Declining risk of colorectal cancer in inflammatory bowel disease: an updated meta-analysis of population-based cohort studies

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

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

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

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

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

Development and validation of risk prediction algorithms to estimate future risk of common cancers in men and women: prospective cohort study

OBJECTIVE

To derive and validate a set of clinical risk prediction algorithm to estimate the 10-year risk of 11 common cancers.

DESIGN

Prospective open cohort study using routinely collected data from 753 QResearch general practices in England. We used 565 practices to develop the scores and 188 for validation.

SUBJECTS

4.96 million patients aged 25-84 years in the derivation cohort; 1.64 million in the validation cohort. Patients were free of the relevant cancer at baseline.

METHODS

Cox proportional hazards models in the derivation cohort to derive 10-year risk algorithms. Risk factors considered included age, ethnicity, deprivation, body mass index, smoking, alcohol, previous cancer diagnoses, family history of cancer, relevant comorbidities and medication. Measures of calibration and discrimination in the validation cohort.

OUTCOMES

Incident cases of blood, breast, bowel, gastro-oesophageal, lung, oral, ovarian, pancreas, prostate, renal tract and uterine cancers. Cancers were recorded on any one of four linked data sources (general practitioner (GP), mortality, hospital or cancer records).

RESULTS

We identified 228,241 incident cases during follow-up of the 11 types of cancer. Of these 25,444 were blood; 41,315 breast; 32,626 bowel, 12,808 gastro-oesophageal; 32,187 lung; 4811 oral; 6635 ovarian; 7119 pancreatic; 35,256 prostate; 23,091 renal tract; 6949 uterine cancers. The lung cancer algorithm had the best performance with an R(2) of 64.2%; D statistic of 2.74; receiver operating characteristic curve statistic of 0.91 in women. The sensitivity for the top 10% of women at highest risk of lung cancer was 67%. Performance of the algorithms in men was very similar to that for women.

CONCLUSIONS

We have developed and validated a prediction models to quantify absolute risk of 11 common cancers. They can be used to identify patients at high risk of cancers for prevention or further assessment. The algorithms could be integrated into clinical computer systems and used to identify high-risk patients.

WEB CALCULATOR

There is a simple web calculator to implement the Qcancer 10 year risk algorithm together with the open source software for download (available at http://qcancer.org/10yr/).

The risk of colorectal cancer in patients with ulcerative colitis

BACKGROUND AND AIM

Ulcerative colitis increases the risk of developing dysplasia and colitis-associated cancer (CAC). The purpose of this study was to determine the risk factors as well as protective measures for disease burden, need for colectomy and the development of CAC in ulcerative colitis (UC) patients.

METHODS

A cohort of n = 434 UC patients was evaluated. Data analysis was performed by univariate and multivariate logistic regression. Odds ratios (OR) and 95 % confidence intervals (CI) were calculated, and significance was assessed by the likelihood ratio test.

RESULTS

Mean patient age at UC diagnosis was 45.7 ± 15.1 years which manifested mainly as pancolitis (47 %) or left-sided colitis (45.2 %). CAC was detected in ten patients (2.3 %). UC disease duration was strongly associated with the risk of CAC (P < 0.0014); disease duration between 9 and 15 years: OR of 2.5 (95 % CI 0.2-41.1), more than 15 years: OR of 21.4 (95 % CI 2.6-173.6). The risk of developing dysplasia (low-grade intraepithelial neoplasia, LGIEN and high-grade intraepithelial neoplasia, HGIEN) or the need to undergo colectomy was also significantly related to disease duration (P = 0.006, P = 0.002, respectively). Established anti-inflammatory medication (e.g., 5-ASA, anti-TNF-α) significantly reduced the risk of both dysplasia and CAC (P = 0.02).

CONCLUSIONS

Despite the use of modern therapies for UC, CAC rates remain high. In our study, risk factors included disease duration while anti-inflammatory therapies reduced the risk. Effective control of the intestinal inflammation also reduced the disease burden as indicated by decreased risk of requiring colectomy, underscoring the need for sufficient surveillance and anti-inflammatory therapies.

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

OBJECTIVE

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Does a personal or family history of malignancy preclude the use of immunomodulators and biologics in IBD

The medical treatment for inflammatory bowel disease (IBD) has improved over the past 20 years. Although the routine use of immunomodulators and biologic agents in the treatment of IBD in the modern era has been a great achievement, these medicines are associated with rare but serious adverse events. In addition to the infectious complications, there are data to suggest that some of these agents are associated with higher rates of malignancy. In a patient with a history of cancer, or a family history of cancer, the gastroenterologist must be prepared to answer questions about the oncogenic potential of these agents. Thiopurines have been associated with a small increased risk of lymphoma in patients with IBD. In addition, an association with skin cancer has been established. Methotrexate is generally considered safe in patients with a history of cancer. There may be a small risk of lymphoma and possibly skin cancer with anti-tumor necrosis factor agents, but determining the cancer risk of these medications is difficult as they are often used in combination with thiopurines. In general, a family history of cancer should not influence a patient's medical regimen. Treatment for a patient with a personal history of cancer must be individualized and take into account the type and stage of cancer, time since completion of therapy, and the opinion of an oncologist.

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.

Colorectal cancer in patients with inflammatory bowel disease: the true impact of the risk

Patients with long-standing inflammatory bowel disease (IBD) have an increased risk of colorectal cancer (CRC). The association between IBD and CRC is well supported, but reported risk estimates vary widely. Although recent evidence from population-based studies reports a decline in risk, CRC accounts for 10-15% of all deaths in IBD. The potential causes of recent epidemiological trends and the real magnitude of risk of CRC in IBD are subjects of debate. The molecular pathway leading to CRC differs from the classic adenoma-to-CRC sequence. Chronic inflammation contributes to the development of low- and high-grade dysplasia which may further convert into CRC. Patients with a young age at onset, long-standing and extensive colitis with severe inflammatory burden, a family history of sporadic CRC, and concomitant primary sclerosing cholangitis are at greatest risk. The CRC risk in patients with colonic Crohn's disease is similar to that of ulcerative colitis. IBD-associated CRC can frequently be detected at late stages and at a younger age. The long-term prognosis of CRC may be poorer in patients with IBD than in those with sporadic CRC. Regular surveillance colonoscopies may permit earlier detection of CRC, with a corresponding improved prognosis. The interval between surveillance colonoscopies is dependent on each patient's personal risk profile.

A risk-profiling approach for surveillance of inflammatory bowel disease-colorectal carcinoma is more cost-effective: a comparative cost-effectiveness analysis between international guidelines

BACKGROUND

Colonoscopic surveillance for neoplasia is recommended for patients with inflammatory bowel disease (IBD)-related colitis. However, data on cost-effectiveness predate current international guidelines.

OBJECTIVE

To compare cost-effectiveness based on contemporary data between the surveillance strategies of the American Gastroenterological Association (AGA) and British Society of Gastroenterology (BSG).

DESIGN

We constructed a Markov decision model to simulate the clinical course of IBD patients.

SETTING

We compared the 2 surveillance strategies for a base case of a 40-year-old colitis patient who was followed for 40 years.

PATIENTS

AGA surveillance distinguishes 2 groups: a high-risk group with annual surveillance and an average-risk group with biannual surveillance. BSG surveillance distinguishes 3 risk groups with yearly, 3-year, or 5-year surveillance.

INTERVENTIONS

Patients could move from a no-dysplasia state with colonoscopic surveillance to 1 of 3 states for which proctocolectomy was indicated: (1) dysplasia/local cancer, (2) regional/metastasized cancer, or (3) refractory disease. After proctocolectomy, a patient moved to a no-colon state without surveillance.

MAIN OUTCOME MEASUREMENTS

Direct costs of medical care, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios.

RESULTS

BSG surveillance dominated AGA surveillance with $9846 per QALY. Both strategies were equally effective with 24.16 QALYs, but BSG surveillance was associated with lower costs because of fewer colonoscopies performed. Costs related to IBD, surgery, or cancer did not affect cost-effectiveness.

LIMITATIONS

The model depends on the accuracy of derived data, and the assumptions that were made to reflect real-life situations. Study conclusions may only apply to the U.S. health care system.

CONCLUSION

The updated risk-profiling approach for surveillance of IBD colorectal carcinoma by the BSG guideline appears to be more cost-effective.

Chromoendoscopy for colorectal cancer surveillance in patients with inflammatory bowel disease

Chromoendoscopy utilizes colorimetric techniques to increase detection of lesions that are difficult to see or cannot be seen with conventional white light endoscopy. Multiple studies have demonstrated that chromoendoscopy with dye spraying significantly increases the detection of dysplastic lesions in patients with chronic inflammatory bowel disease (IBD) of the colon undergoing colonoscopy. Furthermore, chromoendoscopy may obviate the need for random biopsies and pending additional studies and may allow increased intervals between surveillance exams, reducing costs while increasing the sensitivity for detection of dysplasia per exam. Despite convincing data supporting the use of chromoendoscopy for IBD colonic surveillance, it is seldom utilized outside of academic centers. Here, we review the current approach to colorectal cancer surveillance in IBD focusing on the data supporting the use of chromoendoscopy including its use in a community setting and offer practical recommendations for incorporating chromoendoscopy as a routine part of surveillance in IBD regardless of practice setting.

A clinical perspective on the role of chronic inflammation in gastrointestinal cancer

Chronic inflammation has been identified as an important risk factor for the development of malignancy, and knowledge about its molecular and cellular mechanisms is increasing. Several chronic inflammatory diseases of the gastrointestinal tract are important as risk factors for malignancy and have been studied in detail. In this review, we summarize important molecular mechanisms in chronic inflammation and highlight established and potential links between chronic inflammation and gastrointestinal cancer. In addition, we present the role of chronic inflammation in numerous tumors within the gastrointestinal tract as well as the relevant pathways or epidemiologic observations linking the pathogenesis of these tumors to inflammation.

Novel diagnostic and therapeutic techniques for surveillance of dysplasia in patients with inflammatory bowel disease

The risk for developing dysplasia and colorectal cancer in patients with longstanding inflammatory bowel disease (IBD) involving the colon is well documented. Random biopsies during white-light, standard-definition colonoscopy (33 to 50 biopsies) with or without dye spraying chromoendoscopy has been the recommended strategy in North America to detect dysplastic lesions in IBD. However, there are several limitations to this approach including poor physician adherence, poor sensitivity, increased procedure time and considerable cost. The new generation of high-definition endoscopes with electronic filter technology provide an opportunity to visualize colonic mucosal and vascular patterns in minute detail, and to identify subtle flat, multifocal, polypoid and pseudopolypoid neoplastic and non-neoplastic lesions. The application of these new technologies in IBD is slowly being adopted in clinical practice. In addition, the advent of confocal laser endomicroscopy provides an opportunity to explore real-time histology, thus redefining the understanding and characterization of the lesions in IBD. There is emerging evidence that serrated adenomas are also associated with longstanding IBD colitis and may be recognized as another important contributing factor to colorectal cancer development. The circumscribed neoplastic lesions can be treated using endoscopic therapeutic management such as mucosal resection or, especially, endoscopic submucosal dissection. This may replace panproctocolectomy in selected patients. The authors review the potential of these techniques to transform endoscopic diagnosis and therapeutic management of dysplasia in IBD.

Fecal calprotectin testing can identify ineffective colorectal cancer surveillance procedures in patients with longstanding colitis

BACKGROUND

Active colitis impairs neoplasia detection during colonoscopic surveillance for colorectal cancer in patients with inflammatory bowel disease. We investigated whether fecal calprotectin testing before surveillance colonoscopy might identify ineffective surveillance procedures.

METHODS

All consecutive patients with Crohn's disease or ulcerative colitis scheduled for surveillance colonoscopy were asked to collect a stool sample before the start of bowel cleansing. Ineffective surveillance was defined as at least 1 colonic segment with moderate or severe inflammation. Calprotectin was analyzed using an enzyme-linked immunosorbent assay (Ridascreen; R-Biopharm). Receiver operator characteristics statistics were used to determine the optimal cutoff for calprotectin.

RESULTS

A total of 176 surveillance colonoscopies were performed in 164 patients, of which 83 had Crohn's disease and 81 had ulcerative colitis or inflammatory bowel disease-unclassified. Complete endoscopic remission or mild inflammation categorized as effective surveillance was observed in 151 colonoscopies (86%), whereas moderate or severe inflammation categorized as ineffective surveillance was observed in 25 colonoscopies (14%). Median calprotectin levels for the effective and ineffective surveillance group were 84 mg/kg (range, 20-4609) and 1605 mg/kg (range, 66-26,336), respectively (P < 0.01). A cutoff of 539 mg/kg identified patients with ineffective surveillance with 84% sensitivity, 89% specificity, 55% positive predictive value, 97% negative predictive value, and an area under the curve of 0.89.

CONCLUSIONS

Low fecal calprotectin accurately identifies inflammatory bowel disease patients without colonic inflammation in whom colorectal cancer surveillance is most effective.

Current approaches to the management of new-onset ulcerative colitis

Ulcerative colitis (UC) is an idiopathic, inflammatory gastrointestinal disease of the colon. As a chronic condition, UC follows a relapsing and remitting course with medical maintenance during periods of quiescent disease and appropriate escalation of therapy during times of flare. Initial treatment strategies must not only take into account current clinical presentation (with specific regard for extent and severity of disease activity) but must also take into consideration treatment options for the long-term. The following review offers an approach to new-onset UC with a focus on early treatment strategies. An introduction to the disease entity is provided along with an approach to initial diagnosis. Stratification of patients based on clinical parameters, disease extent, and severity of illness is paramount to determining course of therapy. Frequent assessments are required to determine clinical response, and treatment intensification may be warranted if expected improvement goals are not appropriately reached. Mild-to- moderate UC can be managed with aminosalicylates, mesalamine, and topical corticosteroids with oral corticosteroids reserved for unresponsive cases. Moderate-to-severe UC generally requires oral or intravenous corticosteroids in the short-term with consideration of long-term management options such as biologic agents (as initial therapy or in transition from steroids) or thiopurines (as bridging therapy). Patients with severe or fulminant UC who are recalcitrant to medical therapy or who develop disease complications (such as toxic megacolon) should be considered for colectomy. Early surgical referral in severe or refractory UC is crucial, and colectomy may be a life-saving procedure. The authors provide a comprehensive evidence-based approach to current treatment options for new-onset UC with discussion of long-term therapeutic efficacy and safety, patient-centered perspectives including quality of life and medication compliance, and future directions in related inflammatory bowel disease care.

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.

Insight into mucinous colorectal carcinoma: clues from etiology

The prognostic impact of mucinous carcinoma (MC) in colorectal cancer (CRC) has been subject to debate ever since the introduction of the classification of tumors according to their histological differentiation. MC is a distinct clinical and pathological entity within the spectrum of CRC and accounts for approximately 10-15 % of cases. Factors involved in MC development have not been completely understood, but clinical observations may lead to a better insight into the etiology of MC. In this article, we provide an in-depth review of the literature regarding etiological aspects of MC. We show that there are worldwide differences in the prevalence of MC, with low rates in Asian countries and higher rates in the western world. Moreover, MC is more commonly diagnosed in patients suffering from inflammatory bowel diseases or Lynch syndrome and an increased rate of MC is observed in patients with radiotherapy-induced CRCs. These findings are suggestive of a different oncogenic development. Identification of conditions that are associated with MC generates insight into the etiological pathways leading to the development of this special subtype.

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

BACKGROUND

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

OBJECTIVE

Inflammatory bowel disease (IBD) is commonly treated with thiopurines such as azathioprine and mercaptopurine for the maintenance of remission. Studies examining chemopreventive of these medications on colorectal neoplasm in IBD patients have yielded conflicting results. We performed a meta-analysis to assess the role of thiopurines for this indication.

METHODS

We performed a systematic search of PubMed, Web of Science, EMBASE and Cochrane to identify studies reporting colorectal neoplasm from IBD patients treated with thiopurines and conducted a meta-analysis of pooled relative risk (RR) using the random effects model.

RESULTS

Nine case-control and ten cohort studies fulfilled the inclusion criteria. The use of thiopurines was associated with a statistically significant decreased incidence of colorectal neoplasm (summary RR=0.71, 95% CI=0.54-0.94, p=0.017), even after adjustment for duration and extent of the disease, but there was high heterogeneity among studies (I(2)=68.0%, p<0.001). The RR of advanced neoplasm (high-grade dysplasia and cancer) was 0.72 (95%CI=0.50-1.03, p=0.070) and that of cancer was 0.70 (95% CI=0.46-1.09, p=0.111) for thiopurine-treated patients. Heterogeneity of the studies was affected by the sample size (

CONCLUSION

The current meta-analysis revealed that thiopurines had a chemopreventive effect of colorectal neoplasms and a tendency of reducing advanced colorectal neoplasms in IBD. Due to the heterogeneity of included studies, these results should be interpreted with caution.

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Key Words Collapse

MESH Headings

• Azathioprine/adverse effects
• Azathioprine/therapeutic use
• Colorectal Neoplasms/chemically induced
• Humans
• Inflammatory Bowel Diseases/drug therapy
• Mercaptopurine/adverse effects
• Mercaptopurine/therapeutic use
• Risk

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Affiliation(s)

Jianfeng Gong Department of General Surgery, Jinling hospital, Medical School of Nanjing University, Nanjing, PR China
Lijing Zhu Department of Oncology, Drum Tower hospital, Medical school of Nanjing University, Nanjing, PR China
Zhen Guo Department of General Surgery, Jinling hospital, Medical School of Nanjing University, Nanjing, PR China
Yi Li Department of General Surgery, Jinling hospital, Medical School of Nanjing University, Nanjing, PR China
Weiming Zhu Department of General Surgery, Jinling hospital, Medical School of Nanjing University, Nanjing, PR China
Ning Li Department of General Surgery, Jinling hospital, Medical School of Nanjing University, Nanjing, PR China
Jieshou Li Department of General Surgery, Jinling hospital, Medical School of Nanjing University, Nanjing, PR China

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Has the risk of colorectal cancer in inflammatory bowel disease decreased?

The association between inflammatory bowel disease (IBD) and colorectal cancer (CRC) has been acknowledged for almost a century and is assumedly promoted by a chronic inflammation-driven carcinogenic process in the intestine in combination with a genetic predisposition. The magnitude of the risk of CRC in IBD remains a continuing subject of debate. The early, high risk estimates for CRC in IBD were most likely overestimated due to selected patient populations originating from tertiary referral centers with a disproportional high percentage of patients with severe disease. Later population-based studies calculating risk estimates from a broad spectrum of IBD patients have found the risk to be significantly lower. At present, there is evidence that IBD patients with longstanding and extensive disease with uncontrolled inflammation are those at increased risk. Additional, other recognized risk factors include early age at onset, family history of CRC, and concomitant primary sclerosing cholangitis. A significant amount of effort is put into identifying potential preventive factors of CRC in IBD, including surveillance programs and chemopreventive agents but the individual effect of these remains uncertain. Interestingly, recent studies have reported a decline in risk of CRC over time. Surveillance programs and the new treatment strategies, particular biological treatment might be part of the reason for the observed decline in risk of CRC in IBD over time but future studies will have investigate this assumption.

Clonal expansions and short telomeres are associated with neoplasia in early-onset, but not late-onset, ulcerative colitis

BACKGROUND

Patients with ulcerative colitis (UC) are at risk of developing colorectal cancer. We have previously reported that cancer progression is associated with the presence of clonal expansions and shorter telomeres in nondysplastic mucosa. We sought to validate these findings in an independent case-control study.

METHODS

This study included 33 patients with UC: 14 progressors (patients with high-grade dysplasia or cancer) and 19 nonprogressors. For each patient, a mean of 5 nondysplastic biopsies from proximal, mid, and distal colon were assessed for clonal expansions, as determined by clonal length altering mutations in polyguanine tracts, and telomere length, as measured by quantitative PCR. Both parameters were compared with individual clinicopathological characteristics.

RESULTS

Clonal expansions and shorter telomeres were more frequent in nondysplastic biopsies from UC progressors than nonprogressors, but only for patients with early-onset of UC (diagnosis at younger than 50 years of age). Late-onset progressor patients had very few or no clonal expansions and longer telomeres. A few nonprogressors exhibited clonal expansions, which were associated with older age and shorter telomeres. In progressors, clonal expansions were associated with proximity to dysplasia. The mean percentage of clonally expanded mutations distinguished early-onset progressors from nonprogressors with 100% sensitivity and 80% specificity.

CONCLUSIONS

Early-onset progressors develop cancer in a field of clonally expanded epithelium with shorter telomeres. The detection of these clones in a few random nondysplastic colon biopsies is a promising cancer biomarker in early-onset UC. Curiously, patients with late-onset UC seem to develop cancer without the involvement of such fields.