Relation between colitis and colon cancer

Patients with inflammatory bowel disease and post-inflammatory polyps have an increased risk of colorectal neoplasia: A meta-analysis

BACKGROUND

Longstanding intestinal inflammation increases the risk of colorectal neoplasia in patients with inflammatory bowel disease (IBD). Accurately predicting the risk of colorectal neoplasia in the early stage is still challenging. Therefore, identifying visible warning markers of colorectal neoplasia in IBD patients is the focus of the current research. Post-inflammatory polyps (PIPs) are visible markers of severe inflammation under endoscopy. To date, there is controversy regarding the necessity of strengthened surveillance strategies for IBD patients with PIPs.

AIM

To determine whether IBD patients with PIPs carryan increased risk of colorectal neoplasia.

METHODS

Researchers searched the following databases up to July 31, 2021: MEDLINE (PubMed), MEDLINE (Ovid), EMBASE, Cochrane Library, China National Knowledge Infrastructure, Wan-Fang Data, China Science and Technology Journal Database and Chinese BioMedical Literature Database. Cohort and case-control studies that compared the risk of colorectal neoplasia between IBD patients with or without PIPs and published in English or Chinese were included. Methodological quality was assessed using the Risk of Bias in Nonrandomized Studies-of Interventions assessment tool. The outcomes of interest were the rates of various grades of colorectal neoplasia. The pooled risk ratio (RR) and 95% confidence interval (95%CI) were calculated using the random-effects model. Begg’s test and Egger’s test were used to calculate the publication bias. Sensitivity and subgroup analyses were performed to verify the robustness of the results. The Grading of Recommendations, Assessment, Development and Evaluation approach was used to assess the overall quality of evidence supporting the outcomes of interest.

RESULTS

Nine studies involving 5424 IBD patients (1944 with PIPs vs 3480 without PIPs) were included. The overall bias in each included study ranged from moderate to serious. Compared with nonconcurrent PIPs, patients with PIPs had a higher risk of colorectal neoplasia (RR = 1.74, 95%CI: 1.35-2.24, P < 0.001, I² = 81.4%; aHR = 1.31, 95%CI: 1.01-1.70, P = 0.04, I² = 26.2%; aOR = 2.62, 95%CI: 1.77-3.88, P < 0.001, I² = 0%), advanced colorectal neoplasia (RR = 2.07, 95%CI: 1.49-2.87, P < 0.001, I² = 77.4%; aHR = 1.63, 95%CI: 1.05-2.53, P = 0.03, I² = 10.1%) and colorectal cancer (RR = 1.93, 95%CI: 1.32-2.82, P = 0.001, I² = 83.0%). Publication bias was not observed in Begg’s test or Egger’s test. Sensitivity and subgroup analyses showed that the results are robust. The overall quality of evidence was assessed as moderate to low.

CONCLUSION

IBD patients with PIPs may have an increased incidence of colorectal neoplasia.

Therapeutic dosages of aspirin counteract the IL-6 induced pro-tumorigenic effects by slowing down the ribosome biogenesis rate

Chronic inflammation is a risk factor for the onset of cancer and the regular use of aspirin reduces the risk of cancer development. Here we showed that therapeutic dosages of aspirin counteract the pro-tumorigenic effects of the inflammatory cytokine interleukin(IL)-6 in cancer and non-cancer cell lines, and in mouse liver in vivo. We found that therapeutic dosages of aspirin prevented IL-6 from inducing the down-regulation of p53 expression and the acquisition of the epithelial mesenchymal transition (EMT) phenotypic changes in the cell lines. This was the result of a reduction in c-Myc mRNA transcription which was responsible for a down-regulation of the ribosomal protein S6 expression which, in turn, slowed down the rRNA maturation process, thus reducing the ribosome biogenesis rate. The perturbation of ribosome biogenesis hindered the Mdm2-mediated proteasomal degradation of p53, throughout the ribosomal protein-Mdm2-p53 pathway. P53 stabilization hindered the IL-6 induction of the EMT changes. The same effects were observed in livers from mice stimulated with IL-6 and treated with aspirin. It is worth noting that aspirin down-regulated ribosome biogenesis, stabilized p53 and up-regulated E-cadherin expression in unstimulated control cells also. In conclusion, these data showed that therapeutic dosages of aspirin increase the p53-mediated tumor-suppressor activity of the cells thus being in this way able to reduce the risk of cancer onset, either or not linked to chronic inflammatory processes.

Pattern of Inflammation on Surveillance Colonoscopy Does Not Predict Development of Colitis-associated Neoplasia

BACKGROUND

Identification of colonoscopic features which increase colitis-associated neoplasia risk in patients with ulcerative colitis (UC) may allow patient risk stratification. Our objective was to investigate whether colonoscopic features correlate with the risk of developing colitis-associated neoplasia in patients with UC on surveillance.

METHODS

In this retrospective case-control study, patients with UC who underwent surveillance colonoscopies from 1998 to 2011 were included. Patients with UC with neoplasia were compared with a matched control group of patients with UC without neoplasia in a 1:3 ratio.

RESULTS

A total of 111 eligible patients with UC with colon neoplasia were compared with 356 patients with UC without colon neoplasia. On univariate analysis, colitis-associated neoplasia was associated with male gender (odds ratio [OR] = 2.58, 95% confidence interval [CI]: 1.71-3.89, P ≤ 0.001) and smoking history (OR = 1.62, 95% CI: 1.1-2.39, P = 0.045) but not with colonoscopic features, including tubular colon/shortened colon, scarring, segment of severe inflammation, inflammatory polyps, colonic stricture, or macroscopically normal appearance colonoscopy. In multivariate analysis, only male gender (OR = 2.68, 95% CI: 1.77-4.08, P ≤ 0.001) was found to be associated with an increased risk, whereas the use of 5-aminosalicylates was associated with a decreased risk for colitis-associated neoplasia (OR = 0.51, 95% CI: 0.31-0.84, P = 0.009).

CONCLUSIONS

In patients with UC, colonoscopic features especially on standard-definition white-light colonoscopy did not appear to reliably predict the development of colitis-associated neoplasia. This will leave room for image-enhanced endoscopy technology and molecular markers for the early and accurate detection of colitis-associated neoplasia.

IL-32α suppresses colorectal cancer development via TNFR1-mediated death signaling

Inflammation is associated with cancer-prone microenvironment, leading to cancer. IL-32 is expressed in chronic inflammation-linked human cancers. To investigate IL-32α in inflammation-linked colorectal carcinogenesis, we generated a strain of mice, expressing IL-32 (IL-32α-Tg). In IL-32α-Tg mice, azoxymethane (AOM)-induced colon cancer incidence was decreased, whereas expression of TNFR1 and TNFR1-medicated apoptosis was increased. Also, IL-32α increased ROS production to induce prolonged JNK activation. In colon cancer patients, IL-32α and TNFR1 were increased. These findings indicate that IL-32α suppressed colon cancer development by promoting the death signaling of TNFR1.

Mucosal healing in inflammatory bowel disease

It is becoming increasingly recognized that purely clinical endpoints may not be sufficient in the treatment of patients with inflammatory bowel disease. As such, mucosal disease assessment has become a prominent component of the majority of recent clinical trials in Crohn's disease and ulcerative colitis. There is mounting evidence that the attainment of mucosal healing leads to improved clinical outcomes in both Crohn's disease and ulcerative colitis. However, the use of mucosal healing as a therapeutic endpoint in inflammatory bowel disease is in its early stages, as a number of issues limit its application to routine clinical practice.

Colorectal cancer complicating inflammatory bowel disease: a comparative study of Crohn's disease vs ulcerative colitis in 34 patients

AIM

Colorectal cancer (CRC) complicating inflammatory bowel disease (IBD) accounts for 10-15% of all IBD deaths. Survival of patients with IBD-related CRC was reviewed to analyse differences between ulcerative colitis (UC) and Crohn's disease (CD).

METHOD

We analysed (24 men and 10 women) patients with CD (n = 14) or UC (n = 20) with CRC, who presented between 1990 and 2007, and were followed to October, 2009.

RESULTS

The mean age of patients was 56 ± 12 years for patients with UC and 49 ± 17 years for patients with CD, and the mean duration of symptoms was 22 ± 11 and 16 ± 8 years, respectively. The median duration of follow up after the diagnosis of CRC was 49 (1-157) months. Recurrence occurred in five patients with UC and in nine with CD (P = 0.02). The overall and disease free five year survivals were significantly higher in patients with UC than CD [70%vs 43% (P = 0.01) and 63%vs 31% (P = 0.01), respectively].

CONCLUSION

The results showed a poorer prognosis of CRC in patients with CD than with UC.

Importance of mucosal healing in ulcerative colitis

Treatment of patients with ulcerative colitis (UC) has traditionally focused on improving symptoms, with the main objective of inducing and maintaining symptomatic remission. However, new evidence suggests that concentrating exclusively on clinical outcome measures may not be adequate to achieve long-term treatment success. Indeed, physicians should also be assessing the reduction of endoscopic activity, with the intention of achieving complete mucosal healing (defined as the absence of all mucosal ulceration, both microscopic and macroscopic, providing a sigmoidoscopy score of 0, as assessed on the Ulcerative Colitis Disease Activity Index). As a consequence of the customary reliance on symptomatic outcome measures, relatively few clinical trials have used mucosal healing or a composite including mucosal healing as a primary endpoint. This situation may soon change as new guidelines recommend the incorporation of mucosal healing into the primary endpoint of all new clinical trials in patients with UC. These recommendations are derived, in part, from data that have illustrated a correlation between mucosal healing and several important factors including long-term remission rates, disease-related complications (e.g., risk of colorectal cancer), healthcare utilization (e.g., need for colectomy), and patient quality of life. We already have drugs available to us that can effectively induce and maintain complete mucosal healing over long periods of time. This review evaluates the effect of medical therapy on mucosal healing in patients with UC and explores the importance of this outcome measure, both from the patient's perspective and clinical trial experience. Inflamm Bowel Dis 2009.

Immune effector cells produce lethal DNA damage in cells treated with a thiopurine

Azathioprine, a widely used immunosuppressant, is also used in the control of inflammatory disorders. These are characterized by the local accumulation of immune effector cells that produce reactive oxygen species (ROS). The DNA of azathioprine-treated patients contains 6-thioguanine (6-TG), a base analogue that is particularly susceptible to oxidation. Here, we show that 6-TG is vulnerable to ROS produced by chemical oxidants and that cells containing DNA 6-TG are hypersensitive to these oxidants. We also show that 6-TG incorporated into the DNA of macrophages sensitizes them to killing by endogenously produced ROS. ROS generated by macrophages are also a hazard for cocultured nonmacrophage cells containing DNA 6-TG. This bystander vulnerability of cells containing DNA 6-TG to oxidation by ROS generated by immune effector cells has implications for the long-term use of azathioprine in the management of inflammatory disorders.

Association of hyperhomocysteinemia and folate deficiency with colon tumors in patients with inflammatory bowel disease

BACKGROUND

Folate deficiency associated with hyperhomocysteinemia might increase the risk of developing colorectal cancer. The aim of this study was to evaluate factors associated with colonic carcinogenesis, in particular, folate and homocysteinemia levels, in a cross-sectional study of patients with inflammatory bowel disease (IBD).

METHODS

IBD patients with carcinogenic lesions discovered during colonoscopy [dysplasia-associated lesion or masses (DALM), colorectal cancer] were included and compared with the whole population of IBD patients with a normal colonoscopy performed during the same period. The following parameters were collected at the time of colonoscopy: age, sex, type, duration, activity, and extent of the disease, treatment, smoking status, and vitamin B12, folate, and homocysteinemia levels. Univariate and multivariate analyses were performed after adjusting for the main parameters.

RESULTS

One hundred and fourteen patients [41 with ulcerative colitis (UC), 73 with Crohn's disease (CD)] were included. Twenty-six carcinogenic lesions were isolated: 18 DALM (7 high-grade and 11 low-grade dysplasia) and 8 colorectal cancers. In univariate analysis, the factors associated with carcinogenesis were: active smoking (P = 0.03), folate level < 145 pmol/L (P = 0.02), hyperhomocysteinemia > 15 micromol/L (P = 0.003), duration of disease > 10 years (P = 0.006), and UC (P = 0.02). In multivariate analysis, patients with hyperhomocysteinemia associated with folate deficiency had 17 times as many carcinogenic lesions as patients with normal homocysteinemia whatever the folate status and duration of the disease (P = 0.01). Patients with hyperhomocysteinemia without folate deficiency had 2.5 times as many carcinogenic lesions as patients with normal homocysteinemia (P = 0.08).

CONCLUSIONS

Our data suggest that in IBD patients with normal homocysteinemia, the increase in carcinogenic risk is negligible. Conversely, in patients with hyperhomocysteinemia, folate deficiency may be associated with increased colorectal carcinogenesis in IBD patients.

Colorectal neoplasia in Crohn's colitis: a retrospective comparative study with ulcerative colitis

AIMS

To determine the clinicopathological features of colorectal cancer (CRC) in Crohn's disease (CD).

METHODS AND RESULTS

All histological slides from surgical specimens with inflammatory bowel disease-related colorectal neoplasia examined in our hospital between 1990 and 2005 were reviewed. We identified 18 CRCs in 16 patients with CD and compared them with 57 CRCs in 41 patients with ulcerative colitis (UC). We also studied 25 patients with dysplasia without cancer (CD 2, UC 23). When CD and UC were compared, the median age at diagnosis of cancer (CD 52 years, UC 51 years), the frequency of mucinous adenocarcinoma (CD 16.7%, UC 17.5%) and the frequency of dysplasia adjacent to and distal from cancer (CD 56.3 and 37.5%, UC 65.8 and 39%, respectively) were similar. All neoplastic lesions occurred in areas affected by inflammatory bowel disease.

CONCLUSIONS

CRC complicating CD and UC shares many clinicopathological features, in particular similar frequencies of dysplasia, both adjacent and distal, with cancer. Thus, surveillance for patients with Crohn's colitis should be similar to that for patients with UC. Consideration should be given to a more extensive UC-like surgical approach instead of segmental resection of the involved area.

Growth factors in inflammatory bowel disease: the actions and interactions of growth hormone and insulin-like growth factor-I

Multiple growth hormones (GHs) and factors are relevant to inflammatory bowel disease (IBD) due to their trophic effects on epithelial cells to promote mucosal integrity, renewal, and repair, on mesenchymal cells to promote wound healing, and on intestinal immune cells to modulate inflammation. The anabolic effects of GHs and factors outside the intestine are relevant to minimizing nutritional insufficiency, catabolic state, and the inability to maintain body weight due to inflammation-induced malabsorption. GHs and factors can, however, have a dual role, whereby trophic effects can be beneficial but, if excessive, can promote complications including the increased risk of intestinal tumors/adenocarcinoma and fibrosis. This review focuses on GH and insulin-like growth factor (IGF-I), for which evidence suggests such a dual role may exist. The actions of GH and IGF-I on the healthy intestine are compared with effects during intestinal inflammation or associated complications. Interactions between these growth factors and others relevant to IBD are considered. The role of the newly discovered suppressors of cytokine signaling proteins, which may dictate the balance between beneficial and excessive actions of GH and IGF-I, is also addressed.

Severity of inflammation is a risk factor for colorectal neoplasia in ulcerative colitis

BACKGROUND & AIMS

Patients with ulcerative colitis are at increased risk of colorectal cancer. It is widely believed that this is secondary to colonic inflammation. However, the severity of colonic inflammation has never been shown to be a risk factor.

METHODS

We devised a case-control study of patients with long-standing extensive ulcerative colitis to examine various potential risk factors for neoplasia. All cases of colorectal neoplasia detected from our surveillance program between January 1, 1988, and January 1, 2002, were studied (n = 68). Each patient was matched with 2 control patients from the same surveillance population (n = 136). Matching was for sex, colitis extent, age at onset, duration of colitis, and year of index surveillance colonoscopy. Segmental colonoscopic and histological inflammation was recorded by using a simple score (0, normal; 1, quiescent/chronic inflammation; and 2, 3, and 4, mild, moderate, and severe active inflammation, respectively). Other data collected included history of primary sclerosing cholangitis, family history of colorectal cancer, and smoking and drug history (mesalamine 5-aminosalicylic acid, azathioprine, and folate).

RESULTS

Univariate analysis showed a highly significant correlation between the colonoscopic (odds ratio, 2.5; P = 0.001) and histological (odds ratio, 5.1; P < 0.001) inflammation scores and the risk of colorectal neoplasia. No other factors reached statistical significance. On multivariate analysis, only the histological inflammation score remained significant (odds ratio, 4.7; P < 0.001).

CONCLUSIONS

In long-standing extensive ulcerative colitis, the severity of colonic inflammation is an important determinant of the risk of colorectal neoplasia. Endoscopic and histological grading of inflammation could allow better risk stratification for surveillance programs.

Review article: colitis-associated cancer -- time for new strategies

Colorectal cancer (CRC) remains a feared and potentially life-threatening complication of both ulcerative colitis and Crohn's colitis. Currently, the main preventive strategy is a secondary one, i.e. surveillance colonoscopy usually after 8 years of disease duration, when the risk for neoplasia begins to increase. Despite its widespread acceptance, dysplasia and cancer surveillance is unproven in terms of reducing mortality or morbidity and there is a remarkable lack of uniformity in the manner in which it is practised. In this review article, the pitfalls of dysplasia surveillance are summarized and the need for novel chemopreventive and perhaps pharmabiotic approaches for prevention are highlighted.

Gene-environment interaction and aetiology of cancer: what does it mean and how can we measure it?

One form of defence against cancer development involves a series of genes whose role is to metabolize and excrete potentially toxic compounds and to repair subtle mistakes in DNA. Much laboratory and epidemiological research over the past decade has concentrated on the identification of these genes and an assessment of their role in cancer aetiology. Of particular interest has been whether the risk of cancer associated with a particular environmental exposure differs with respect to functionally different polymorphisms of these genes, i.e. gene-environment interaction. A large number of studies have been conducted for numerous genes and also for all common cancer sites, although results have been very inconsistent and therefore inconclusive. This is partially due to the inadequate sample size of most studies to detect modest effects and the over-reporting of positive associations identified in subgroups of the dataset. There is also much confusion about the meaning of "gene-environment interaction", what type of studies should be conducted to study it and also how it should be measured. Furthermore, the very purpose of these studies is not clear; are they attempting to identify high-risk individuals, or are they simply trying to further understand the cancer process? This review will explore these questions and provide some recommendations to help ensure that the next phase of gene-environment interaction studies, which are likely to be much larger and based on many more genes, also provide some clearer answers.