemiological evidence, biologic plausibility and results of meta-analyses reasonably support a potential chemopreventive effect of 5-ASA. Available evidence does not support a specific chemopreventive effect of purine analogues and anti-TNFα medications, despite their efficacy in the management of inflammatory bowel disease. Data addressing UDCA and folate supplementation are inconclusive. Limited data are available for statins.

Crohn's disease: risk factor for colorectal cancer

Background Crohn's disease is an inflammatory disease that can reach any part of the gastrointestinal tract. This disease has been associated with an increased neoplastic risk, including colorectal carcinoma.

Objective The objective of this work is to describe the mechanisms present in two diseases, and that are responsible for the increased risk in Crohn's disease.

Methods A bibliographic research was conducted in PubMed database. In addition to the articles obtained with an inserted query in Pubmed, other references relevant to the topic in question were included.

Results Colorectal cancer risk varies according to the presence of certain factors, and an example of this is Crohn's disease. Chronic inflammation seems to be an important contribution to carcinogenesis, since it creates a microenvironment suitable for the onset and progression of the disease. There are molecular changes that are common to two conditions, thus justifying the fact of Crohn's disease being a risk factor for colorectal carcinoma. The disease control with an appropriate therapy and with surveillance are two ways to control this risk.

Conclusions A proinflammatory state is the cornerstone in the association between Crohn's disease and colorectal carcinoma. The implementation of surveillance strategies allowed a decrease in morbidity and mortality associated with this cancer.

Chemoprevention of colorectal cancer in inflammatory bowel disease

INTRODUCTION

Patients with inflammatory bowel disease are at an increased risk of colorectal cancer when compared to the general population. Chronic inflammation is thought to be the underlying cause, and medications that reduce inflammation have the potential to reduce the risk of colorectal cancer. Areas covered: After conducting a PubMed search for relevant literature, we examined several classes of medications that have been studied as potential chemopreventive agents. These include 5-aminosalicylates, thiopurines, tumor necrosis factor antagonists, ursodeoxycholic acid, NSAIDs, and statins. Expert commentary: While each class of medications has some data to support its use in chemoprevention, the majority of the evidence in each case argues against the routine use of these medications solely for a chemopreventive benefit.

The effects of aminosalicylates or thiopurines on the risk of colorectal cancer in inflammatory bowel disease

BACKGROUND

Whether aminosalicylates or thiopurines reduce the risk of colorectal cancer (CRC) in inflammatory bowel (IBD) disease is controversial.

AIM

To assess simultaneously the chemopreventive effect of aminosalicylates or thiopurines in a case-control study nested in the CESAME observational cohort that enrolled consecutive patients with IBD between May 2004 and June 2005. Patients were followed up to December 2007.

METHODS

Study population comprised 144 case patients who developed CRC from the diagnosis of IBD (65 and 79 cases diagnosed, respectively, before and from 2004, starting year of the prospective observational period of CESAME) and 286 controls matched for gender, age, IBD subtype and year of diagnosis, and cumulative extent of colitis. Exposure to aminosalicylates or thiopurines was defined by an exposure to the treatment during the year of the diagnosis of cancer. The propensity of receiving 5-ASA and thiopurines was quantified by a composite score taking into account patient and IBD characteristics. The role of aminosalicylates or thiopurines was assessed by multivariate analysis. Propensity scores and the history of primary sclerosing cholangitis were entered into the multivariate model for adjustment.

RESULTS

By multivariate analysis adjusted for propensity, a significant protective effect of exposure to drugs during the year of cancer was found for aminosalicylates (OR = 0.587, 95% CI: 0.367-0.937, P = 0.0257), but not for thiopurines (OR = 0.762, 95% CI: 0.432-1.343, P = 0.3468).

CONCLUSION

In a case-control study nested in the CESAME cohort, a significant decrease in the risk of colorectal cancer in IBD was associated with exposure to aminosalicylates, not to thiopurines.

The problem of adherence to therapy in ulcerative colitis and the potential utility of multi-matrix system (MMX) technology

Ulcerative colitis (uc) is a chronic condition and for the vast majority of patients, life-long treatment is required. low adherence to therapy is an emerging issue. since low adherence is associated with poor clinical outcomes and increased costs, it is becoming crucial to identify strategies in order to improve it. Areas covered: We performed literature searches in PubMed using the terms 'adherence', 'mesalamine', 'budesonide MMX', 'MMX technology' in combination with 'ulcerative colitis'. Firstly, we present the key-concepts of therapy for UC and discuss the problem of the adherence and how to measure it. Then, we provide data on the extent of the problem and the causes and consequences from clinical and economic point of views. Finally, we focus on treatment-related variables associated with non-adherence and treatment-related strategies to improve adherence, paying particular attention to Multi Matrix system (MMX) technology applied to mesalazine and budesonide. Expert commentary: The pharmaceutical industry and scientific community are making efforts to simplify treatments for UC. MMX technology, which allows a reduction in the number of pills to be taken and daily administrations, may facilitate adherence to treatment and carry further clinical benefits.

Thiopurines and inflammatory bowel disease: Current evidence and a historical perspective

The use of thiopurines in inflammatory bowel disease (IBD) has been examined in numerous prospective, controlled trials, with a majority demonstrating a clinical benefit. We conducted this review to describe the historical and current evidence in the use of thiopurines in IBD. A systematic search was performed on MEDLINE between 1965 and 2016 to identify studies on thiopurines in IBD. The most robust evidence for thiopurines in IBD includes induction of remission in combination with anti-tumor necrosis factor (anti-TNF) agents, and maintenance of remission and post-operative maintenance in Crohn’s disease. Less evidence exists for thiopurine monotherapy in induction of remission, maintenance of ulcerative colitis, chemoprevention of colorectal cancer, and in preventing immunogenicity to anti-TNF. Evidence was often limited by trial design. Overall, thiopurines have demonstrated efficacy in a broad range of presentations of IBD. With more efficacious novel therapeutic agents, the positioning of thiopurines in the management of IBD will change and future studies will analyze the benefit of thiopurines alone and in conjunction with these new medications.

No Evidence That Azathioprine Increases Risk of Cholangiocarcinoma in Patients With Primary Sclerosing Cholangitis

BACKGROUND & AIMS

Patients with primary sclerosing cholangitis (PSC) are at increased risk for developing cholangiocarcinoma (CCA). Patients with PSC also can have inflammatory bowel diseases (IBDs) or features of autoimmune hepatitis (AIH), and therefore are treated with azathioprine. Azathioprine has been associated with an increased risk for malignancy, therefore we investigated whether azathioprine use affects the risk of CCA in persons with PSC.

METHODS

We performed a retrospective study of well-defined patients with PSC using data collected from 3 large-volume, tertiary care centers in Germany and Norway. We analyzed data from 638 patients (70% men; 5900 patient-years of follow-up evaluation); 91 patients had received azathioprine therapy (considered to be effective at 90 days after first intake). Risk analysis was performed using the Cox proportional hazard model when risks competing with study end points were present.

RESULTS

Of patients who received azathioprine treatment, 3.3% developed CCA, compared with 6.8% of patients without azathioprine treatment. However, azathioprine did not significantly affect the risk for CCA (hazard ratio, 0.96; 95% confidence interval, 0.29-3.13; P = .94). The only factor associated with an increased risk of CCA was age 35 years or older at PSC diagnosis (hazard ratio, 3.87; 95% confidence interval, 1.96-7.67; P < .01). Patient sex, concomitant IBD, or AIH did not affect the risk of CCA. Overall, the cumulative 10-year incidence of CCA was 4.6% and the cumulative 15-year incidence was 7.7%.

CONCLUSIONS

A retrospective analysis of patients with PSC treated at tertiary centers in Europe found no evidence that azathioprine significantly affects the risk of CCA. Azathioprine therefore should not be withheld from patients with PSC and concomitant IBD and/or AIH.

Statin Use Is Associated With Reduced Risk of Colorectal Cancer in Patients With Inflammatory Bowel Diseases

BACKGROUND & AIMS

Inflammatory bowel diseases (IBDs) such as Crohn's disease and ulcerative colitis are associated with an increased risk of colorectal cancer (CRC). Chemopreventive strategies have produced weak or inconsistent results. Statins have been associated inversely with sporadic CRC. We examined their role as chemopreventive agents in patients with IBD.

METHODS

We collected data from 11,001 patients with IBD receiving care at hospitals in the Greater Boston metropolitan area from 1998 through 2010. Diagnoses of CRC were determined using validated International Classification of Diseases, 9th revision, Clinical Modification codes. Statin use before diagnosis was assessed through analysis of electronic prescriptions. We performed multivariate logistic regression analyses, adjusting for potential confounders including primary sclerosing cholangitis, smoking, increased levels of inflammation markers, and CRC screening practices to identify an independent association between statin use and CRC. We performed sensitivity analyses using propensity score adjustment and variation in the definition of statin use.

RESULTS

In our cohort, 1376 of the patients (12.5%) received 1 or more prescriptions for a statin. Patients using statins were more likely to be older, male, white, smokers, and have greater comorbidity than nonusers. Over a follow-up period of 9 years, 2% of statin users developed CRC compared with 3% of nonusers (age-adjusted odds ratio, 0.35; 95% confidence interval, 0.24-0.53). On multivariate analysis, statin use remained independently and inversely associated with CRC (odds ratio, 0.42; 95% confidence interval, 0.28-0.62). Our findings were robust on a variety of sensitivity and subgroup analyses.

CONCLUSIONS

Statin use was associated inversely with the risk of CRC in a large IBD cohort. Prospective studies on the role of statins as chemopreventive agents are warranted.

Importance of the alternative NF-κB activation pathway in inflammation-associated gastrointestinal carcinogenesis

Chronic inflammation is a common factor in the development of many gastrointestinal malignancies. Examples include inflammatory bowel disease predisposing to colorectal cancer, Barrett's esophagus as a precursor of esophageal adenocarcinoma, and Helicobacter pylori-induced gastric cancer. The classical activation pathway of NF-κB signaling has been identified as regulating several sporadic and inflammation-associated gastrointestinal tract malignancies. Emerging evidence suggests that the alternative NF-κB signaling pathway also exerts a distinct influence on these processes. This review brings together current knowledge of the role of the alternative NF-κB signaling pathway in the gastrointestinal tract, with a particular emphasis on inflammation-associated cancer development.

Comparison of Estimates between Cohort and Case-Control Studies in Meta-Analyses of Therapeutic Interventions: A Meta-Epidemiological Study

Background

Observational studies are increasingly being used for assessing therapeutic interventions. Case–control studies are generally considered to have greater risk of bias than cohort studies, but we lack evidence of differences in effect estimates between the 2 study types. We aimed to compare estimates between cohort and case–control studies in meta-analyses of observational studies of therapeutic interventions by using a meta-epidemiological study.

Methods

We used a random sample of meta-analyses of therapeutic interventions published in 2013 that included both cohort and case–control studies assessing a binary outcome. For each meta-analysis, the ratio of estimates (RE) was calculated by comparing the estimate in case–control studies to that in cohort studies. Then, we used random-effects meta-analysis to estimate a combined RE across meta-analyses. An RE < 1 indicated that case–control studies yielded larger estimates than cohort studies.

Results

The final analysis included 23 meta-analyses: 138 cohort and 133 case–control studies. Treatment effect estimates did not significantly differ between case–control and cohort studies (combined RE 0.97 [95% CI 0.86–1.09]). Heterogeneity was low, with between–meta-analysis variance τ² = 0.0049. Estimates did not differ between case–control and prospective or retrospective cohort studies (RE = 1.05 [95% CI 0.96–1.15] and RE = 0.99 [95% CI, 0.83–1.19], respectively). Sensitivity analysis of studies reporting adjusted estimates also revealed no significant difference (RE = 1.03 [95% CI 0.91–1.16]). Heterogeneity was also low for these analyses.

Conclusion

We found no significant difference in treatment effect estimates between case–control and cohort studies assessing therapeutic interventions.

Cancer and immunomodulators in inflammatory bowel diseases

The widespread use of thiopurines and anti-tumor necrosis factors (TNFs) in inflammatory bowel disease (IBD) is a rising concern regarding their potential cancer risk. MEDLINE, EMBASE, and the Cochrane Library database were searched for articles regarding immunomodulators anti-TNF agents in IBD, hematologic malignancies, and solid tumors. Current evidences support that thiopurines and anti-TNFs used alone or in combination do not increase the overall cancer risk in IBD. Thiopurines use, with or without anti-TNFs, is associated with an increased risk of lymphoma, particularly non-Hodgkin lymphoma, in Crohn's disease. Combined treatment significantly increases the risk of a rare hepatosplenic T-cell lymphoma, particularly in young male patients with Crohn's disease. An increased risk of nonmelanotic skin cancer is also observed when using thiopurines in IBD, whereas a slightly increased risk of melanoma is observed when using anti-TNFs. The role played by immunomodulators in the development of other cancer types (i.e., urinary) as also by the severity of IBD is under investigation. Although the incidence of specific malignancies (lymphoma, skin cancers) seems to be increased by immunomodulators, their absolute number is low. As thiopurines and anti-TNFs are highly effective in IBD, current evidences support that in appropriate hands, their benefits overwhelm the cancer risk. However, a careful selection of both patients and timing of treatment is mandatory, particularly in young male patients with Crohn's disease. Immunomodulators should therefore be handled by experienced and dedicated gastroenterologists who aware of the potential, although low, cancer risk associated with their use in patients with IBD.

Malignancies in inflammatory bowel disease

Patients with inflammatory bowel diseases (IBDs) are at increased risk of colorectal cancer (CRC), but the risk varies between different studies and seems to be decreasing. The cumulative risk of CRC has been reported to be 1%, 2%, and 5% after 10, 20, and over 20 years of disease duration, respectively, in recent meta-analysis. Disease duration and grade of inflammation are the main driving forces of dysplasia and CRC development. Also, the risk of extraintestinal cancers is increased in IBD, where the degree of immunosuppression and its duration are the most important risk factors. Most important extraintestinal malignancies are lymphomas and non-melanoma skin cancers, both of which are increased in patients receiving thiopurines. Also, extraintestinal manifestations or concomitant diseases such as primary sclerosing cholangitis predispose IBD patients to malignancies such as cholangiocarcinoma. History of previous cancer increases the risk of developing either new or recurrent cancers and should be taken into account when choosing therapy and planning surveillance. Dysplasia and cancer screening and surveillance must be individualized according to patients' risk factors. Malignancies are the second most common cause of death after cardiovascular diseases in both genders in patients with IBD.

Chemoprevention of colorectal cancer

Colorectal cancer has become one of the most prevalent malignant diseases for both men and women. Patients with inflammatory bowel diseases or certain inherited cancer syndromes are at high risk of developing colorectal cancer and have naturally the highest need for cancer prevention. In familial adenomatous polyposis (FAP) and Lynch syndrome, most of the underlying germline mutations can be detected by DNA sequencing, and medical counselling of affected individuals involves both surveillance tests and chemopreventive measures. However, as the mechanisms leading to colorectal cancer differ in these high-risk groups, the molecular action of chemopreventive drugs needs to be adjusted to the certain pathway of carcinogenesis. In the last decades, a number of drugs have been tested, including sulindac, aspirin, celecoxib, and mesalazine, but some of them are still controversially discussed. This review summarizes the advances and current standards of colorectal cancer prevention in patients with inflammatory bowel disease, FAP and Lynch syndrome.

Azathioprine does not reduce adenoma formation in a mouse model of sporadic intestinal tumorigenesis

AIM: To investigate if azathioprine could reduce adenoma formation in Apc^Min/+, a mouse model of sporadic intestinal tumorigenesis.

METHODS: Azathioprine was administered via drinking water (estimated 6-20 mg/kg body weight per day) to Apc^Min/+ and wildtype mice. Control animals received vehicle only (DMSO) dissolved in drinking water. At 15 wk of age all mice were sacrificed and intestines of Apc^Min/+ were harvested for evaluation of polyp number. Azathioprine induced toxicity was investigated by immunohistochemical analysis on spleens.

RESULTS: All azathioprine treated mice showed signs of drug-associated toxicity such as weight loss and development of splenic T-cell lymphomas. Although this suggests that the thiopurine concentration was clearly in the therapeutic range, it did not reduce tumor formation (48 ± 3.1 adenomas vs 59 ± 5.7 adenomas, P = 0.148).

CONCLUSION: We conclude that in the absence of inflammation, azathioprine does not affect intestinal tumorigenesis.

The potential for medical therapy to reduce the risk of colorectal cancer and optimize surveillance in inflammatory bowel disease

It has been proposed that effective disease control through abrogation of inflammation in IBD may also reduce CRC risk in these individual patients. This article summarizes the potential for medical therapy to reduce the risk of CRC via primary and secondary prevention, and offers practical ways in which a goal of mucosal improvement or healing may be incorporated into clinical practice.

Use of thiopurines in inflammatory bowel disease: Safety issues

Thiopurines are widely used for maintenance treatment of inflammatory bowel disease. Inter-individual variability in clinical response to thiopurines may be attributed to several factors including genetic polymorphisms, severity and chronicity of disease, comorbidities, duration of administration, compliance issues and use of concomitant medication, environmental factors and clinician and patient preferences. The purpose of this review is to summarise the current evidence on thiopurine safety and toxicity, to describe adverse drug events and emphasise the significance of drug interactions, and to discuss the relative safety of thiopurine use in adults, elderly patients, children and pregnant women. Thiopurines are safe to use and well tolerated, however dose adjustment or discontinuation of treatment must be considered in cases of non-response, poor compliance or toxicity. Drug safety, clinical response to treatment and short to long term risks and benefits must be balanced throughout treatment duration for different categories of patients. Treatment should be individualised and stratified according to patient requirements. Enzymatic testing prior to treatment commencement is advised. Surveillance with regular clinic follow-up and monitoring of laboratory markers is important. Data on long term efficacy, safety of thiopurine use and interaction with other disease modifying drugs are lacking, especially in paediatric inflammatory bowel disease. High quality, collaborative clinical research is required so as to inform clinical practice in the future.

Current and emerging maintenance therapies for ulcerative colitis

Ulcerative colitis (UC) is a chronic idiopathic intestinal disease that requires life-long maintenance therapy to maintain clinical remission. This article reviews the current literature on maintenance treatments in UC. It examines the natural history of the condition and the proposed benefits of treatment. These include improving quality of life parameters, decreasing corticosteroid intake, the prevention of relapse, the prevention of colorectal cancer and the avoidance of colectomy. The immunosuppressive era appears to be reducing the need for elective colectomy in UC. The article explores the classes of drug currently used for maintenance of UC, reviews the literature around adherence issues, and summarizes emerging agents in this space.