How Many Deaths from Colorectal Cancer Can Be Prevented by 2030? A Scenario-Based Quantification of Risk Factor Modification, Screening, and Treatment in Norway

Dysbiotic microbiome variation in colorectal cancer patients is linked to lifestyles and metabolic diseases

BACKGROUND

Differences in the composition and diversity of the gut microbial communities among individuals are influenced by environmental factors. However, there is limited research on factors affecting microbiome variation in colorectal cancer patients, who display lower inter-individual variations than that of healthy individuals. In this study, we examined the association between modifiable factors and the microbiome variation in colorectal cancer patients.

METHODS

A total of 331 colorectal cancer patients who underwent resection surgery at the Department of Surgery, Seoul National University Hospital between October 2017 and August 2019 were included. Fecal samples from colorectal cancer patients were collected prior to the surgery. Variations in the gut microbiome among patients with different lifestyles and metabolic diseases were examined through the network analysis of inter-connected microbial abundance, the assessment of the Anna Karenina principle effect for microbial stochasticity, and the identification of the enriched bacteria using linear discrimination analysis effect size. Associations of dietary diversity with microbiome variation were investigated using the Procrustes analysis.

RESULTS

We found stronger network connectivity of microbial communities in non-smokers, non-drinkers, obese individuals, hypertensive subjects, and individuals without diabetes than in their counterparts. The Anna Karenina principle effect was found for history of smoking, alcohol consumption, and diabetes (with significantly greater intra-sample similarity index), whereas obesity and hypertension showed the anti-Anna Karenina principle effect (with significantly lower intra-sample similarity index). We found certain bacterial taxa to be significantly enriched in patients of different categories of lifestyles and metabolic diseases using linear discrimination analysis. Diversity of food and nutrient intake did not shape the microbial diversity between individuals (p_Procrustes>0.05).

CONCLUSIONS

Our findings suggested an immune dysregulation and a reduced ability of the host and its microbiome in regulating the community composition. History of smoking, alcohol consumption, and diabetes were shown to affect partial individuals in shifting new microbial communities, whereas obesity and history of hypertension appeared to affect majority of individuals and shifted to drastic reductions in microbial compositions. Understanding the contribution of modifiable factors to microbial stochasticity may provide insights into how the microbiome regulates effects of these factors on the health outcomes of colorectal cancer patients.

Machine Learning in Colorectal Cancer Risk Prediction from Routinely Collected Data: A Review

The inclusion of machine-learning-derived models in systematic reviews of risk prediction models for colorectal cancer is rare. Whilst such reviews have highlighted methodological issues and limited performance of the models included, it is unclear why machine-learning-derived models are absent and whether such models suffer similar methodological problems. This scoping review aims to identify machine-learning models, assess their methodology, and compare their performance with that found in previous reviews. A literature search of four databases was performed for colorectal cancer prediction and prognosis model publications that included at least one machine-learning model. A total of 14 publications were identified for inclusion in the scoping review. Data was extracted using an adapted CHARM checklist against which the models were benchmarked. The review found similar methodological problems with machine-learning models to that observed in systematic reviews for non-machine-learning models, although model performance was better. The inclusion of machine-learning models in systematic reviews is required, as they offer improved performance despite similar methodological omissions; however, to achieve this the methodological issues that affect many prediction models need to be addressed.

Insights behind the Relationship between Colorectal Cancer and Obesity: Is Visceral Adipose Tissue the Missing Link?

Colorectal cancer (CRC) is a major health problem worldwide, with an estimated 1.9 million new cases and 915,880 deaths in 2020 alone. The etiology of CRC is complex and involves both genetic and lifestyle factors. Obesity is a major risk factor for CRC, and the mechanisms underlying this link are still unclear. However, the generalized inflammatory state of adipose tissue in obesity is thought to play a role in the association between CRC risk and development. Visceral adipose tissue (VAT) is a major source of proinflammatory cytokines and other factors that contribute to the characteristic systemic low-grade inflammation associated with obesity. VAT is also closely associated with the tumor microenvironment (TME), and recent evidence suggests that adipocytes within the TME undergo phenotypic changes that contribute to tumor progression. In this review, we aim to summarize the current evidence linking obesity and CRC, with a focus on the role of VAT in tumor etiology and progression.

MUSCLE DEPLETED OBESITY IN INDIVIDUALS SCREENED FOR COLORECTAL CÂNCER

BACKGROUND

Colorectal cancer (CRC) is the third most incident cancer in the world and the second leading cause of cancer death. Significant decreases in incidence and mortality can be achieved by reducing risk factors and adhering to healthy lifestyle recommendations, as well as screening for the disease.

OBJECTIVE

To evaluate the clinical nutritional profile of individuals at medium risk screened for CRC residing in the city of Piranhas/Alagoas.

METHODS

Cross-sectional study conducted from September to October 2020, with individuals at medium risk for CRC, of both sexes and aged between 50 and 70 years old. Participants were screened for CRC with fecal immunochemical testing (FIT) and colonoscopy. Personal, socioeconomic, clinical, lifestyle and nutritional assessment data were collected. The latter was performed using anthropometric data (weight, height, arm circumference and triceps skinfold thickness), body composition (bioimpedance) and physical examination. Descriptive analysis of data frequencies and dichotomization according to the presence or absence of overweight was performed, followed by comparison of means and medians and frequencies by chi-square or Fisher's exact test.

RESULTS

In total, 82 people agreed to undergo the clinical nutritional assessment, most of them female (56.1%; n=46), adults (56.1%; n=46), with a mean age of 59.02 years (±6.30 SD). Pre-cancerous lesions were identified in 54.5% (n=42) of those screened, 52.4% (n=43) were smokers or former smokers, and 65.9% (n=54) did not practice scheduled physical activity. Nutritional assessment showed that 64.6% (n=53) were overweight according to body mass index. On the other hand, the muscle mass, % arm muscle circumference adequacy and body muscle mass (kg) markers showed that 32.9% (n=27) and 47.6% (n=39) of the subjects were muscle depleted, respectively. Above all, overweight participants had, in parallel, lower muscle mass (P<0.05), suggesting sarcopenic obesity in this population.

CONCLUSION

Obesity is one of the main risk factors for CRC; when concomitant with sarcopenia, it favors worse health outcomes. In this context, evidence shows the need to assess muscle composition in people with obesity, especially through other methods of assessing body composition. Our results add to the evidence on the importance of the population being guided about screening and adherence to healthy lifestyle recommendations, especially strategies aimed at weight control and the practice of physical activity.

Rate and associated factors of refusal to perform immunochemical Faecal Occult Blood Test (iFOBT) among semi-urban communities

The uptake of the immunochemical faecal occult blood test (iFOBT) in many countries with an opportunistic colorectal cancer (CRC) screening programme remains suboptimal. This study aimed to determine the rate, associated factors and reasons of refusal to perform the iFOBT test offered under an opportunistic CRC screening programme in semi-urban communities. This cross-sectional study was conducted among the average-risk individuals living in semi-urban areas, who sought care from public primary care centres across Kedah state, Malaysia. The information regarding the sociodemographic and clinical characteristics of individuals who were offered the iFOBT between January and April 2019, along with their willingness to perform the test, was gathered. The factors associated with the refusal were further explored using the logistic regression analysis. The individuals offered the iFOBT (n = 920) were mainly female (52.4%) and had a mean age of 58.7±10.6 years. The refusal rate of the iFOBT was 32.2%. Patients who did not have hypertension (adjusted OR: 3.33; 95% CI: 2.44, 4.54), did not have CRC symptoms (adjusted OR: 3.15; 95% CI:1.26, 7.89), had the test offered by either medical assistants (adjusted OR: 2.44; 95% CI: 1.71, 3.49) or nurses (adjusted OR: 2.41; 95% CI 1.65, 3.51), did not have diabetes (adjusted OR: 1.99; 95% CI: 1.42, 2.77),and were not active smokers (adjusted OR: 1.74; 95% CI: 1.22, 2.47), were more likely to refuse the iFOBT. The common reasons of refusing the test included "feeling not ready for the test" (21.6%) and "feeling healthy" (14.9%). The iFOBT was refused by one-third of the average-risk individuals from semi-urban communities. The associated factors and reasons of refusal found in this study could guide policymakers in developing targeted interventions to boost the uptake of CRC screening in Malaysia.

Lipid-Based Drug Delivery Nanoplatforms for Colorectal Cancer Therapy

Colorectal cancer (CRC) is a prevalent disease worldwide, and patients at late stages of CRC often suffer from a high mortality rate after surgery. Adjuvant chemotherapeutics (ACs) have been extensively developed to improve the survival rate of such patients, but conventionally formulated ACs inevitably distribute toxic chemotherapeutic drugs to healthy organs and thus often trigger severe side effects. CRC cells may also develop drug resistance following repeat dosing of conventional ACs, limiting their effectiveness. Given these limitations, researchers have sought to use targeted drug delivery systems (DDSs), specifically the nanotechnology-based DDSs, to deliver the ACs. As lipid-based nanoplatforms have shown the potential to improve the efficacy and safety of various cytotoxic drugs (such as paclitaxel and vincristine) in the clinical treatment of gastric cancer and leukemia, the preclinical progress of lipid-based nanoplatforms has attracted increasing interest. The lipid-based nanoplatforms might be the most promising DDSs to succeed in entering a clinical trial for CRC treatment. This review will briefly examine the history of preclinical research on lipid-based nanoplatforms, summarize the current progress, and discuss the challenges and prospects of using such approaches in the treatment of CRC.

Impact of screening programme using the faecal immunochemical test on stage of colorectal cancer: Results from the IMPATTO study

To evaluate the impact of faecal immunochemical test (FIT) screening on stage distribution at diagnosis, and to estimate relative incidence rates by stage in screened at first and subsequent rounds vs. unscreened. We included all incident cases occurring in 2000-2008 in 50- to 71-year-olds residing in areas with an FIT-screening programme. Multinomial logistic models were computed to estimate the relative risk ratio (RRR) of stages I and IV, compared to stage II + III, adjusting for age, sex, geographical area, and incidence year. Proportions were then used to estimate incidence rate ratios (IRR) by stage for screened subjects at the first and at subsequent rounds vs. unscreened subjects, applying the expected changes in overall incidence during screening phases. 11,663 cancers were included: 5965 in not-invited and 5,698 in invited subjects, 3,425 of whom attendees. Compared to not-invited, invited subjects had RRR 2.04 (95% CI: 1.84; 2.46) of stage I and RRR 0.77 (95% CI: 0.69; 0.87) of stage IV. Differences were stronger comparing attendees vs. nonattendees. Interval cancers were more frequently stage I compared to non-invited (RRR 1.54; 95% CI: 1.15; 2.04), but there was no difference for stage IV. IRRs in screened at first round vs. unscreened were 4.6 (95% CI: 4.2; 5.1), 1.4 (95% CI: 1.3; 1.5) and 0.7 (95% CI: 0.6; 0.9) for stages I, II + III and IV, respectively; in the following rounds the IRRs of screened vs. unscreened were 1.4 (95% CI: 1.2; 1.6), 0.8 (95% CI: 0.7; 0.9) and 0.3 (95% CI: 0.1; 0.4) for stages I, II + III and IV, respectively. FIT screening reduces the incidence of metastatic cancers by about 70% after the first round.

Knockdown of long noncoding RNA PVT1 suppresses cell proliferation and invasion of colorectal cancer via upregulation of microRNA-214-3p

Long noncoding RNAs (lncRNAs) have been reported to be involved in the occurrence and tumorigenesis of numerous malignant cancers. Microarray expression profiles were used to screen colorectal cancer (CRC)-related differentially expressed genes and lncRNAs, which revealed that insulin receptor substrate 1 (IRS1) and lncRNA plasmacytoma variant translocation 1 (PVT1) were highly expressed in CRC. This study aimed to investigate the regulatory role of lncRNA PVT1 in CRC. Subcellular localization detected by fluorescence in situ hybridization identified that lncRNA PVT1 was primarily located in the cytoplasm. The interaction between lncRNA PVT1 and microRNA-214-3p (miR-214-3p) and IRS1 was predicted using the RNA22 website. Next the dual luciferase reporter gene assay, RNA pull-down, and RNA immunoprecipitation assays verified lncRNA PVT1 to be a competitive endogenous RNA (ceRNA) against miR-214-3p, and IRS1 was found to be a target of miR-214-3p. The expression pattern of lncRNA PVT1, miR-214-3p, IRS1, phosphoinositide 3-kinase (PI3K), and Akt was characterized in response to lncRNA PVT1 silencing or miR-214-3p upregulation. Meanwhile, their regulatory effects on cell proliferation, invasion, and apoptosis were detected in CRC cells. With increased levels of miR-214-3p and decreased levels of lncRNA PVT1 in CRC cells, the expression of phosphatidylinositol 3-kinase, putative (PI3K) and Akt was reduced, and consequently, the cell apoptosis was stimulated and cell proliferation and invasion were suppressed. All in all, lncRNA PVT1 competitively binds to miR-214-3p to upregulate the expression of IRS1 thus activating the PI3K/Akt signaling pathway, thus accelerating CRC progression. This study suggests that lncRNA PVT1 might be a potential target of therapeutic strategies for CRC treatment.NEW & NOTEWORTHY This study mainly suggests that long noncoding (lnc)RNA plasmacytoma variant translocation 1 (PVT1) is a downregulated lncRNA in colorectal cancer (CRC), accelerating CRC progression. Strikingly, lncRNA PVT1 acts as a competitive endogenous RNA against microRNA (miR)-214-3p, whereas miR-214-3p targets insulin receptor substrate 1, which draws a comprehensive picture of the potential molecular mechanisms of lncRNA PVT1 in CRC.