A Meta-Analysis of Obesity and Risk of Colorectal Cancer in Patients with Lynch Syndrome: The Impact of Sex and Genetics

Metabolic risk factors of colorectal cancer: Umbrella review

BACKGROUND AND AIM

The association between metabolic factors and colorectal cancer (CRC) risk is inconclusive. This umbrella review aimed to summarise and describe the association using existing systematic reviews and/or meta-analyses.

METHOD

Four databases (Medline, Scopus, Web of Science, and Cochrane Library) were searched for systematic reviews and/or meta-analyses of observational studies. Two independent authors extracted data on the summary estimated effect and heterogeneity of studies using I2 from the individual reviews. The Assessing the Methodological Quality of Systematic Reviews (AMSTAR 2) tool was used to evaluate the methodological quality.

RESULTS

49 articles were included in this review. Although most included studies were graded with critically low methodological quality (81.6 %), we found a significant positive association between obesity (summary relative risk (SRR) range 1.19-1.49), diabetes mellitus (SRR range 1.20-1.37), hypertension (SRR range 1.07-1.62), metabolic syndrome (SRR range 1.25-1.36), non-alcoholic fatty liver disease (pooled odds ratio (POR) range 1.13-1.56), and risk of CRC. Higher serum high-density lipoprotein cholesterol levels were associated with a lower risk of CRC in 3/6 reviews, while others did not find any association. There was no clear association between high triglyceride levels, total cholesterol levels, low-density lipoprotein cholesterol levels, and risk of CRC.

CONCLUSION

This umbrella review identified that most metabolic factors are significantly associated with increased risk of CRC. Thus, people affected by metabolic factors may be benefited from CRC screening and surveillance.

Endoscopic and Pharmacologic Treatment of Obesity in Patients With Hereditary Polyposis Syndromes

Patients with hereditary polyposis syndromes (HPS) are among the highest risk of multiple types of cancer. This risk is further magnified by comorbid obesity; however, HPS present unique risks for bariatric surgery. The advent of endoscopic bariatric and metabolic therapies along with advancements in the realm of antiobesity medications provides potential weight loss alternatives in this vulnerable population. We present 2 cases of patients with obesity and HPS successfully treated with intragastric balloons in combination with antiobesity medications.

Obesity-Associated Colorectal Cancer

Colorectal cancer (CRC) affects approximately 2 million people worldwide. Obesity is the major risk factor for CRC. In addition, obesity contributes to a chronic inflammatory stage that enhances tumor progression through the secretion of proinflammatory cytokines. In addition to an increased inflammatory response, obesity-associated cancer presents accrued molecular factors related to cancer characteristics, such as genome instability, sustained cell proliferation, telomere dysfunctions, angiogenesis, and microbial alteration, among others. Despite the evidence accumulated over the last few years, the treatments for obesity-associated CRC do not differ from the CRC treatments in normal-weight individuals. In this review, we summarize the current knowledge on obesity-associated cancer, including its epidemiology, risk factors, molecular factors, and current treatments. Finally, we enumerate possible new therapeutic targets that may improve the conditions of obese CRC patients. Obesity is key for the development of CRC, and treatments resulting in the reversal of obesity should be considered as a strategy for improving antineoplastic CRC therapies.

Modifiable risk factors for cancer among people with lynch syndrome: an international, cross-sectional survey

BACKGROUND

Lynch syndrome is the most common cause of hereditary colorectal and endometrial cancer. Lifestyle modification may provide an opportunity for adjunctive cancer prevention. In this study, we aimed to characterise modifiable risk factors in people with Lynch syndrome and compare this with international guidelines for cancer prevention.

METHODS

A cross-sectional study was carried out utilizing survey methodology. Following public and patient involvement, the survey was disseminated through patient advocacy groups and by social media. Self-reported demographic and health behaviours were collected in April 2023. Guidelines from the World Cancer Research Fund (WCRF) were used to compare percentage adherence to 9 lifestyle recommendations, including diet, physical activity, weight, and alcohol intake. Median adherence scores, as a surrogate for lifestyle risk, were calculated and compared between groups.

RESULTS

156 individuals with Lynch syndrome participated from 13 countries. The median age was 51, and 54% were cancer survivors. The mean BMI was 26.7 and the mean weekly duration of moderate to vigorous physical activity was 90 min. Median weekly consumption of ethanol was 60 g, and 3% reported current smoking. Adherence to WCRF recommendations for cancer prevention ranged from 9 to 73%, with all but one recommendation having < 50% adherence. The median adherence score was 2.5 out of 7. There was no significant association between median adherence scores and age (p = 0.27), sex (p = 0.31), or cancer history (p = 0.75).

CONCLUSIONS

We have characterised the modifiable risk profile of people living with Lynch syndrome, outlining targets for intervention based on lifestyle guidelines for the general population. As evidence supporting the relevance of modifiable factors in Lynch syndrome emerges, behavioural modification may prove an impactful means of cancer prevention.

Predicting mortality and recurrence in colorectal cancer: Comparative assessment of predictive models

Introduction

Colorectal cancer (CRC), also known as colorectal cancer, is a significant disease marked by high fatality rates, ranking as the third leading cause of global mortality. The main objective of this study was to assess the accuracy of predictive models in predicting both mortality events and the probability of disease recurrence.

Method

A retrospective analysis was conducted on a cohort of 284 individuals diagnosed with colorectal cancer between 2001 and 2017. Demographic and clinical data, including gender, disease stage, age at diagnosis, recurrence status, and treatment details, were meticulously recorded. We rigorously evaluated various predictive models, including Decision Trees, Random Forests, Random Survival Forests (RSF), Gradient Boosting, mboost, Deep Learning Neural Network (DLNN), and Cox regression. Performance metrics, such as sensitivity, positive predictive value (PPV), specificity, area under the receiver operating characteristic curve (ROC area), and overall accuracy, were calculated for each model to predict mortality and disease recurrence. The analysis was performed using R version 4.1.3 software and the Python programming language.

Results

For mortality prediction, the mboost model demonstrated the highest sensitivity at 96.9% (95% CI: 0.83-0.99) and an ROC area of 0.88. It also exhibited high specificity at 80% (95% CI: 0.59-0.93), a positive predictive value of 86.1% (95% CI: 0.70-0.95), and an overall accuracy of 89% (95% CI: 0.78-0.96). Random Forests showed perfect sensitivity of 100% (95% CI: 0.85-1) but had low specificity at 0% (95% CI: 0-0.52) and poor overall accuracy (50%). On the other hand, DLNN had the lowest performance metrics for mortality prediction, with a sensitivity of 24% (95% CI: 0.222-0.268), specificity of 75% (95% CI: 0.73-0.77), and a lower positive predictive value of 42% (95% CI: 0.38-0.45). The Gradient Boosting model showed the best performance in predicting recurrence, achieving perfect sensitivity of 100% (95% CI: 0.87-1) and high specificity at 92.9% (95% CI: 0.76-0.99). It also had a high positive predictive value of 93.3% (95% CI: 0.77-0.99). Gradient Boosting, with an ROC area of 96.4%, and mboost, with an ROC area of 75%, demonstrated remarkable performance. DLNN had the lowest performance metrics for recurrence prediction, with sensitivity at 1.75% (95% CI: 0.01-0.02), specificity at 98% (95% CI: 0.97-0.98), and a lower positive predictive value at 52.6% (95% CI: 0.39-0.65).

Conclusion

In summary, the mboost model demonstrated outstanding performance in predicting mortality, achieving exceptional results across various evaluation metrics. Random Forests exhibited perfect sensitivity but showed poor specificity and overall accuracy. The DLNN model displayed the lowest performance metrics for mortality prediction. In terms of recurrence prediction, the Gradient Boosting model outperformed other models with perfect sensitivity, high specificity, and positive predictive value. The DLNN model had the lowest performance metrics for recurrence prediction. Overall, the results emphasize the effectiveness of the mboost and Gradient Boosting models in predicting mortality and recurrence in colorectal cancer patients.

Modifiable Risk Factors and Risk of Colorectal and Endometrial Cancers in Lynch Syndrome: A Systematic Review and Meta-Analysis

PURPOSE

Lynch syndrome is the most common hereditary cause of colorectal and endometrial cancers. Modifiable risk factors, including obesity, physical activity, alcohol intake, and smoking, are well-established in sporadic cancers but are less studied in Lynch syndrome.

METHODS

Searches were conducted on MEDLINE, Embase, and Web of Science for cohort studies that investigated the association between modifiable risk factors and the risk of colorectal or endometrial cancer in people with Lynch syndrome. Adjusted hazard ratios (HRs) and 95% CIs for colorectal and endometrial cancers were pooled using a random effects model. The protocol was prospectively registered on PROSPERO (CRD 42022378462), and the meta-analysis was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses and Meta-Analysis of Observational Studies in Epidemiology reporting guidelines.

RESULTS

A total of 770 citations were reviewed. Eighteen studies were identified for qualitative synthesis, with seven colorectal cancer (CRC) studies eligible for meta-analysis. Obesity (HR, 2.38 [95% CI, 1.52 to 3.73]) was associated with increased CRC risk. There was no increased CRC risk associated with smoking (HR, 1.04 [95% CI, 0.82 to 1.32]) or alcohol intake (HR, 1.32 [95% CI, 0.97 to 1.81]). Type 2 diabetes mellitus (T2DM) and some dietary factors might increase risk of CRC although more studies are needed. In a qualitative synthesis of three endometrial cancer cohort studies, female hormonal risk factors and T2DM may affect the risk of endometrial cancer, but obesity was not associated with an increased risk.

CONCLUSION

Lifestyle recommendations related to weight and physical activity may also be relevant to cancer prevention for individuals with Lynch syndrome. Further high-quality prospective cohort studies, in particular, including endometrial cancer as an end point, are needed to inform evidence-based cancer prevention strategies in this high-risk population.

Obesity, obesities and gastrointestinal cancers

Obesity has been recognized to be increasing globally and is designated a disease with adverse consequences requiring early detection and appropriate care. In addition to being related to metabolic syndrome disorders such as type 2 diabetes, hypertension, stroke, and premature coronary artery disease. Obesity is also etiologically linked to several cancers. The non-gastrointestinal cancers are breast, uterus, kidneys, ovaries, thyroid, meningioma, and thyroid. Gastrointestinal (GI) cancers are adenocarcinoma of the esophagus, liver, pancreas, gallbladder, and colorectal. The brighter side of the problem is that being overweight and obese and cigarette smoking are mostly preventable causes of cancers. Epidemiology and clinical studies have revealed that obesity is heterogeneous in clinical manifestations. In clinical practice, BMI is calculated by dividing a person's weight in kilograms by the square of the person's height in square meters (kg/m2). A BMI above 30 kg/m2 (defining obesity in many guidelines) is considered obesity. However, obesity is heterogeneous. There are subdivisions for obesity, and not all obesities are equally pathogenic. Adipose tissue, in particular, visceral adipose tissue (VAT), is endocrine and abdominal obesity (a surrogate for VAT) is evaluated by waist-hip measurements or just waist measures. Visceral Obesity, through several hormonal mechanisms, induces a low-grade chronic inflammatory state, insulin resistance, components of metabolic syndrome, and cancers. Metabolically obese, normal-weight (MONW) individuals in several Asian countries may have BMI below normal levels to diagnose obesity but suffer from many obesity-related complications. Conversely, some people have high BMI but are generally healthy with no features of metabolic syndrome. Many clinicians advise weight loss by dieting and exercise to metabolically healthy obese with large body habitus than to individuals with metabolic obesity but normal BMI. The GI cancers (esophagus, pancreas, gallbladder, liver, and colorectal) are individually discussed, emphasizing the incidence, possible pathogenesis, and preventive measures. From 2005 to 2014, most cancers associated with overweight and Obesity increased in the United States, while cancers related to other factors decreased. The standard recommendation is to offer or refer adults with a body mass index (BMI) of 30 or more to intensive, multicomponent behavioral interventions. However, the clinicians have to go beyond. They should critically evaluate BMI with due consideration for ethnicity, body habitus, and other factors that influence the type of obesity and obesity-related risks. In 2001, the Surgeon General's ``Call to Action to Prevent and Decrease Overweight and Obesity'' identified obesity as a critical public health priority for the United States. At government levels reducing obesity requires policy changes that improve the food and physical activity for all. However, implementing some policies with the most significant potential benefit to public health is politically tricky. The primary care physician, as well as subspecialists, should identify overweight and Obesity based on all the variable factors in the diagnosis. The medical community should address the prevention of overweight and Obesity as an essential part of medical care as much as vaccination in preventing infectious diseases at all levels- from childhood, to adolescence, and adults.

Protective Effects of Long-Term Usage of Cyclo-Oxygenase-2 Inhibitors on Colorectal Cancer in Genetically Predisposed Individuals and Their Overall Effect on Prognosis: A Systematic Review

Colorectal cancer (CRC) is a major global health concern, accounting for significant cancer-related morbidity and mortality worldwide. Despite advancements in early detection and treatment modalities, the prevention of CRC remains a critical goal. Cyclo-oxygenase-2 (COX-2) is an inducible enzyme involved in the production of pro-inflammatory prostaglandins, which play a crucial role in various cellular processes, including inflammation, cell proliferation, apoptosis, and angiogenesis. Elevated COX-2 expression has been consistently observed in colorectal tumors, indicating their role in the pathogenesis of cancer. COX-2 inhibitors, such as celecoxib and rofecoxib, have been studied as potentially effective treatment modalities due to their ability to decrease prostaglandin levels, which are generally higher in cancer patients. Aberrant prostaglandin production is linked to the adenoma-carcinoma sequence, during which adenomas turn dysplastic and accumulate enough damage to become malignant. COX-2 inhibitors have also been shown to modulate various signaling pathways involved in CRC development, such as wingless-related integration site/β-catenin (Wnt/β-catenin), mitogen-activated protein kinase (MAPK), and phosphoinositide-3-kinase-protein kinase B/Akt (PI3K/Akt) pathways. This systematic review aimed to evaluate the protective effects of long-term usage of COX-2 inhibitors on CRC in genetically predisposed individuals and their overall effect on the prognosis of the disease. The researchers conducted a systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines and collected data from several databases, including PubMed, PubMed Central, Cochrane Library, and Web of Science. The search strategy combined keywords related to CRC, COX-2 inhibitors, protective effects, and prognosis. They identified 1189 articles and shortlisted 26 full-text articles that met the eligibility criteria. Quality assessment tools, such as the Assessment of Multiple Systematic Review (AMSTAR) for systematic reviews, the Cochrane bias assessment tool for randomized control trials, the scale for the assessment of narrative review articles (SANRA) checklist for narrative reviews, and the Joanna Briggs Institute (JBI) tool for cross-sectional studies and case reports, are used. This review's conclusions will assist in determining the effectiveness of COX-2 inhibitors to prevent CRC. This review may also contribute to developing guidelines for clinicians to manage genetically predisposed individuals with CRC. Furthermore, the results of this review will shed light on the potential of COX-2 inhibitors as a preventive measure against CRC in genetically predisposed individuals.

Determinants of adherence to recommendations on physical activity, red and processed meat intake, and body weight among lynch syndrome patients

This study aimed to identify determinants of adherence to lifestyle and body weight recommendations for cancer prevention among Lynch Syndrome (LS) patients. Cross-sectional baseline data of LS patients participating in the Lifestyle & Lynch (LiLy) study was used to assess determinants of adherence to the World Cancer Research Fund cancer prevention recommendations on body weight, physical activity, and red and processed meat intake. Adherence and potential determinants of adherence were assessed using questionnaires. Multivariable logistic regression analyses were conducted to identify determinants of adherence. Of the 211 participants, 50.2% adhered to the body weight recommendation, 78.7% adhered to the physical activity recommendation, and 33.6% adhered to the red and processed meat recommendation. Being younger and having a higher level of education were associated with adherence to the recommendation on body weight. Having knowledge about the recommendation was associated with adherence to the recommendations on physical activity and red and processed meat. Results confirm that knowledge about recommendations for cancer prevention is an important determinant for adherence and suggest that strategies to increase knowledge should be included in lifestyle promotion targeted at LS patients, along with behavior change techniques influencing other modifiable determinants.

Body mass index and molecular subtypes of colorectal cancer

BACKGROUND

Obesity is an established risk factor for colorectal cancer (CRC), but the evidence for the association is inconsistent across molecular subtypes of the disease.

METHODS

We pooled data on body mass index (BMI), tumor microsatellite instability status, CpG island methylator phenotype status, BRAF and KRAS mutations, and Jass classification types for 11 872 CRC cases and 11 013 controls from 11 observational studies. We used multinomial logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI) adjusted for covariables.

RESULTS

Higher BMI was associated with increased CRC risk (OR per 5 kg/m2 = 1.18, 95% CI = 1.15 to 1.22). The positive association was stronger for men than women but similar across tumor subtypes defined by individual molecular markers. In analyses by Jass type, higher BMI was associated with elevated CRC risk for types 1-4 cases but not for type 5 CRC cases (considered familial-like/Lynch syndrome microsatellite instability-H, CpG island methylator phenotype-low or negative, BRAF-wild type, KRAS-wild type, OR = 1.04, 95% CI = 0.90 to 1.20). This pattern of associations for BMI and Jass types was consistent by sex and design of contributing studies (cohort or case-control).

CONCLUSIONS

In contrast to previous reports with fewer study participants, we found limited evidence of heterogeneity for the association between BMI and CRC risk according to molecular subtype, suggesting that obesity influences nearly all major pathways involved in colorectal carcinogenesis. The null association observed for the Jass type 5 suggests that BMI is not a risk factor for the development of CRC for individuals with Lynch syndrome.

Obesity and Cancer: A Current Overview of Epidemiology, Pathogenesis, Outcomes, and Management

BACKGROUND

Obesity or excess body fat is a major global health challenge that has not only been associated with diabetes mellitus and cardiovascular disease but is also a major risk factor for the development of and mortality related to a subgroup of cancer. This review focuses on epidemiology, the relationship between obesity and the risk associated with the development and recurrence of cancer and the management of obesity.

METHODS

A literature search using PubMed and Google Scholar was performed and the keywords 'obesity' and cancer' were used. The search was limited to research papers published in English prior to September 2022 and focused on studies that investigated epidemiology, the pathogenesis of cancer, cancer incidence and the risk of recurrence, and the management of obesity.

RESULTS

About 4-8% of all cancers are attributed to obesity. Obesity is a risk factor for several major cancers, including post-menopausal breast, colorectal, endometrial, kidney, esophageal, pancreatic, liver, and gallbladder cancer. Excess body fat results in an approximately 17% increased risk of cancer-specific mortality. The relationship between obesity and the risk associated with the development of cancer and its recurrence is not fully understood and involves altered fatty acid metabolism, extracellular matrix remodeling, the secretion of adipokines and anabolic and sex hormones, immune dysregulation, and chronic inflammation. Obesity may also increase treatment-related adverse effects and influence treatment decisions regarding specific types of cancer therapy. Structured exercise in combination with dietary support and behavior therapy are effective interventions. Treatment with glucagon-like peptide-1 analogues and bariatric surgery result in more rapid weight loss and can be considered in selected cancer survivors.

CONCLUSIONS

Obesity increases cancer risk and mortality. Weight-reducing strategies in obesity-associated cancers are important interventions as a key component of cancer care. Future studies are warranted to further elucidate the complex relationship between obesity and cancer with the identification of targets for effective interventions.

Endoscopic surveillance of Lynch syndrome at a highly specialized center in Sweden: An observational study of interval colorectal cancer and individual risk factors

Introduction

Lynch syndrome (LS) is the most common hereditary cause of colorectal cancer (CRC). In order to detect CRCs amongst LS patients, regular colonoscopies are recommended. However, an international agreement on an optimal surveillance interval has not yet been reached. In addition, few studies have investigated factors that could potentially increase the CRC risk amongst LS patients.

Aims

The primary aim was to describe the frequency of CRCs detected during endoscopic surveillance and to estimate the interval from a clean colonoscopy to CRC detection amongst LS patients. The secondary aim was to investigate individual risk factors, including sex, LS genotype, smoking, aspirin use and body mass index (BMI), on CRC risk amongst patients that develop CRC before and during surveillance.

Material and methods

Clinical data and colonoscopy findings from 366 LS patients' 1437 surveillance colonoscopies were collected from medical records and patient protocols. Logistic regression and Fisher's exact test were used to investigate associations between individual risk factors and CRC development. Mann-Whitney U test was used to compare the distribution of TNM stages of CRC detected before surveillance and after index.

Results

CRC was detected in 80 patients before surveillance and in 28 patients during surveillance (10 at index and 18 after index). During the surveillance programme, CRC was detected within 24 months in 65% of the patients, and after 24 months within 35% of the patients. CRC was more common amongst men, previous and current smokers, and the odds of developing CRC also increased with an increasing BMI. CRCs were more often detected amongst MLH1 and MSH2 carriers during surveillance, compared to the other genotypes.

Conclusions

We found that 35% of the CRC cases detected during surveillance were found after 24 months. MLH1 and MSH2 carriers were at higher risk of developing CRC during surveillance. Additionally, men, current or previous smokers, and patients with a higher BMI were at higher risk of developing CRC. Currently, LS patients are recommended a "one-size-fits-all" surveillance program. The results support the development of a risk-score whereby individual risk factors should be taken into consideration when deciding on an optimal surveillance interval.

Lifestyle Behavior Interventions for Preventing Cancer in Adults with Inherited Cancer Syndromes: Systematic Review

(1) Background: The link between lifestyle behaviors and cancer risk is well established, which is important for people with personal/family history or genetic susceptibility. Genetic testing is not sufficient motivation to prompt healthier lifestyle behaviors. This systematic review aims to describe and assess interventions for promoting healthy behaviors in people at high risk of cancer. (2) Methods: The review was performed according to PRISMA guidelines using search terms related to hereditary cancer and health education to identify studies indexed in: CINAHL, MEDLINE, PubMed, Cochrane Library, Scopus, and Joanna Briggs, and published from January 2010 to July 2022. (3) Results: The search yielded 1558 initial records; four randomized controlled trials were eligible. Three included patients with and without a personal history of cancer who were at increased risk of cancer due to inherited cancer syndromes, and one included people undergoing genetic testing due to family history. Interventions targeted diet, physical activity, and alcohol. (4) Conclusions: There is a paucity of research on interventions for promoting healthy lifestyle behaviors in people with a high risk of cancer. Interventions produced positive short-term results, but there was no evidence that behavioral modifications were sustained over time. All healthcare professionals can actively promote healthy behaviors that may prevent cancer.

Metabolic syndrome, obesity and cancer risk

PURPOSE OF REVIEW

This review aims to report the latest discoveries regarding the relationship between BMI, obesity, and cancer development and treatment.

RECENT FINDINGS

Obesity and metabolic syndrome relationships with cancer have been deeply investigated in the literature but their association is still debated. Currently, it has been recorded an association between BMI and endometrial, colorectal, gastric, liver, bladder, and prostate cancer. The mechanisms behind this association have also been investigated. It has been hypothesized that chronic inflammation determined by obesity may concur to the development of tumors and that Insulin Resistance may enhance cell proliferation directly or indirectly. Moreover, different studies suggest that the relationship between higher BMI and cancer may include metabolic disturbances comparable to those linked to metabolic syndrome. However, greater weight has been linked to a better overall prognosis in patients with advanced disease, a concept called the obesity paradox. This paradox has been recently investigated in the context of urological malignancies, such as bladder, prostate, and kidney cancer.

SUMMARY

Patients' metabolic and morphological status may impact their risk of developing different types of tumors and the response to systemic therapy. However, further research is necessary to better delineate the mechanisms behind these associations and how they could or should affect medical decision.