The colorectal adenoma-carcinoma sequence

Stage migration of testicular germ cell tumours in Alberta, Canada, during the COVID-19 pandemic: a retrospective cohort study

BACKGROUND

An absence of screening recommendations and the rapid progression of testicular germ cell tumours (TGCTs) offer a perspective on the potential impact of the COVID-19 pandemic on cancer presentations. We evaluated the presenting cancer stages of TGCTs in a real-world population before and during the pandemic to assess stage migration.

METHODS

We performed a retrospective review of all new patients with TGCT diagnoses in Alberta, Canada, from Dec. 31, 2018, to Apr. 30, 2021, using the Alberta Cancer Registry. Because potential changes in staging should not occur instantaneously, we used a 6-month lag time from Apr. 1, 2020, for seminomas, and a 3-month lag time for nonseminomas, to compare initial cancer stages at presentation before and during the pandemic. We evaluated monthly rates of presentation by stage and histology. Exploratory outcomes included the largest tumour dimension, tumour markers and, for advanced disease, risk category and treatment setting.

RESULTS

Of 335 patients with TGCTs, 231 were diagnosed before the pandemic and 104 during the pandemic (using a lag time). In total, 18 (7.8%) patients diagnosed before the pandemic presented with stage III disease, compared to 16 (15.4%) diagnosed during the pandemic (relative risk 1.97, 95% confidence interval [CI] 1.05-3.72). We observed no significant differences for secondary outcomes. Without a lag time, the rate ratio for a stage II presentation decreased significantly during the pandemic (0.40, 95% CI 0.21-0.72).

INTERPRETATION

We observed signs of TGCT stage migration during the COVID-19 pandemic, driven by a decline in stage II disease and a potential rise in stage III disease. Management of TGCTs should remain a priority, even during a global pandemic.

Artificial intelligence in endoscopy: More than what meets the eye in screening colonoscopy and endosonographic evaluation of pancreatic lesions

Artificial intelligence (AI)-based tools have ushered in a new era of innovation in the field of gastrointestinal (GI) endoscopy. Despite vast improvements in endoscopic techniques and equipment, diagnostic endoscopy remains heavily operator-dependent, in particular, colonoscopy and endoscopic ultrasound (EUS). Recent reports have shown that as much as 25% of colonic adenomas may be missed at colonoscopy. This can result in an increased incidence of interval colon cancer. Similarly, EUS has been shown to have high inter-observer variability, overlap in diagnoses with a relatively low specificity for pancreatic lesions. Our understanding of Machine-learning (ML) techniques in AI have evolved over the last decade and its application in AI–based tools for endoscopic detection and diagnosis is being actively investigated at several centers. ML is an aspect of AI that is based on neural networks, and is widely used for image classification, object detection, and semantic segmentation which are key functional aspects of AI-related computer aided diagnostic systems. In this review, current status and limitations of ML, specifically for adenoma detection and endosonographic diagnosis of pancreatic lesions, will be summarized from existing literature. This will help to better understand its role as viewed through the prism of real world application in the field of GI endoscopy.

Coupé VM. A progressive three-state model to estimate time to cancer: a likelihood-based approach

BACKGROUND

To optimize colorectal cancer (CRC) screening and surveillance, information regarding the time-dependent risk of advanced adenomas (AA) to develop into CRC is crucial. However, since AA are removed after diagnosis, the time from AA to CRC cannot be observed in an ethically acceptable manner. We propose a statistical method to indirectly infer this time in a progressive three-state disease model using surveillance data.

METHODS

Sixteen models were specified, with and without covariates. Parameters of the parametric time-to-event distributions from the adenoma-free state (AF) to AA and from AA to CRC were estimated simultaneously, by maximizing the likelihood function. Model performance was assessed via simulation. The methodology was applied to a random sample of 878 individuals from a Norwegian adenoma cohort.

RESULTS

Estimates of the parameters of the time distributions are consistent and the 95% confidence intervals (CIs) have good coverage. For the Norwegian sample (AF: 78%, AA: 20%, CRC: 2%), a Weibull model for both transition times was selected as the final model based on information criteria. The mean time among those who have made the transition to CRC since AA onset within 50 years was estimated to be 4.80 years (95% CI: 0; 7.61). The 5-year and 10-year cumulative incidence of CRC from AA was 13.8% (95% CI: 7.8%;23.8%) and 15.4% (95% CI: 8.2%;34.0%), respectively.

CONCLUSIONS

The time-dependent risk from AA to CRC is crucial to explain differences in the outcomes of microsimulation models used for the optimization of CRC prevention. Our method allows for improving models by the inclusion of data-driven time distributions.

Examining the Factors That Affect the Diagnosis of Patients with Positive Fecal Occult Blood Test Results

Due to the threat of colorectal cancer (CRC) to health, Taiwan included the fecal occult blood test (FOBT) under preventive health services in 2010. We examined the factors that affect the diagnosis of people with positive FOBT results. Data were retrospectively collected from the CRC screening database. In the model predicting factors that affect the diagnosis of 89,046 people with positive FOBT results, the risks of disease in the CRC group were lower in medical institutions that conducted follow-up examinations in regions such as Northern Taiwan compared to that in Eastern Taiwan (p = 0.013); they were lower in the age group of 50 to 65 years than those in the age group of 71 to 75 years (p < 0.001, p = 0.016), and lower in the outpatient medical units that conducted follow-up examinations than those in the inpatient medical units by 0.565 times (p < 0.001, 95% CI: 0.493−0.647). Factors affecting the diagnosis of patients with positive FOBT results were gender, the region of the medical institution, medical unit for follow-up examinations, age, screening site, family history, type of follow-up examinations, and follow-up time. Therefore, the identification of characteristics of patients with positive FOBT results and the promotion of follow-up examination are important prevention strategies for CRC.

Serum Chloride and Admission Status Are Potential Prognostic Markers of High-Risk Polyps: A Prospective Characterization of Colorectal Polyps in a Tertiary Hospital in Saudi Arabia

Background: Colorectal cancer (CRC) is the most common cancer in men in Saudi Arabia. Other than age and family history, clinical and laboratory prognostic surrogates that may aid in streamlining and prioritization of screening colonoscopies are scarce. Through the examination of the local prevalence of advanced and malignant colorectal polyps, we hypothesized that the presence of certain clinical or laboratory parameters may signify an association with having high-risk polyps.

Methods: A prospective study over a period of one year starting on January 21, 2018 and involving all adult patients undergoing colonoscopy at King Saud Medical City, Riyadh. Of the total 1,104 recruited patients, 717 were included. The patients were sub-grouped based on the presence or absence of polyps. Patients with polyps were further sub-grouped into high-risk or low-risk polyps. Comparisons between groups were performed using univariate, relative risks (RRs), and multivariate analyses.

Results: Our polyp detection rate was 34.7% and our adenoma detection rate was 21.3%. The prevalence of advanced adenoma was 15.2% and the prevalence of malignant polyps was 6.7%. Several prognostic markers were associated with high-risk polyps such as advanced age (RR = 1.35, 95% confidence interval [CI]: 1.03 to 1.78), male gender (RR = 1.18, 95% CI: 1.06 to 1.31), inpatient status (RR = 1.46, 95% CI: 1.04 to 2.21), and low serum chloride (RR = 1.89, 95% CI: 1.05 to 2.37). With multivariate analysis, the hazard ratios for inpatient status and hypochloremia were 1.67 (95% CI: 1.034 to 2.612) and 1.12 (95% CI: 1.011 to 1.265), respectively.

Conclusion: We report the prevalence of malignant colorectal polyps in Saudi Arabia which was not reported before. Two unique prognostic markers for high-risk polyps were identified, namely, inpatient status and hypochloremia.

Does computer-aided diagnostic endoscopy improve the detection of commonly missed polyps? A meta-analysis

Background/Aims

Colonoscopy is the gold standard diagnostic method for colorectal neoplasia, allowing detection and resection of adenomatous polyps; however, significant proportions of adenomas are missed. Computer-aided detection (CADe) systems in endoscopy are currently available to help identify lesions. Diminutive (≤5 mm) and nonpedunculated polyps are most commonly missed. This meta-analysis aimed to assess whether CADe systems can improve the real-time detection of these commonly missed lesions.

Methods

A comprehensive literature search was performed. Randomized controlled trials evaluating CADe systems categorized by morphology and lesion size were included. The mean number of polyps and adenomas per patient was derived. Independent proportions and their differences were calculated using DerSimonian and Laird random-effects modeling.

Results

Seven studies, including 2,595 CADe-assisted colonoscopies and 2,622 conventional colonoscopies, were analyzed. CADe-assisted colonoscopy demonstrated an 80% increase in the mean number of diminutive adenomas detected per patient compared with conventional colonoscopy (0.31 vs. 0.17; effect size, 0.13; 95% confidence interval [CI], 0.09–0.18); it also demonstrated a 91.7% increase in the mean number of nonpedunculated adenomas detected per patient (0.32 vs. 0.19; effect size, 0.05; 95% CI, 0.02–0.07).

Conclusions

CADe-assisted endoscopy significantly improved the detection of most commonly missed adenomas. Although this method is a potentially exciting technology, limitations still apply to current data, prompting the need for further real-time studies.

Comparative Study of the Role of Interepithelial Mucosal Mast Cells in the Context of Intestinal Adenoma-Carcinoma Progression

Mast cells (MCs) are crucial players in the relationship between the tumor microenvironment (TME) and cancer cells and have been shown to influence angiogenesis and progression of human colorectal cancer (CRC). However, the role of MCs in the TME is controversially discussed as either pro- or anti-tumorigenic. Genetically engineered mouse models (GEMMs) are the most frequently used in vivo models for human CRC research. In the murine intestine there are at least three different MC subtypes: interepithelial mucosal mast cells (ieMMCs), lamina proprial mucosal mast cells (lpMMCs) and connective tissue mast cells (CTMCs). Interepithelial mucosal mast cells (ieMMCs) in (pre-)neoplastic intestinal formalin-fixed paraffin-embedded (FFPE) specimens of mouse models (total lesions n = 274) and human patients (n = 104) were immunohistochemically identified and semiquantitatively scored. Scores were analyzed along the adenoma-carcinoma sequence in humans and 12 GEMMs of small and large intestinal cancer. The presence of ieMMCs was a common finding in intestinal adenomas and carcinomas in mice and humans. The number of ieMMCs decreased in the course of colonic adenoma-carcinoma sequence in both species (p < 0.001). However, this dynamic cellular state was not observed for small intestinal murine tumors. Furthermore, ieMMC scores were higher in GEMMs with altered Wnt signaling (active β-catenin) than in GEMMs with altered MAPK signaling and wildtypes (WT). In conclusion, we hypothesize that, besides stromal MCs (lpMMCs/CTMCs), particularly the ieMMC subset is important for onset and progression of intestinal neoplasia and may interact with the adjacent neoplastic epithelial cells in dependence on the molecular environment. Moreover, our study indicates the need for adequate GEMMs for the investigation of the intestinal immunologic TME.

Advances in tests for colorectal cancer screening and diagnosis

INTRODUCTION

Colorectal cancer (CRC) is the second leading cause of cancer-related deaths globally. Nonetheless, with early detection of CRC or its precancerous lesions, mortality, and CRC incidence can be reduced. Although colonoscopy is currently the gold standard for CRC screening and diagnosis, its invasive nature, and troublesome bowel preparation deter patient participation. Therefore, there is a need to expand the use of noninvasive or minimally invasive methods to increase patient compliance.

AREAS COVERED

This review summarizes advances in different methods for CRC screening, including stool bacterial and metagenomic markers, fecal proteins, genetic and epigenetic markers in blood and stools, and imaging modalities. The cost-effectiveness of these methods is also discussed. FIT is more cost-effective compared to virtual colonoscopy, mSEPT9 test, and Multitarget Stool DNA test, while the cost-effectiveness of other noninvasive methods requires further evaluation.

EXPERT OPINION

Recent evidence has well demonstrated the usefulness of gut microbiome and certain fecal bacterial markers in the noninvasive diagnosis of CRC and its precancerous lesions. Many of the fecal biomarkers, from host cells or the gut environment, show better diagnostic sensitivity than FIT. New screening tests based on these fecal biomarkers can be expected to replace FIT with higher cost-effectiveness in the near future.

Colorectal microbiota after removal of colorectal cancer

The colonic microbiome has been implicated in the pathogenesis of colorectal cancer (CRC) and intestinal microbiome alterations are not confined to the tumour. Since data on whether the microbiome normalises or remains altered after resection of CRC are conflicting, we studied the colonic microbiota of patients after resection of CRC. We profiled the microbiota using 16S rRNA gene amplicon sequencing in colonic biopsies from patients after resection of CRC (n = 63) in comparison with controls (n = 52), subjects with newly diagnosed CRC (n = 93) and polyps (i = 28). The colonic microbiota after surgical resection remained significantly different from that of controls in 65% of patients. Genus-level profiling and beta-diversity confirmed two distinct groups of patients after resection of CRC: one with an abnormal microbiota similar to that of patients with newly diagnosed CRC and another similar to non-CRC controls. Consumption levels of several dietary ingredients and cardiovascular drugs co-varied with differences in microbiota composition suggesting lifestyle factors may modulate differential microbiome trajectories after surgical resection. This study supports investigation of the colonic microbiota as a marker of risk for development of CRC.

Colorectal Cancer: A Review of Carcinogenesis, Global Epidemiology, Current Challenges, Risk Factors, Preventive and Treatment Strategies

Colorectal cancer (CRC) is the second most deadly cancer. Global incidence and mortality are likely to be increased in the coming decades. Although the deaths associated with CRC are very high in high-income countries, the incidence and fatalities related to CRC are growing in developing countries too. CRC detected early is entirely curable by surgery and subsequent medications. However, the recurrence rate is high, and cancer drug resistance increases the treatment failure rate. Access to early diagnosis and treatment of CRC for survival is somewhat possible in developed countries. However, these facilities are rarely available in developing countries. Highlighting the current status of CRC, its development, risk factors, and management is crucial in creating public awareness. Therefore, in this review, we have comprehensively discussed the current global epidemiology, drug resistance, challenges, risk factors, and preventive and treatment strategies of CRC. Additionally, there is a brief discussion on the CRC development pathways and recommendations for preventing and treating CRC.

Discriminating Potential Genetic Markers for Complete Response and Non-Complete Response Patients to Neoadjuvant Chemotherapy with Locally Advanced Rectal Cancer

Background: Neoadjuvant chemoradiotherapy (nCRT) prior to surgery is considered standard therapy for locally advanced rectal cancer. Unfortunately, most patients with rectal cancer are resistant to radiotherapy. This might be a genetic cause. The role of certain rectal cancer-causing genes has not been completely elucidated. This study aims to investigate the genes responsible for locally advanced rectal cancer patients not reacting to radiotherapy. Methods: Whole exome sequencing of the DNA samples was performed on the samples. Bioinformatic analysis on the subjects was established. Individual genetic information was screened to identify differently expressed genes that more frequently appeared in non-complete response (NCR) compared to complete response (CR) patients after nCRT. All variations were verified by Sanger sequencing. Results: Genotyping information and pathway analyses of the samples indicated genes such as FLCN, CALML5, and ANTXR1 to be commonly mutated in CR group, whereas genes such as GALNTL14, CNKSR1, ACD, and CUL3 were more commonly mutated in the NCR group. Chi-square test revealed some significant variants (<0.05) such as rs3744124 (FLCN), rs28365986 (ANTXR1), rs10904516 (CALML5), rs3738952 (CUL3), rs13394 and rs2293013 (PIH1D1), rs2274531 (GPA33), rs4963048 (BRSK2), rs17883366 (IL3RA), rs2297575 (PSMD5), rs2288101 (GALNT14), and rs11954652 (DCTN4). Conclusion: Identifying an array of genes that separate NCRs from CRs would lead to finding genetic biomarkers for early detection of rectal cancer patients that are resistant to nCRT. A further investigation to validate the significance of genetic biomarkers to segregate NCRs from CRs should be performed with a larger CRC dataset. Protein expression levels, as well as transcriptomic analysis, would also help us understand the mechanism of how these genes could play a role in preventing radiation therapy to patients. This would be essential to prevent redundant radiation therapy.

Single-cell transcriptomic profiling unravels the adenoma-initiation role of protein tyrosine kinases during colorectal tumorigenesis

The adenoma-carcinoma sequence is a well-accepted roadmap for the development of sporadic colorectal cancer. However, cellular heterogeneity in aberrant epithelial cells limits our understanding of carcinogenesis in colorectal tissues. Here, we performed a single-cell RNA sequencing survey of 54,788 cells from patient-matched tissue samples, including blood, normal tissue, para-cancer, polyp, and colorectal cancer. At each stage of carcinogenesis, we characterized cell types, transcriptional signatures, and differentially expressed genes of distinct cell populations. The molecular signatures of epithelial cells at normal, benign, and malignant stages were defined at the single-cell scale. Adenoma and carcinoma precursor cell populations were identified and characterized followed by validation with large cohort biopsies. Protein tyrosine kinases (PTKs) BMX and HCK were identified as potential drivers of adenoma initiation. Specific BMX and HCK upregulations were observed in adenoma precursor cell populations from normal and adenoma biopsies. Overexpression of BMX and HCK significantly promoted colorectal epithelial cell proliferation. Importantly, in the organoid culture system, BMX and HCK upregulations resulted in the formation of multilayered polyp-like buds protruding towards the organoid lumen, mimicking the pathological polyp morphology often observed in colorectal cancer. Molecular mechanism analysis revealed that upregulation of BMX or HCK activated the JAK-STAT pathway. In conclusion, our work improved the current knowledge regarding colorectal epithelial evolution during carcinogenesis at the single-cell resolution. These findings may lead to improvements in colorectal cancer diagnosis and treatment.

Adenoma and serrated lesion detection with distal attachment in screening colonoscopy: a randomized controlled trial

BACKGROUND

Adenoma detection rate (ADR) is the single most important measure of quality in colonoscopy, but little is known about the detection rate of serrated lesions (SLDR). To improve ADR, Endocuff Vision (EV) can be used. Studies have shown differing results as to the effect on ADR; an effect on SLDR has not been shown. To investigate the effect of Endocuff Vision on ADR in a screening population, this randomized controlled open label trial with concealed allocation was performed. Randomization to trial group was carried out by the endoscopist using prepared numbered envelopes.

METHODS

Patients referred as part of the national bowel screening program at Regional Hospital Herning, Denmark were recruited and allocated to one of two groups: Endocuff Vision colonoscopy (EVC) and standard colonoscopy (SC). Outcomes were ADR, mean number, site, and size of lesions per procedure. SLDR as outcome was added after inclusion had begun.

RESULTS

A total of 1178 participants were included, with 1166 (EVC 583 and SC 583) available for analysis. There was no clinical relevant difference in ADR (59.2% [CI 55.1; 63.1] v 60.5% [CI 56.5; 64.4]) or SLDR (13.0% [CI 10.5; 16.0] v 10.3% [CI 8.0; 13.0]) between groups. More serrated lesions were found per procedure (MSP) (0.2 v 0.1, IRR 57% [CI 17; 109]. Removal rate of EV was similar in the two study groups.

CONCLUSION

We found no significant effects of the use of Endocuff Vision on ADR, when compared to standard colonoscopy, but more serrated lesions were detected in the Endocuff group.

TRIAL REGISTRATION

Clinical Trials NCT04651062.

Sequentially calibrating a Bayesian microsimulation model to incorporate new information and assumptions

BACKGROUND

Microsimulation models are mathematical models that simulate event histories for individual members of a population. They are useful for policy decisions because they simulate a large number of individuals from an idealized population, with features that change over time, and the resulting event histories can be summarized to describe key population-level outcomes. Model calibration is the process of incorporating evidence into the model. Calibrated models can be used to make predictions about population trends in disease outcomes and effectiveness of interventions, but calibration can be challenging and computationally expensive.

METHODS

This paper develops a technique for sequentially updating models to take full advantage of earlier calibration results, to ultimately speed up the calibration process. A Bayesian approach to calibration is used because it combines different sources of evidence and enables uncertainty quantification which is appealing for decision-making. We develop this method in order to re-calibrate a microsimulation model for the natural history of colorectal cancer to include new targets that better inform the time from initiation of preclinical cancer to presentation with clinical cancer (sojourn time), because model exploration and validation revealed that more information was needed on sojourn time, and that the predicted percentage of patients with cancers detected via colonoscopy screening was too low.

RESULTS

The sequential approach to calibration was more efficient than recalibrating the model from scratch. Incorporating new information on the percentage of patients with cancers detected upon screening changed the estimated sojourn time parameters significantly, increasing the estimated mean sojourn time for cancers in the colon and rectum, providing results with more validity.

CONCLUSIONS

A sequential approach to recalibration can be used to efficiently recalibrate a microsimulation model when new information becomes available that requires the original targets to be supplemented with additional targets.

Colonic Chicken Skin Mucosa Surrounding Colon Polyps Is an Endoscopic Predictive Marker for Colonic Neoplastic Polyps

Background/Aims

Narrow band imaging provides an accurate diagnosis of colonic polyps. However, these diagnostic modalities are not used as standard endoscopic tools in most institutions. This study aims to investigate whether the chicken skin mucosa (CSM) surrounding the colon polyp yields additional information about colorectal polyps, including histological differentiation of neoplastic and non-neoplastic polyps, under conventional white light colonoscopy.

Methods

This study prospectively observed 173 patients who underwent endoscopic polypectomy and reviewed the clinical data and pathologic reports of 313 polyps from a university hospital. Two endoscopists each performed colonoscopy and polypectomy and assessed the CSM. The association between CSM surrounding colorectal polyps and histology was analyzed.

Results

The majority (91.3%) of CSM-positive polyps were neoplastic (sensitivity, 37.90%; specificity, 86.15%; p<0.001). In logistic regression, the neoplastic polyps were associated with positive CSM (adjusted odds ratio [OR], 3.51; 95% confidence interval [CI], 1.45 to 9.25; p=0.007), protruded polyps (adjusted OR, 4.85; 95% CI, 1.65 to 17.23; p=0.008), and neoplastic histology–associated pit pattern (pit III, IV, and V) (adjusted OR, 10.14; 95% CI, 4.85 to 22.12; p=0.000). Furthermore, advanced adenomas were associated with positive CSM (adjusted OR, 5.64; 95% CI, 1.77 to 20.28; p=0.005), protruded polyps (adjusted OR, 3.30; 95% CI, 1.15 to 9.74; p= 0.026), and ≥10 cm polyp size (adjusted OR, 18.56; 95% CI, 3.89 to 147.01; p=0.001).

Conclusions

Neoplastic and advanced polyps were associated with CSM-positive polyps. These findings suggest that CSM is a useful marker in differentiating neoplastic polyps and advanced polyps under conventional white colonoscopy.

Small sessile serrated polyps might not be at a higher risk for future advanced neoplasia than low-risk adenomas or polyp-free groups

BACKGROUND

Polypectomy surveillance colonoscopy is recommended according to the risk stratification of initially removed polyps. This study aimed to evaluate the risk of advanced neoplasia following low-risk SSPs compared with that following LRAs and polyp-free groups.

MATERIALS AND METHODS

From September 2013 to August 2017, asymptomatic Koreans aged 50-75 years who underwent surveillance colonoscopy post-baseline colonoscopy were enrolled. The 1314 participants who met the study design criteria were stratified into three groups according to the presence of LRAs or low-risk SSPs. The rate of advanced neoplasia was then compared between groups by surveillance colonoscopy.

RESULTS

A total of 1314 participants were classified according to baseline colonoscopy findings: no polyp (n = 551), LRA (n = 707), and low-risk SSP (n = 56). All participants underwent surveillance colonoscopy after an average of 28.1 ± 8.7 months. The rate of advanced neoplasia at surveillance was not different between groups: no polyp group (13/551, 2.4%), LRA group (27/707, 3.8%), and low-risk SSP group (0/56, 0%). The LRA group exhibited a significantly higher rate of low- and high-risk polyps (47.5, 13.4%) than did the no polyp (35.6, 7.4%, p < .001, p = .001), but no significant differences to the low-risk SSP group (35.7, 7.1%, p = .117, p = .253), respectively.

CONCLUSIONS

Patients with low-risk SSPs were not at a higher risk of advanced neoplasia than LRA patients, even in the polyp-free group. We suggest that surveillance colonoscopy after the removal of low-risk SSPs is not required more often than for LRAs.

How can we better identify patients with rectal bleeding who are at high risk of colorectal cancer? An observational study

PURPOSE

Rectal bleeding is a common symptom of colorectal cancer. In this paper, we describe and evaluate the operation of a central access and triage system for patients with rectal bleeding, which uses a "high-risk"/ "low-risk" designation based on the referring doctor's subjective designation and a 10-item symptom checklist.

METHODS

A total of 1846 patients, referred between February 1, 2016, and December 31, 2018, were included. Exclusion criteria were the following: incorrect patient identification number, duplicate records, and pre-diagnosed gastrointestinal cancer. Data was obtained by chart review. Sensitivity, specificity, and positive and negative predictive values were calculated for each item on the symptom checklist.

RESULTS

Eight hundred seventy-nine (48%) patients received endoscopy, and 37 (2%) were found to have cancer. Five hundred eighty-two (32%) patients were deemed high-risk. Twenty-nine (78%) of the patients with cancer were in the high-risk group. Patients in the high-risk group had a higher incidence of cancer (5.0% vs 0.6%, p < 0.001) and shorter waits to endoscopy (201 vs 292 days). Patients designated as high-risk by the referring physician had a relative risk of 22.3 compared to those designated as low-risk. Patients deemed high-risk by the symptom checklist had a relative risk of 3.5 compared to low-risk patients.

CONCLUSION

Our system stratified 29/37 (78%) of the patients found to have cancer as high-risk. A total of 8/37 (22%) patients with cancer were deemed low-risk. Our research has identified two variables (weight loss and anemia) which have been added to our referral symptom checklist. This study helped us identify areas for refinement of our triage system. These findings are of interest to physicians who treat colorectal cancer.

Adenoma to Colorectal Cancer Estimated Transition Rates Stratified by BMI Categories—A Cross-Sectional Analysis of Asymptomatic Individuals from Screening Colonoscopy Program

Simple Summary

Most colorectal cancers assumedly develop from precursor lesions, i.e., colorectal adenomas (adenoma-carcinoma sequence). Epidemiological and clinical data supporting this hypothesis are limited. Therefore, the aim of the present study was to estimate relative dynamics of colorectal adenoma-carcinoma sequence for groups of screenees stratified by body mass. We have analyzed 163,129 individuals that underwent screening colonoscopy and calculated adjusted prevalences of colorectal adenomas and colorectal. Based on that data we have found that obese individuals are more likely to develop adenomas, advanced adenomas and early CRC but less likely to progress to advanced CRC. Therefore, this study provides new evidence that obesity paradox exists for colorectal cancer.

Abstract

Most colorectal cancers (CRC) assumedly develop from precursor lesions, i.e., colorectal adenomas (adenoma-carcinoma sequence). Epidemiological and clinical data supporting this hypothesis are limited. Therefore, the aim of the present study is to estimate relative dynamics of colorectal adenoma-carcinoma sequence for groups of screenees stratified by BMI (body mass index) based on prevalence data from Polish Colonoscopy Screening Program (PCSP). We performed a cross-sectional analysis of database records of individuals who entered the national opportunistic colonoscopy screening program for CRC in Poland. We calculated prevalence of adenomas and CRCs adjusted for sex, 5-year age group, family history of CRC, smoking, diabetes and use of aspirin, hormonal therapy and proton-pump inhibitors use. Thereafter we calculated estimated transition rate (eTR) with confidence intervals (CIs) defined as adjusted prevalence of more advanced lesion divided by adjusted prevalence of less advanced lesion. All analyzes were stratified according to the BMI categories: normal (BMI 18.0 to <25.0), overweight (BMI 25.0 to <30.0) and obese (BMI ≥ 30.0). Results are reported in the same respective order. After exclusions we performed analyses on 147,385 individuals. We found that prevalence of non-advanced adenomas is increasing with BMI category (12.19%, 13.81%, 14.70%, respectively; p < 0.001). Prevalence of advanced adenomas was increasing with BMI category (5.20%, 5.77%, 6.61%, respectively; p < 0.001). Early CRCs prevalence was the highest for obese individuals (0.55%) and the lowest for overweight individuals (0.44%) with borderline significance (p = 0.055). For advanced CRC we found that prevalence seems to be inversely related to BMI category, however no statistically significant differences were observed (0.35%, 0.31%, 0.28%; p = 0.274). eTR for non-advanced adenoma to advanced adenoma is higher for obese individuals than for overweight individuals with bordering CIs (42.65% vs. 41.81% vs. 44.95%) eTR for advanced adenoma to early CRC is highest for normal individuals, however CIs are overlapping with remaining BMI categories (9.02% vs. 7.67% vs. 8.39%). eTR for early CRC to advanced CRC is lower for obese individuals in comparison to both normal and overweight individuals with marginally overlapping CIs (73.73% vs. 69.90% vs. 50.54%). Obese individuals are more likely to develop adenomas, advanced adenomas and early CRC but less likely to progress to advanced CRC. Therefore, this study provides new evidence that obesity paradox exists for colorectal cancer.

Too Good to Be True? Evaluation of Colonoscopy Sensitivity Assumptions Used in Policy Models

BACKGROUND

Models can help guide colorectal cancer (CRC) screening policy. While models are carefully calibrated and validated, there is less scrutiny of assumptions about test performance.

METHODS

We examined the validity of the CRC-SPIN model and colonoscopy sensitivity assumptions. Standard sensitivity assumptions, consistent with published decision analyses, assume sensitivity equal to 0.75 for diminutive adenomas (<6mm), 0.85 for small adenomas (6-10mm), 0.95 for large adenomas ( {greater than or equal to} 10mm), and 0.95 for preclinical cancer. We also selected adenoma sensitivity that resulted in more accurate predictions. Targets were drawn from the Wheat Bran Fiber study. We examined how well the model predicted outcomes measured over a three-year follow-up period, including: the number of adenomas detected, the size of the largest adenoma detected, and incident CRC.

RESULTS

Using standard sensitivity assumptions, the model predicted adenoma prevalence that was too low (42.5% versus 48.9% observed, with 95% confidence interval 45.3%-50.7%) and detection of too few large adenomas (5.1% versus 14.% observed, with 95% confidence interval 11.8%-17.4%). Predictions were close to targets when we set sensitivities to 0.20 for diminutive adenomas, 0.60 for small adenomas, 0.80 for 10-20mm adenomas, and 0.98 for adenomas 20mm and larger.

CONCLUSIONS

Colonoscopy may be less accurate than currently assumed, especially for diminutive adenomas. Alternatively, the CRC-SPIN model may not accurately simulate onset and progression of adenomas in higher-risk populations.

IMPACT

Misspecification of either colonoscopy sensitivity or disease progression in high-risk populations may impact the predicted effectiveness of CRC screening. When possible, decision analyses used to inform policy should address these uncertainties.

Metagenomic analysis of primary colorectal carcinomas and their metastases identifies potential microbial risk factors

The paucity of microbiome studies at intestinal tissues has contributed to a yet limited understanding of potential viral and bacterial cofactors of colorectal cancer (CRC) carcinogenesis or progression. We analysed whole-genome sequences of CRC primary tumours, their corresponding metastases and matched normal tissue for sequences of viral, phage and bacterial species. Bacteriome analysis showed Fusobacterium nucleatum, Streptococcus sanguinis, F. Hwasookii, Anaerococcus mediterraneensis and further species enriched in primary CRCs. The primary CRC of one patient was enriched for F. alocis, S. anginosus, Parvimonas micra and Gemella sp. 948. Enrichment of Escherichia coli strains IAI1, SE11, K-12 and M8 was observed in metastases together with coliphages enterobacteria phage φ80 and Escherichia phage VT2φ_272. Virome analysis showed that phages were the most preponderant viral species (46%), the main families being Myoviridae, Siphoviridae and Podoviridae. Primary CRCs were enriched for bacteriophages, showing five phages (Enterobacteria, Bacillus, Proteus, Streptococcus phages) together with their pathogenic hosts in contrast to normal tissues. The most frequently detected, and Blast-confirmed, viruses included human endogenous retrovirus K113, human herpesviruses 7 and 6B, Megavirus chilensis, cytomegalovirus (CMV) and Epstein-Barr virus (EBV), with one patient showing EBV enrichment in primary tumour and metastases. EBV was PCR-validated in 80 pairs of CRC primary tumour and their corresponding normal tissues; in 21 of these pairs (26.3%), it was detectable in primary tumours only. The number of viral species was increased and bacterial species decreased in CRCs compared with normal tissues, and we could discriminate primary CRCs from metastases and normal tissues by applying the Hutcheson t-test on the Shannon indices based on viral and bacterial species. Taken together, our results descriptively support hypotheses on microorganisms as potential (co)risk factors of CRC and extend putative suggestions on critical microbiome species in CRC metastasis.

Gastrointestinal polyposis with associated cutaneous manifestations

Cutaneous findings are commonly associated with underlying gastrointestinal disorders and, in many instances, may be the first manifestation. Many such syndromes have incomplete penetrance and variable expressivity, making them difficult to recognise. Skin manifestations may be an easily recognised feature of the underlying disorder. Most of these syndromes are hereditary but not all are associated with malignancies; either benign or premalignant extraintestinal lesions can be the initial manifestation. Some involve a single organ system, while others involve multiple organs of the gastrointestinal tract. In this review, we have focused on Lynch syndrome (hereditary nonpolyposis colon cancer and Muir-Torre syndrome), familial adenomatous polyposis, the hamartomatous polyposis syndromes that include Peutz-Jeghers syndrome and the PTEN hamartoma syndromes, which include Cowden syndrome and Bannayan-Riley-Ruvalcaba syndrome and, lastly, Cronkhite-Canada syndrome, which is not heritable. Some of these are associated with colorectal cancer, of which 15% are heritable. The majority are inherited in an autosomal dominant fashion. These syndromes are uncommon. However, because of the strong association with the cutaneous findings, early detection and screening may be possible and are key to decreasing the morbidity and mortality associated with them, for both the patient and family members. The clinical findings, epidemiological findings, underlying genetic alterations and pathological findings are reviewed.

Chronic Viral Hepatitis Is Associated with Colorectal Neoplasia: A Systematic Review and Meta-Analysis

BACKGROUND

Chronic viral hepatitis is associated with a wide range of extrahepatic diseases; however, evidence on a link between chronic viral hepatitis and colorectal neoplasia is still lacking.

AIMS

To analyze the association between chronic viral hepatitis and prevalence of colorectal neoplasia.

METHODS

A systematic review of articles published in the MEDLINE, EMBASE, and Cochrane Library between 2000 and 2020 was performed. Subgroup analyses based on the types of colorectal neoplasia and the etiology of chronic viral hepatitis were conducted.

RESULTS

Twelve eligible studies with 48,428 hepatitis B virus (HBV) patients and 46,561 hepatitis C virus (HCV) patients were included. Chronic viral hepatitis was significantly associated with an increased risk of both colorectal adenoma (odds ratio [OR], 1.53; 95% confidence interval [CI], 1.16-2.02; I² = 83%) and colorectal cancer (CRC) (OR, 1.32; 95% CI, 1.08-1.61; I² = 94%). The etiology of chronic viral hepatitis was an independent factor related to heterogeneity for CRC subgroup analysis revealed an increased risk of CRC in both HBV (OR, 1.18; 95% CI, 1.09-1.27; I² = 37%) and HCV (OR, 1.88; 95% CI, 1.78-1.97; I² = 0%). HCV was associated with an increased risk of colorectal adenoma (OR, 1.48; 95% CI, 1.22-1.79; I² = 0%); however, HBV was not associated with an increased risk of colorectal adenoma and had considerable heterogeneity (OR, 1.65; 95% CI, 0.88-3.09; I² = 90%).

CONCLUSION

Our meta-analysis showed that chronic viral hepatitis is associated with an increased risk of colorectal neoplasia. The strategy of stricter screening colonoscopy may benefit from patients with chronic viral hepatitis.

The evolution and ecology of benign tumors

Tumors are usually classified into two main categories - benign or malignant, with much more attention being devoted to the second category given that they are usually associated with more severe health issues (i.e., metastatic cancers). Here, we argue that the mechanistic distinction between benign and malignant tumors has narrowed our understanding of neoplastic processes. This review provides the first comprehensive discussion of benign tumors in the context of their evolution and ecology as well as interactions with their hosts. We compare the genetic and epigenetic profiles, cellular activities, and the involvement of viruses in benign and malignant tumors. We also address the impact of intra-tumoral cell composition and its relationship with the tumoral microenvironment. Lastly, we explore the differences in the distribution of benign and malignant neoplasia across the tree of life and provide examples on how benign tumors can also affect individual fitness and consequently the evolutionary trajectories of populations and species. Overall, our goal is to bring attention to the non-cancerous manifestations of tumors, at different scales, and to stimulate research on the evolutionary ecology of host-tumor interactions on a broader scale. Ultimately, we suggest that a better appreciation of the differences and similarities between benign and malignant tumors is fundamental to our understanding of malignancy both at mechanistic and evolutionary levels.

Genomic profiling of intestinal/mixed-type superficial non-ampullary duodenal epithelial tumors

Background and Aim

The mechanism underlying carcinogenesis and the genomic features of superficial non‐ampullary duodenal epithelial tumors (SNADETs) have not been elucidated in detail. In this study, we examined the genomic features of incipient SNADETs, such as small lesions resected via endoscopic treatment, using next‐generation sequencing (NGS).

Methods

Twenty consecutive patients who underwent endoscopic treatment for SNADETs of less than 20 mm between January and December 2017 were enrolled. Targeted genomic sequencing was performed through NGS using a panel of 160 cancer‐related genes. Furthermore, the alteration/mutation frequencies in SNADETs were examined.

Results

The maximum size of the SNADETs examined in this study was 12 mm in diameter. Five SNADETs were classified as low‐grade dysplasia (LGD) tumors, while 14 SNADETs were classified as high‐grade dysplasia tumors. Only one carcinoma in situ was detected. NGS data for 16 samples were obtained. APC alterations were detected in 81% of samples (13/16). KRAS, BRAF, and TP53 alterations were detected in 25% (4/16), 18.8% (3/16), and 6.3% (1/16) of cases, respectively.

Conclusion

We detected APC alterations in most small SNADETs resected via endoscopic treatment, from LGD to carcinoma samples. Even in SNADETs classified as small LGD exhibited KRAS and BRAF alterations.

Meaningful words in rectal MRI synoptic reports: How "polypoid" may be prognostic

PURPOSE

This study explored the clinicopathologic outcomes of rectal tumor morphological descriptors used in a synoptic rectal MRI reporting template and determined that prognostic differences were observed.

METHODS

This retrospective study was conducted at a comprehensive cancer center. Fifty patients with rectal tumors for whom the synoptic descriptor "polypoid" was chosen by three experienced radiologists were compared with ninety comparator patients with "partially circumferential" and "circumferential" rectal tumors. Two radiologists re-evaluated all cases. The outcome measures were agreement among two re-interpreting radiologists, clinical T staging with MRI (mrT) and descriptive nodal features, and degrees of wall attachment of tumors (on MRI) compared with pathological (p) T and N stage when available.

RESULTS

Re-evaluation by two radiologists showed moderate to excellent agreement in tumor morphology, presence of a pedicle, and degree of wall attachment (k = 0.41-0.76) and excellent agreement on lymph node presence and size (ICC = 0.83-0.91). Statistically significant lower mrT stage was noted for polypoid morphology, wherein 98% were mrT1/2, while only 7% and 2% of partially circumferential and circumferential tumors respectively were mrT1/2. Pathologic T and N stages among the three morphologies also differed significantly, with only 14% of polypoid cases higher than stage pT2 compared to 48% of partially circumferential cases and 60% of circumferential cases.

CONCLUSION

Using a "polypoid" morphology in rectal cancer MRI synoptic reports revealed a seemingly distinct phenotype with lower clinical and pathologic T and N stages when compared with alternative available descriptors.

PRECIS

"Polypoid" morphology in rectal cancer confers a lower clinical and pathologic T and N stage and may be useful in determining whether to proceed with surgery versus neoadjuvant treatment.

RNA-Sequencing Based microRNA Expression Signature of Colorectal Cancer: The Impact of Oncogenic Targets Regulated by miR-490-3p

To elucidate novel aspects of the molecular pathogenesis of colorectal cancer (CRC), we have created a new microRNA (miRNA) expression signature based on RNA-sequencing. Analysis of the signature showed that 84 miRNAs were upregulated, and 70 were downregulated in CRC tissues. Interestingly, our signature indicated that both guide and passenger strands of some miRNAs were significantly dysregulated in CRC tissues. These findings support our earlier data demonstrating the involvement of miRNA passenger strands in cancer pathogenesis. Our study focused on downregulated miR-490-3p and investigated its tumor-suppressive function in CRC cells. We successfully identified a total of 38 putative oncogenic targets regulated by miR-490-3p in CRC cells. Among these targets, the expression of three genes (IRAK1: p = 0.0427, FUT1: p = 0.0468, and GPRIN2: p = 0.0080) significantly predicted 5-year overall survival of CRC patients. Moreover, we analyzed the direct regulation of IRAK1 by miR-490-3p, and its resultant oncogenic function in CRC cells. Thus, we have clarified a part of the molecular pathway of CRC based on the action of tumor-suppressive miR-490-3p. This new miRNA expression signature of CRC will be a useful tool for elucidating new molecular pathogenesis in this disease.

Ampullary Carcinoma: An Overview of a Rare Entity and Discussion of Current and Future Therapeutic Challenges

Ampullary carcinomas (ACs) represent a rare entity, accounting for approximately 0.2% of all gastrointestinal solid tumors and 20% of all periampullary cancers (PACs). Unfortunately, few data are available regarding the optimal therapeutic strategy for ACs due to their rarity, and physicians frequently encounter significant difficulties in the management of these malignancies. In this review, we will provide an overview of current evidence on AC, especially focusing on biological features, histological characteristics, and available data guiding present and future therapeutic strategies for these rare, and still barely known, tumors.

The integrated screening action model (I-SAM): A theory-based approach to inform intervention development

Screening can reduce deaths if the people invited participate. However, good uptake is hard to achieve, and our current approaches are failing to engage the most vulnerable. A coherent model of screening behaviour to guide our understanding and intervention development is yet to be established. The present aim was to propose an Integrated Screening Action Model (I-SAM) to improve screening access. The I-SAM synthesises existing models of health behaviour and empirical evidence. The I-SAM was developed following: i) an appraisal of the predominant models used within the screening literature; ii) the integration of the latest knowledge on behaviour change; with iii) the empirical literature, to inform the development of a theory-based approach to intervention development. There are three key aspects to the I-SAM: i) a sequence of stages that people pass through in engaging in screening behaviour (based on the Precaution Adoption Process Model); ii) screening behaviour is shaped by the interaction between participant and environmental influences (drawing from the Access Framework); and iii) targets for intervention should focus on the sources of behaviour - 'capability', 'opportunity', and 'motivation' (based on the COM-B Model). The I-SAM proposes an integrated model to support our understanding of screening behaviour and to identify targets for intervention. It will be an iterative process to test and refine the I-SAM and establish its value in supporting effective interventions to improve screening for all.

Recent Advances in Molecular Imaging of Colorectal Tumors

BACKGROUND

Recent endoscopic studies have revealed that small colorectal tumors are often overlooked during colonoscopy, indicating that more sensitive detection methods are needed.

SUMMARY

Molecular imaging has received considerable attention as a new endoscopic technique with high sensitivity. It generally employs a fluorescence-labeled compound that specifically binds to a molecule on the tumor. Fluorescent probes for molecular imaging are largely classified as 2 types: a fluorescence-labeled antibody targeting a molecule specifically expressed on the tumor cell surface such as epidermal growth factor receptor or vascular endothelial growth factor (VEGF); and a fluorescence-labeled small molecule compound targeting a molecule specifically expressed in tumor cells including c-Met, glutathione S-transferase, γ-glutamyltranspeptidase, cathepsin, or endothelin A receptor. These probes successfully detected colorectal tumors in several animal studies. Moreover, 3 recent human clinical trials evaluating endoscopic molecular imaging for colorectal tumors have been reported. In one study, a Cy5-labeled synthetic peptide against c-Met was developed, and fluorescent endoscopic observation with this probe detected a greater number of colorectal adenomas than with white light observation. Another trial used IR800-labeled anti-VEGF antibody, which sensitively detected human colorectal adenomas by fluorescent endoscopy. Last, a fluorescent probe with synthetic peptide against BRAF-positive cells was able to visualize sessile serrated lesions. The fluorescent probes accumulated at very high levels in colorectal tumor cells but at lower levels in surrounding nonneoplastic mucosa. Key Messages: We expect that molecular imaging techniques with fluorescent probes will soon lead to the establishment of a highly sensitive endoscopic method for colorectal tumor detection.

Neonatal Nav1.5 Protein Expression in Human Colorectal Cancer: Immunohistochemical Characterization and Clinical Evaluation

Voltage-gated Na+ channels (VGSCs) are expressed widely in human carcinomas and play a significant role in promoting cellular invasiveness and metastasis. However, human tissue-based studies and clinical characterization are lacking. In several carcinomas, including colorectal cancer (CRCa), the predominant VGSC is the neonatal splice variant of Nav1.5 (nNav1.5). The present study was designed to determine the expression patterns and clinical relevance of nNav1.5 protein in human CRCa tissues from patients with available clinicopathological history. The immunohistochemistry was made possible by the use of a polyclonal antibody (NESOpAb) specific for nNav1.5. The analysis showed that, compared with normal mucosa, nNav1.5 expression occurred in CRCa samples (i) at levels that were significantly higher and (ii) with a pattern that was more delineated (i.e., apical/basal or mixed). A surprisingly high level of nNav1.5 protein expression also occurred in adenomas, but this was mainly intracellular and diffuse. nNav1.5 showed a statistically significant association with TNM stage, highest expression being associated with TNM IV and metastatic status. Interestingly, nNav1.5 expression co-occurred with other biomarkers associated with metastasis, including hERG1, KCa3.1, VEGF-A, Glut1, and EGFR. Finally, univariate analysis showed that nNav1.5 expression had an impact on progression-free survival. We conclude (i) that nNav1.5 could represent a novel clinical biomarker ('companion diagnostic') useful to better stratify CRCa patients and (ii) that since nNav1.5 expression is functional, it could form the basis of anti-metastatic therapies including in combination with standard treatments.

Role of artificial intelligence in multidisciplinary imaging diagnosis of gastrointestinal diseases

The use of artificial intelligence-based tools is regarded as a promising approach to increase clinical efficiency in diagnostic imaging, improve the interpretability of results, and support decision-making for the detection and prevention of diseases. Radiology, endoscopy and pathology images are suitable for deep-learning analysis, potentially changing the way care is delivered in gastroenterology. The aim of this review is to examine the key aspects of different neural network architectures used for the evaluation of gastrointestinal conditions, by discussing how different models behave in critical tasks, such as lesion detection or characterization (i.e. the distinction between benign and malignant lesions of the esophagus, the stomach and the colon). To this end, we provide an overview on recent achievements and future prospects in deep learning methods applied to the analysis of radiology, endoscopy and histologic whole-slide images of the gastrointestinal tract.

Targeting Metastatic Colorectal Cancer with Immune Oncological Therapies

Metastatic colorectal cancer carries poor prognosis, and current therapeutic regimes convey limited improvements in survival and high rates of detrimental side effects in patients that may not stand to benefit. Immunotherapy has revolutionised cancer treatment by restoring antitumoural mechanisms. However, the efficacy in metastatic colorectal cancer, is limited. A literature search was performed using Pubmed (Medline), Web of Knowledge, and Embase. Search terms included combinations of immunotherapy and metastatic colorectal cancer, primarily focusing on clinical trials in humans. Analysis of these studies included status of MMR/MSS, presence of combination strategies, and disease control rate and median overall survival. Evidence shows that immune checkpoint inhibitors, such as anti-PD1 and anti-PD-L1, show efficacy in less than 10% of patients with microsatellite stable, MMR proficient colorectal cancer. In the small subset of patients with microsatellite unstable, MMR deficient cancers, response rates were 40-50%. Combination strategies with immunotherapy are under investigation but have not yet restored antitumoural mechanisms to permit durable disease regression. Immunotherapy provides the potential to offer additional strategies to established chemotherapeutic regimes in metastatic colorectal cancer. Further research needs to establish which adjuncts to immune checkpoint inhibition can unpick resistance, and better predict which patients are likely to respond to individualised therapies to not just improve response rates but to temper unwarranted side effects.

Colorectal Cancer: From Genetic Landscape to Targeted Therapy

Colorectal cancer (CRC) is the third most common cancer type and the second cause of death worldwide. The advancement in understanding molecular pathways involved in CRC has led to new classifications based on the molecular characteristics of each tumor and also improved CRC management through the integration of targeted therapy into clinical practice. In this review, we will present the main molecular pathways involved in CRC carcinogenesis, the molecular classifications. The anti-VEGF and anti-EGFR therapies currently used in CRC treatment and those under clinical investigation will also be outlined, as well as the mechanisms of primary and acquired resistance to anti-EGFR monoclonal antibodies (cetuximab and panitumumab). Targeted therapy has led to great improvement in the treatment of metastatic CRC. However, there has been variability in CRC treatment outcomes due to molecular heterogeneity in colorectal tumors, which underscores the need for identifying prognostic and predictive biomarkers for CRC-targeted drugs.

Incidence of polyp formation following bariatric surgery

BACKGROUND

Multiple studies have linked obesity to an increased risk of cancer. The correlation is so strong that the national cancer prevention guidelines recommend weight loss for patients with obesity to reduce their risk of cancer. Bariatric surgery has been shown to be very effective in sustained weight loss. However, there have been mixed findings about bariatric surgery and its effects on the risk of colorectal cancer.

OBJECTIVE

This study sought to examine bariatric surgery patients and their risk of pre-cancerous or cancerous polyps to elucidate any risk factors or associations between bariatric surgery and colorectal cancer.

SETTING

A retrospective review of the academic medical center's bariatric surgery database was performed from January 2010 to January 2017. Patients who underwent medical or surgical weight loss and had a subsequent colonoscopy were included in the study. Positive colonoscopy findings were described as malignant or premalignant polyps.

METHODS

A total of 1777 patients were included, with 1360 in the medical group and 417 in the surgical group. Data analysis included patient demographics, co-morbidities, procedure performed, surgical approach, weight loss, and colonoscopy findings. A multivariate analysis was used to determine whether an association exists between weight loss and incidence of colorectal polyps, and if so, whether the association different for medical versus surgical weight loss.

RESULTS

A higher percentage of body mass index (BMI) reduction was seen in the surgical group. An overall comparison showed average reductions in BMI of 27.7% in the surgical group and 3.5% in the medical group (P < .0001). Patients with the greatest reduction in BMI, regardless of medical or surgical therapy, showed a lower incidence of precancerous and cancerous polyps (P = .041).

CONCLUSION

This study offers a unique approach in examining the incidence of colorectal polyps related to obesity. Patients with the greatest reduction in their BMI, more common in the surgical group, had a lower incidence of precancerous and cancerous polyps.

PD-L1 upregulation is associated with activation of the DNA double-strand break repair pathway in patients with colitic cancer

Ulcerative colitis (UC) is a DNA damage-associated chronic inflammatory disease; the DNA double-strand break (DSB) repair pathway participates in UC-associated dysplasia/colitic cancer carcinogenesis. The DSB/interferon regulatory factor-1 (IRF-1) pathway can induce PD-L1 expression transcriptionally. However, the association of PD-L1/DSB/IRF-1 with sporadic colorectal cancer (SCRC), and UC-associated dysplasia/colitic cancer, remains elusive. Therefore, we investigated the significance of the PD-L1/DSB repair pathway using samples from 17 SCRC and 12 UC patients with rare UC-associated dysplasia/colitic cancer cases by immunohistochemical analysis. We compared PD-L1 expression between patients with SCRC and UC-associated dysplasia/colitic cancer and determined the association between PD-L1 and the CD8+ T-cell/DSB/IRF-1 axis in UC-associated dysplasia/colitic cancer. PD-L1 expression in UC and UC-associated dysplasia/colitic cancer was higher than in normal mucosa or SCRC, and in CD8-positive T lymphocytes in UC-associated dysplasia/colitic cancer than in SCRC. Moreover, PD-L1 upregulation was associated with γH2AX (DSB marker) and IRF-1 upregulation in UC-associated dysplasia/colitic cancer. IRF-1 upregulation was associated with γH2AX upregulation in UC-associated dysplasia/colitic cancer but not in SCRC. Multicolour immunofluorescence staining validated γH2AX/IRF-1/PD-L1 co-expression in colitic cancer tissue sections. Thus, immune cell-induced inflammation might activate the DSB/IRF-1 axis, potentially serving as the primary regulatory mechanism of PD-L1 expression in UC-associated carcinogenesis.

Coexistence of the BRCA1 and KRAS mutations in a patient with salivary gland carcinoma arising in mediastinal mature teratoma

Teratoma with malignant transformation is a rare type of malignant teratoma. In the present case, we describe a patient with salivary gland carcinoma (SGC) generating in mediastinal mature teratoma. Next-generation sequencing showed BRCA1 and KRAS somatic mutations, which might be associated with malignant transformation of the mediastinal mature teratomas. To our knowledge, the present case is the first report of coexistence of BRCA1 and KRAS mutations in mature cystic teratoma with malignant transformation to SGC. And the tumor showed a good response to chemotherapy with cisplatin and paclitaxel according to the transformed histology.

Exploring polyps to colon carcinoma voyage: can blocking the crossroad halt the sequence?

Colorectal cancer is an important public health concern leading to significant cancer associate mortality. A vast majority of colon cancer arises from polyp which later follows adenoma, adenocarcinoma, and carcinoma sequence. This whole process takes several years to complete and recent genomic and proteomic technologies are identifying several targets involved in each step of polyp to carcinoma transformation in a large number of studies. Current text presents interaction network of targets involved in polyp to carcinoma transformation. In addition, important targets involved in each step according to network biological parameters are also presented. The functional overrepresentation analysis of each step targets and common top biological processes and pathways involved in carcinoma indicate several insights about this whole mechanism. Interaction networks indicate TP53, AKT1, GAPDH, INS, EGFR, and ALB as the most important targets commonly involved in polyp to carcinoma sequence. Though several important pathways are known to be involved in CRC, the central common involvement of PI3K-AKT indicates its potential for devising CRC management strategies. The common and central targets and pathways involved in polyp to carcinoma progression can shed light on its mechanism and potential management strategies. The data-driven approach aims to add valuable inputs to the mechanism of the years-long polyp-carcinoma sequence.

CYTOPLASMIC-MEMBRANE EGFR PREDICTS EXPANDED RAS MUTATION STATUS IN COLORECTAL CARCINOMAS?

BACKGROUND

Inhibitors of the epidermal growth factor (EGFR) represent an effective therapeutic option for patients with metastatic colorectal carcinoma, free of activating mutations in KRAS and NRAS. However, the research of mutations is of high cost and scarcely accessible. The expression of the EGFR by immunohistochemistry predicting the mutation status of the expanded RAS (KRAS and NRAS), may allow treatment by a diagnostic method less costly and more accessible.

AIM

Investigate the correlation between the clinical-pathological data, the cytoplasmic-membrane expression of the EGFR and the mutational status of the expanded RAS.

METHOD

A total of 139 patients with colorectal carcinoma from the archives of Instituto Goiano de Oncologia e Hematologia were evaluated.

RESULTS

Mutation of the expanded RAS was detected in 78 (56.1%) cases. The EGFR expression was stratified in 23 (16.5%) "positive", 49 (35.2%) "negative" and 67 (48.2%) "uncertain". No significant correlation was found between the mutational status of the RAS and the EGFR expression in comparison to age, gender, location, histological type, histological grade and stage. From 23 "positive" cases, 21 (91.3%) showed wild-type RAS gene, and 49 "negative", 41 (83.7%) presented mutation, resulting in a strong association between EGFR "positive", "negative" groups and the mutational status of the RAS (p<0.001), with 86.1% of accuracy.

CONCLUSIONS

The cytoplasmic-membrane analysis of the EGFR expression stratified into "positive", "negative" and "uncertain" predicts mutational status of the RAS in 51.7% of the cases (p<0.001), with 86.1% of accuracy.

Comprehensive Analysis of Differentially Expressed Long Noncoding RNA-mRNA in the Adenoma-Carcinoma Sequence of DNA Mismatch Repair Proficient Colon Cancer

DNA proficient mismatch repair colon cancer (pMMR CC) is the most common subtype of sporadic CC. We aimed to investigate the role of long noncoding RNAs (lncRNAs) in pMMR CC carcinogenesis. In the present study, we conducted transcriptomic analysis of lncRNAs-mRNAs in five low-grade intraepithelial neoplasia (LGIN), five high-grade intraepithelial neoplasia (HGIN), four pMMR CC, and five normal control (NC) tissues. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment pathway, and coexpression network analyses were performed to elucidate the functions of lncRNAs and mRNAs as well as their interactions. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to validate five dysregulated lncRNAs in a large set of colon tissues. Receiver-operating characteristic (ROC) curves were employed to evaluate the performance of the candidate lncRNAs. A set of 5783 differentially expressed lncRNAs and 4483 differentially expressed mRNAs were detected among the LGIN, HGIN, pMMR CC, and NC samples. These differentially expressed lncRNAs and mRNAs were assigned to 275 significant GO terms and 179 significant KEGG enriched pathways. qRT-PCR confirmed that the expression of five selected lncRNAs (ENST00000521815, ENST00000603052, ENST00000609220, NR_026543, and ENST00000545920) were consistent with the microarray data. ROC analysis showed that four lncRNAs (ENST00000521815, ENST00000603052, ENST00000609220, and NR_026543) had larger area under the ROC curve (AUC) values compared to serum carcinoembryonic antigens, thereby distinguishing NC from pMMR CC. In conclusion, several lncRNAs play various roles in the adenoma-carcinoma sequence and may serve as potential biomarkers for the early diagnosis of pMMR CC.

Effects of molecular markers on the treatment decision and prognosis of colorectal cancer: a narrative review

OBJECTIVE

To summarize the effects of molecular markers on the treatment decision and prognosis of colorectal cancer.

BACKGROUND

Colorectal cancer is a highly heterogeneous disease. Even colorectal cancers of the same pathological type and clinical stage may have significant differences in treatment efficacy and prognosis. There are three main molecular mechanisms for the occurrence and development of colorectal cancer: chromosomal instability (CIN) pathway, microsatellite instability (MSI), and CpG island methylate phenotype (CIMP). There are multiple molecular markers distributed on each pathway.

METHODS

We performed a literature search on the PubMed database for studies published in English (from the date of initiation of the database to the year of 2020) using the following subject terms: "colon cancer", "rectal cancer", "colorectal cancer", "molecular markers", "biomarkers", "treatment strategies", and "prognosis".

CONCLUSIONS

The different expression states of molecular markers have a significant impact on the treatment decision and prognosis of colorectal cancer. Main colorectal cancer molecular markers include MSI and some important genes. Individualized treatments for tumors with different molecular phenotypes have improved the treatment effectiveness for colorectal cancer. The rational use of molecular markers is valuable for treatment decision-making and the prognosis of patients with colorectal cancer.

Optimizing Loco Regional Management of Oligometastatic Colorectal Cancer: Technical Aspects and Biomarkers, Two Sides of the Same Coin

Colorectal cancer (CRC) is the third most common cancer worldwide and has a high rate of metastatic disease which is the main cause of CRC-related death. Oligometastatic disease is a clinical condition recently included in ESMO guidelines that can benefit from a more aggressive locoregional approach. This review focuses the attention on colorectal liver metastases (CRLM) and highlights recommendations and therapeutic locoregional strategies drawn from the current literature and consensus conferences. The different percutaneous therapies (radiofrequency ablation, microwave ablation, irreversible electroporation) as well as trans-arterial approaches (chemoembolization and radioembolization) are discussed. Ablation margins, the choice of the imaging guidance as well as characteristics of the different ablation techniques and other technical aspects are analyzed. A specific attention is then paid to the increasing role of biomarkers (in particular molecular profiling) and their role in the selection of the proper treatment for the right patient. In conclusion, in this review an up-to-date state of the art of the application of locoregional treatments on CRLM is provided, highlighting both technical aspects and the role of biomarkers, two sides of the same coin.

Influence of chronic inflammation on the malignant phenotypes and the plasticity of colorectal cancer cells

Sporadic adenoma or adenocarcinoma is often detected during endoscopic surveillance of patients with ulcerative colitis (UC). However, it is occasionally difficult to distinguish these neoplasms from dysplasia or colitis-associated cancers because of the influence of inflammation. However, the influence of inflammation on sporadic neoplasms is not well characterised. To assess this influence, we established a long-term inflammation model of colon cancer cells by inflammatory stimulation with tumour necrosis factor-α, flagellin and interleukin-1β for 60 weeks. Then, the malignant phenotypes were evaluated using the MTS assay, Annexin V fluorescence assay, cell migration assay and sphere formation assay. The influence of P53 function on these phenotypes was assessed with a TP53 mutation model using the CRISPR/Cas9 system. A long-term inflammation model of LS174T cells was established for the first time with continuous inflammatory signalling. Chronic inflammation induced apoptosis and suppressed the proliferation and stemness of these cancer cells via the action of P53. It also enhanced the invasiveness of LS174T cells. Moreover, these phenotypic changes and changes in inflammatory signalling were recoverable after the removal of inflammatory stimuli, suggesting that colon cancer cells have higher plasticity than normal intestinal epithelial cells. In conclusion, our results suggest that sporadic neoplasms in patients with UC are affected by chronic inflammation but are not essentially altered.

•

Chronic inflammation model of colon cancer cells is established for the first time.

•

Chronic inflammation (CI) suppresses the viability of cancer cells via P53.

•

CI also alters the malignant phenotypes: stemness and invasiveness.

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P53 mutation under CI acquires higher malignant phenotypes.

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Changes of malignant phenotypes are recoverable after the removal of CI.

A Dynamic Transcription Factor Signature Along the Colorectal Adenoma-Carcinoma Sequence in Patients With Co-Occurrent Adenoma and Carcinoma

Background

Colorectal carcinoma (CRC) often arises from benign adenoma after a stepwise accumulation of genetic alterations. Here, we profiled the dynamic landscapes of transcription factors (TFs) in the mucosa-adenoma-carcinoma progression sequence.

Methods

The transcriptome data of co-occurrent adenoma, carcinoma, and normal mucosa samples were obtained from GSE117606. Identification of differentially expressed TFs (DE-TFs) and subsequent function annotation were conducted in R software. Expression patterns of DE-TFs were clustered by Short Time-series Expression Miner software. Thereafter, modular co-expression analysis, Kaplan-Meier survival analysis, mutation profiling, and gene set enrichment analysis were conducted to investigate TF dynamics in colorectal tumorigenesis. Finally, tissue microarrays, including 51 tumors, 32 adenomas, and 53 normal tissues, were employed to examine the expression of significant candidates by immunohistochemistry staining.

Results

Compared to normal tissues, 20 (in adenoma samples) and 29 (in tumor samples) DE-TFs were identified. During the disease course, 28 expression patterns for DE-TFs and four co-expression modules were clustered. Notably, six DE-TFs, DACH1, GTF2IRD1, MEIS2, NR3C2, SOX9, and SPIB, were identified as having a dynamic signature along the colorectal adenoma-carcinoma sequence. The dynamic signature was of significance in GO enrichment, prognosis, and co-expression analysis. Among the 6-TF signature, the roles of GTF2IRD1, SPIB and NR3C2 in CRC progression are unclear. Immunohistochemistry validation showed that GTF2IRD1 enhanced significantly throughout the mucosa-adenoma-carcinoma sequence, while SPIB and NR3C2 kept decreasing in stroma during the disease course.

Conclusions

Our study provided a dynamic 6-TF signature throughout the course of colorectal mucosa-adenoma-carcinoma. These findings deepened the understanding of colorectal cancer pathogenesis.

Inflammation-Induced Tumorigenesis and Metastasis

Inflammation, especially chronic inflammation, plays a pivotal role in tumorigenesis and metastasis through various mechanisms and is now recognized as a hallmark of cancer and an attractive therapeutic target in cancer. In this review, we discuss recent advances in molecular mechanisms of how inflammation promotes tumorigenesis and metastasis and suppresses anti-tumor immunity in various types of solid tumors, including esophageal, gastric, colorectal, liver, and pancreatic cancer as well as hematopoietic malignancies.

Platelet-to-lymphocyte ratio and C-reactive protein as markers for colorectal polyp histological type

Background

The platelet-to-lymphocyte ratio (PLR) and C-reactive protein (CRP) level are markers that have been reported to predict the histological type of various tumors, and here, we evaluated their utility in predicting colorectal polyp histological types.

Methods

We retrospectively reviewed 172 patients with colorectal polyps who underwent endoscopic polypectomy. The associations between histological type and clinicopathologic parameters were assessed by multivariate analysis.

Results

The optimal PLR and CRP cut-off values were 113.32 and 0.39, respectively. The PLR (P = 0.002) and CRP (P = 0.009) values were associated with the histological type according to the univariate analysis, whereas low PLR (P ≤ 0.001) and CRP (P = 0.017) values were independent risk factors in the multivariate analysis together with maximum tumor diameter (P ≤ 0.001) and tumor number (P = 0.0014).

Conclusions

Preoperative PLR and CRP are correlated with the colorectal polyp histological type.

Fucoxanthin and Colorectal Cancer Prevention

Simple Summary

Colorectal cancer (CRC) is suggested to be preventable by certain food intakes. Fucoxanthin (Fx) is an anticancer agent contained abundantly in edible brown algae. However, epidemiological studies, in vivo and in vitro experiments for CRC, using Fx and Fx-rich foods, have not been fully outlined. To date, it has been reported that Fx, its metabolite of fucoxanthinol (FxOH) and Fx-rich algal extracts exerted anticancer potentials in human CRC cell lines, their cancer stem-cells-like spheroids and CRC animal models through a number of molecular mechanisms. Moreover, many in vivo experiments and interventional human trials have demonstrated that Fx, Fx-rich algal extracts and brown alga itself may improve CRC and/or certain risks, such as obesity, diabetes, metabolic syndrome, inflammation, oxidation, tumor microenvironment and/or gut microbiota. This review is the first report that summarizes the improving effects by Fx, FxOH and its rich brown algae for CRC and the risk factors.

Abstract

Colorectal cancer (CRC), which ranks among the top 10 most prevalent cancers, can obtain a good outcome with appropriate surgery and/or chemotherapy. However, the global numbers of both new cancer cases and death from CRC are expected to increase up to 2030. Diet-induced lifestyle modification is suggested to be effective in reducing the risk of human CRC; therefore, interventional studies using diets or diet-derived compounds have been conducted to explore the prevention of CRC. Fucoxanthin (Fx), a dietary carotenoid, is predominantly contained in edible brown algae, such as Undaria pinnatifida (wakame) and Himanthalia elongata (Sea spaghetti), which are consumed particularly frequently in Asian countries but also in some Western countries. Fx is responsible for a majority of the anticancer effects exerted by the lipophilic bioactive compounds in those algae. Interventional human trials have shown that Fx and brown algae mitigate certain risk factors for CRC; however, the direct mechanisms underlying the anti-CRC properties of Fx remain elusive. Fx and its deacetylated type “fucoxanthinol” (FxOH) have been reported to exert potential anticancer effects in preclinical cancer models through the suppression of many cancer-related signal pathways and the tumor microenvironment or alteration of the gut microbiota. We herein review the most recent studies on Fx as a potential candidate drug for CRC prevention.

Effects of Screenings in Reducing Colorectal Cancer Incidence and Mortality Differ by Polygenic Risk Scores

INTRODUCTION

Colorectal cancer (CRC) screening reduces CRC incidence and mortality. However, it is unclear whether the reduction in CRC risk may differ by genetic susceptibility.

METHODS

We evaluated this question in a cohort of 304,740 participants of European descent aged 50 years and older. Genetic susceptibility was measured using a polygenic risk score (PRS) constructed with risk variants identified in genomewide association studies. Cox models were used to estimate hazard ratios and 95% confidence intervals of CRC risk.

RESULTS

Over a median follow-up of 7.0 years, 2,261 incident CRC cases and 528 CRC deaths were identified. CRC screening was associated with a significantly reduced CRC incidence among individuals with a high (hazard ratio, 0.80; 95% confidence interval, 0.71-0.92) and intermediate PRS (0.84, 0.71-0.98) but not among those with a low PRS (1.03, 0.86-1.25; Pinteraction, 0.005). A similar but more evident difference was observed for mortality (Pinteraction, 0.046), with more than 30% reduced mortality observed in the high PRS group (0.69, 0.52-0.91). Among the younger group (age 50-60 years), CRC screenings were associated with a slightly (but nonsignificantly) elevated incidence and mortality in the low PRS group but a reduced risk in the high PRS group (Pinteraction, 0.043 [incidence]; 0.092 [mortality]). No significant interaction was observed in the older group (age > 60 years).

DISCUSSION

Individuals with a higher genetic risk benefited more substantially from CRC screenings than those with a lower risk. Our findings suggest that PRS may be used to develop personalized CRC screening to maximize its effect on CRC prevention.

Dietary inflammatory index and risk of colorectal adenoma: effect measure modification by race, nonsteroidal anti-inflammatory drugs, cigarette smoking and body mass index?

PURPOSE

To investigate if the association between dietary inflammatory potential and colorectal adenoma (CRA) is modified by race and factors known to modulate inflammation.

METHODS

We examined effect measure modification of race, nonsteroidal anti-inflammatory drugs (NSAIDs), cigarette smoking and body mass index (BMI) on the diet-CRA association by employing energy-adjusted dietary inflammatory index (E-DII™) to characterize dietary inflammatory potential among 587 cases and 1,313 controls participating in a colonoscopy screening-based cross-sectional study of CRA. Participants completed a food frequency questionnaire from which E-DII score was derived. E-DII score was calculated from 34 food parameters (constituents), utilizing an energy-adjusted global comparative database to compute z scores from which centered proportions were summed to create the score. CRA cases were defined as individuals whose colonoscopy detected at least one pathologically confirmed adenomatous polyp. Unconditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

A pro-inflammatory diet was not statistically significantly associated with elevated CRA risk (OR 1.07; 95% CI 0.97-1.19; p value = 0.18) in the multivariate regression model. NSAIDs use (OR_never-users 1.19; 95% CI 1.03-1.38; OR_ever-users 0.96; 95% CI 0.83-1.12; P_interaction = 0.04) and race (OR_{African Americans} 1.22; 95% CI 1.03-1.44; OR_{European Americans} 0.99; 95% CI 0.86-1.14; P_interaction = 0.14) appeared to modify the association, whereas cigarette smoking and BMI did not (P_interaction = 0.40 and 0.78, respectively).

CONCLUSION

NSAIDs use and race may modify the diet-CRA association. Further investigation in prospective cohort studies is warranted to confirm these findings.

Could diagnostic and therapeutic delay affect the prognosis of gastrointestinal primary malignancies in the COVID-19 pandemic era? A literature review

BACKGROUND

Emergency situations, as the Covid-19 pandemic that is striking the world nowadays, stress the national health systems which are forced to rapidly reorganizing their sources. Therefore, many elective diagnostic and surgical procedures are being suspended or significantly delayed. Moreover, patients might find it difficult to refer to physicians and delay the diagnostic and even the therapeutic procedures because of emotional or logistic problems. The effect of diagnostic and therapeutic delay on survival in patients affected by gastrointestinal malignancies is still unclear.

METHODS

We carried out a review of the available literature, in order to determine whether the delay in performing diagnosis and curative-intent surgical procedures affects the oncological outcomes in patients with oesophageal, gastric, colorectal cancers, and colorectal liver metastasis.

RESULTS

The findings indicate that for oesophageal, gastric and colon cancers delaying surgery up to 2 months after the end of the staging process does not worsen the oncological outcomes. Oesophageal cancer should undergo surgery within 7-8 weeks after the end of neoadjuvant chemoradiation. Rectal cancers should undergo surgery within 31 days after the diagnostic process and within 12 weeks after neoadjuvant therapy. Adjuvant therapy should start within 4 weeks after surgery, especially in gastric cancer; a delay up to 42 days may be allowed for oesophageal cancer undergoing adjuvant radiotherapy.

CONCLUSIONS

Gastrointestinal malignancies can be safely managed taking into account that reasonable delays of planned treatments appear a generally safe approach, not having a significant impact on long-term oncological outcome.