Body mass index in early adulthood and colorectal cancer risk for carriers and non-carriers of germline mutations in DNA mismatch repair genes

Adiposity and risks of gastrointestinal cancers: A 10-year prospective study of 0.5 million Chinese adults

Associations of adiposity with risks of oesophageal squamous cell carcinoma (ESCC) and non-cardia stomach cancer, both prevalent in China, are still inconclusive. While adiposity is an established risk factor for colorectal cancer, the relevance of fat-free mass and early-adulthood adiposity remains to be explored. The prospective China Kadoorie Biobank study included 0.5 million adults (aged 30-79 years) from 10 areas in China. Participants' body size and composition were measured at baseline and at resurveys (amongst a subset). After >10 years of follow-up, 2350, 3345 and 3059 incident cases of oesophageal (EC), stomach (SC) and colorectal (CRC) cancers were recorded, respectively. Cox regression was used to estimate hazard ratios (HRs) for these cancers in relation to different adiposity traits. General and central adiposity were inversely associated with EC (primarily ESCC) risk, with HRs of 0.81 (95% CI 0.77-0.85), 0.76 (0.72-0.81) and 0.87 (0.83-0.92) per SD increase in usual levels of BMI, body fat percentage (BF%) and waist circumference (WC), respectively. Adiposity was also inversely associated with SC risk [HR = 0.79 (0.75-0.83) and 0.88 (0.84-0.92) per SD increase in usual BF% and WC], with heterogeneity by cardia and non-cardia subsites, and positively associated with CRC [HR = 1.09 (1.03-1.15) and 1.17 (1.12-1.22) per SD higher usual BF% and WC]. Fat-free mass was inversely associated with EC [HR = 0.93 (0.89-0.98) per SD increase] but positively associated with CRC [1.09 (1.04-1.14)], while BMI at age 25 was positively associated with all three cancers. After mutual adjustment, general adiposity remained inversely associated with EC and SC, while central adiposity remained positively associated with CRC.

The Influence of Diet and Obesity in Lynch Syndrome: What Do We Know So Far

Of all new cases of colorectal cancer, Lynch syndrome (LS) accounts for approximately 3%. This syndrome is the most common hereditary cancer syndrome and is caused by pathogenic variants in the genes responsible for DNA mismatch repair. Although the relationship between colorectal cancer risk and diet is well established, little is known regarding the influence of diet and nutritional characteristics on LS's clinical evolution. There is some evidence suggesting that individuals living with LS should follow general guidelines for diet and alcohol restriction/moderation, so as to achieve and maintain a favorable weight status and overall health and quality of life. However, more research is needed, preferentially from clinical studies of a prospective nature with robust designs, to better inform diet and behavioral patterns targeting cancer prevention in LS.

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.

Association of High Body Mass Index in Early Life With the Development of Colorectal Cancer

SIGNIFICANCE

This study on the relationship between early life high BMI and the development of CRC reveals the role of high BMI during childhood and adolescence in the occurrence and progression of CRC. It suggests the importance of restoring normal weight or reducing weight in individuals with high BMI early in life for the prevention of colorectal cancer.

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.

Dietary behaviours of individuals with lynch syndrome at high risk of colorectal cancer: Results from the AAS-lynch study

BACKGROUND & AIMS

Individuals with Lynch syndrome (LS) have a high lifetime risk of developing colorectal cancer (CRC) due to genetic alterations. Nutrition is one of the main modifiable risk factors for sporadic CRC, however this has not been established in LS patients. The present study aimed to give a detailed overview of dietary intakes in individuals with LS, and associated individual characteristics.

METHODS

Dietary behaviours of individuals with LS from the AAS-Lynch clinical trial (2017-2022) were obtained using a food frequency questionnaire. Dietary intakes, food group consumption and overall diet quality (dietary patterns, adherence to the Mediterranean diet) were described according to sociodemographic, anthropometric and clinical characteristics, and compared to participants without LS from the NutriNet-Santé study (matched on sex, age, BMI and region).

RESULTS

280 individuals with LS were included in this analysis and matched with 547 controls. Compared to controls, LS patients consumed less fibre, legumes, fruit and vegetables and more red and processed meat (all p < 0.01). They also had a lower Mediterranean diet score (p = 0.002). Among LS patients, men, younger patients, or those with disadvantaged situation had a diet of poorer nutritional quality with lower adherence to a "Healthy" diet (all p ≤ 0.01). LS Patients with prevalent CRC had a higher consumption of dairy products than recommended, while those with prevalent adenoma consumed more vegetables, and less sugar and sweets (all p ≤ 0.01).

CONCLUSIONS

Although patients with LS were aware of their high lifetime risk of developing cancer, their diets were not optimal and included nutritional risk factors associated to CRC.

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.

Lynch syndrome: from detection to treatment

Lynch syndrome (LS) is an inherited cancer predisposition syndrome associated with high lifetime risk of developing tumours, most notably colorectal and endometrial. It arises in the context of pathogenic germline variants in one of the mismatch repair genes, that are necessary to maintain genomic stability. LS remains underdiagnosed in the population despite national recommendations for empirical testing in all new colorectal and endometrial cancer cases. There are now well-established colorectal cancer surveillance programmes, but the high rate of interval cancers identified, coupled with a paucity of high-quality evidence for extra-colonic cancer surveillance, means there is still much that can be achieved in diagnosis, risk-stratification and management. The widespread adoption of preventative pharmacological measures is on the horizon and there are exciting advances in the role of immunotherapy and anti-cancer vaccines for treatment of these highly immunogenic LS-associated tumours. In this review, we explore the current landscape and future perspectives for the identification, risk stratification and optimised management of LS with a focus on the gastrointestinal system. We highlight the current guidelines on diagnosis, surveillance, prevention and treatment and link molecular disease mechanisms to clinical practice recommendations.

Is early-onset cancer an emerging global epidemic? Current evidence and future implications

Over the past several decades, the incidence of early-onset cancers, often defined as cancers diagnosed in adults <50 years of age, in the breast, colorectum, endometrium, oesophagus, extrahepatic bile duct, gallbladder, head and neck, kidney, liver, bone marrow, pancreas, prostate, stomach and thyroid has increased in multiple countries. Increased use of screening programmes has contributed to this phenomenon to a certain extent, although a genuine increase in the incidence of early-onset forms of several cancer types also seems to have emerged. Evidence suggests an aetiological role of risk factor exposures in early life and young adulthood. Since the mid-20th century, substantial multigenerational changes in the exposome have occurred (including changes in diet, lifestyle, obesity, environment and the microbiome, all of which might interact with genomic and/or genetic susceptibilities). However, the effects of individual exposures remain largely unknown. To study early-life exposures and their implications for multiple cancer types will require prospective cohort studies with dedicated biobanking and data collection technologies. Raising awareness among both the public and health-care professionals will also be critical. In this Review, we describe changes in the incidence of early-onset cancers globally and suggest measures that are likely to reduce the burden of cancers and other chronic non-communicable diseases.

Colorectal cancer incidences in Lynch syndrome: a comparison of results from the prospective lynch syndrome database and the international mismatch repair consortium

OBJECTIVE

To compare colorectal cancer (CRC) incidences in carriers of pathogenic variants of the MMR genes in the PLSD and IMRC cohorts, of which only the former included mandatory colonoscopy surveillance for all participants.

METHODS

CRC incidences were calculated in an intervention group comprising a cohort of confirmed carriers of pathogenic or likely pathogenic variants in mismatch repair genes (path_MMR) followed prospectively by the Prospective Lynch Syndrome Database (PLSD). All had colonoscopy surveillance, with polypectomy when polyps were identified. Comparison was made with a retrospective cohort reported by the International Mismatch Repair Consortium (IMRC). This comprised confirmed and inferred path_MMR carriers who were first- or second-degree relatives of Lynch syndrome probands.

RESULTS

In the PLSD, 8,153 subjects had follow-up colonoscopy surveillance for a total of 67,604 years and 578 carriers had CRC diagnosed. Average cumulative incidences of CRC in path_MLH1 carriers at 70 years of age were 52% in males and 41% in females; for path_MSH2 50% and 39%; for path_MSH6 13% and 17% and for path_PMS2 11% and 8%. In contrast, in the IMRC cohort, corresponding cumulative incidences were 40% and 27%; 34% and 23%; 16% and 8% and 7% and 6%. Comparing just the European carriers in the two series gave similar findings. Numbers in the PLSD series did not allow comparisons of carriers from other continents separately. Cumulative incidences at 25 years were < 1% in all retrospective groups.

CONCLUSIONS

Prospectively observed CRC incidences (PLSD) in path_MLH1 and path_MSH2 carriers undergoing colonoscopy surveillance and polypectomy were higher than in the retrospective (IMRC) series, and were not reduced in path_MSH6 carriers. These findings were the opposite to those expected. CRC point incidence before 50 years of age was reduced in path_PMS2 carriers subjected to colonoscopy, but not significantly so.

European guidelines from the EHTG and ESCP for Lynch syndrome: an updated third edition of the Mallorca guidelines based on gene and gender

BACKGROUND

Lynch syndrome is the most common genetic predisposition for hereditary cancer but remains underdiagnosed. Large prospective observational studies have recently increased understanding of the effectiveness of colonoscopic surveillance and the heterogeneity of cancer risk between genotypes. The need for gene- and gender-specific guidelines has been acknowledged.

METHODS

The European Hereditary Tumour Group (EHTG) and European Society of Coloproctology (ESCP) developed a multidisciplinary working group consisting of surgeons, clinical and molecular geneticists, pathologists, epidemiologists, gastroenterologists, and patient representation to conduct a graded evidence review. The previous Mallorca guideline format was used to revise the clinical guidance. Consensus for the guidance statements was acquired by three Delphi voting rounds.

RESULTS

Recommendations for clinical and molecular identification of Lynch syndrome, surgical and endoscopic management of Lynch syndrome-associated colorectal cancer, and preventive measures for cancer were produced. The emphasis was on surgical and gastroenterological aspects of the cancer spectrum. Manchester consensus guidelines for gynaecological management were endorsed. Executive and layperson summaries were provided.

CONCLUSION

The recommendations from the EHTG and ESCP for identification of patients with Lynch syndrome, colorectal surveillance, surgical management of colorectal cancer, lifestyle and chemoprevention in Lynch syndrome that reached a consensus (at least 80 per cent) are presented.

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

There appears to be a sex-specific association between obesity and colorectal neoplasia in patients with Lynch Syndrome (LS). We meta-analyzed studies reporting on obesity and colorectal cancer (CRC) risk in LS patients to test whether obese subjects were at increased risk of cancer compared to those of normal weight. We explored also a possible sex-specific relationship between adiposity and CRC risk among patients with LS. The summary relative risk (SRR) and 95% confidence intervals (CI) were calculated through random effect models. We investigated the causes of between-study heterogeneity and assessed the presence of publication bias. We were able to retrieve suitable data from four independent studies. We found a twofold risk of CRC in obese men compared to nonobese men (SRR = 2.09; 95%CI: 1.23–3.55, I² = 33%), and no indication of publication bias (p = 0.13). No significantly increased risk due to obesity was found for women. A 49% increased CRC risk for obesity was found for subjects with an MLH1 mutation (SRR = 1.49; 95%CI: 1.11–1.99, I² = 0%). These results confirm the different effects of sex on obesity and CRC risk and also support the public measures to reduce overweight in people with LS, particularly for men.

Early age onset colorectal cancer

The incidence and mortality associated with colorectal cancer (CRC) diagnosed in patients under the age of 50 have been steadily increasing. The exact etiology of these epidemiologic trends is unclear. This chapter will provide a comprehensive review on the topic of early age onset colorectal cancer (EAO-CRC), defined as colorectal cancer (CRC) diagnosed in patients under the age of 50. Topics reviewed will include the epidemiology of EAO-CRC around the world, clinical and pathological features of EAO-CRC in contrast to later age onset CRC (CRC diagnosed on those over the age of 50) and the observed molecular and somatic characteristics. This chapter will review the etiologies to EAO-CRC and the established, as well as proposed risk factors for disease. Evidence-based approaches to prevention, early detection, treatment and survivorship will be presented.

Body Weight, Physical Activity, and Risk of Cancer in Lynch Syndrome

Lynch syndrome (LS) increases cancer risk. There is considerable individual variation in LS cancer occurrence, which may be moderated by lifestyle factors, such as body weight and physical activity (PA). The potential associations of lifestyle and cancer risk in LS are understudied. We conducted a retrospective study with cancer register data to investigate associations between body weight, PA, and cancer risk among Finnish LS carriers. The participants (n = 465, 54% women) self-reported their adulthood body weight and PA at 10-year intervals. Overall cancer risk and colorectal cancer (CRC) risk was analyzed separately for men and women with respect to longitudinal and near-term changes in body weight and PA using extended Cox regression models. The longitudinal weight change was associated with an increased risk of all cancers (HR 1.02, 95% CI 1.00-1.04) and CRC (HR 1.03, 1.01-1.05) in men. The near-term weight change was associated with a lower CRC risk in women (HR 0.96, 0.92-0.99). Furthermore, 77.6% of the participants retained their PA category over time. Men in the high-activity group had a reduced longitudinal cancer risk of 63% (HR 0.37, 0.15-0.98) compared to men in the low-activity group. PA in adulthood was not associated with cancer risk among women. These results emphasize the role of weight maintenance and high-intensity PA throughout the lifespan in cancer prevention, particularly in men with LS.

Is a colorectal neoplasm diagnosis a trigger to change dietary and other lifestyle habits for persons with Lynch syndrome? A prospective cohort study

A cancer diagnosis is suggested to be associated with changes in dietary and lifestyle habits. Whether this applies to persons with familial cancer, such as Lynch syndrome (LS) is unknown. We investigated whether a colorectal neoplasm (CRN) diagnosis in persons with LS is associated with changes in dietary and lifestyle habits over time. We used data of confirmed LS mutation carriers from the GEOLynch study, a prospective cohort study. Information on dietary intake and lifestyle habits was collected with a validated semi-quantitative food frequency questionnaire and a general questionnaire administered at baseline (2006-2008) and follow-up (2012-2017). Participants' medical records were used to identify CRN diagnoses. Changes in dietary and lifestyle habits in the CRN and the no-CRN group were compared using multivariable linear regression models for continuous variables and cross-tables with percentage change at follow-up compared with baseline for categorical variables. Of the 324 included participants, 146 developed a CRN (CRN group) between baseline and follow-up, while 178 did not (no-CRN group). Smoking cessation was more often reported in the CRN than in the no-CRN group (41.4% vs. 35.0%). There were no differences in changes of energy intake, alcohol, red meat, processed meat, dairy, fruit, vegetables and dietary fiber consumption, BMI, physical activity and NSAID use. Apart from a potentially higher likelihood of smoking cessation, we found little evidence that a CRN diagnosis is associated with changes in lifestyle habits in persons with LS.

Excessive Body Fat at a Young Age Increases the Risk of Colorectal Cancer: A Systematic Review and Meta-Analysis

Overweight and obesity was considered as a risk factor for colorectal cancer (CRC), and CRC development may be due to exposure during one's youth. Metabolic syndrome and insulin resistance seem to play an important role in the underlying mechanisms. Even though several studies indicated the association between BMI at young age and CRC risks, an identified founding is still lacked. Therefore, we conducted a meta-analysis and a dose-response analysis to quantify the association between BMI at young age and CRC risks with relative accuracy. We searched the PubMed, Embase, Medline and Cochrane Library databases for articles published before Sep. 15, 2019. Fifteen articles with 2 520 091 participants were included. Risk for CRC was estimated using relative risks (RR) and 95% confidence intervals (CIs). Compared with individuals with normal weight, overweight and obese young adults had a significantly higher risk of CRC (relative risks (RR):18%, 95% CI:1.08, 1.28； RR:32%, 95% CI: 1.11, 1.56, respectively). However, this correlation may not exist for obese women (RR: 1.22, 95% CI: 0.99, 1.51); Overweight may not a risk factor for rectal cancer (RC) (RR: 1.12, 95% CI: 0.97, 1.29). In the dose-response analysis, we observed a linear relationship between BMI at a young age and CRC risk, with each 1 kg/m² increment associated with a 2% increased risk. Higher BMI at a young age was positively associated with CRC risk, which indicates that weight control since a young age was needed.

Penetrance of Colorectal Cancer Among Mismatch Repair Gene Mutation Carriers: A Meta-Analysis

BACKGROUND

Lynch syndrome, the most common colorectal cancer (CRC) syndrome, is caused by germline mismatch repair (MMR) genes. Precise estimates of age-specific risks are crucial for sound counseling of individuals managing a genetic predisposition to cancer, but published risk estimates vary. The objective of this work is to provide gene-, sex-, and age-specific risk estimates of CRC for MMR mutation carriers that comprehensively reflect the best available data.

METHODS

We conducted a meta-analysis to combine risk information from multiple studies on Lynch syndrome-associated CRC. We used a likelihood-based approach to integrate reported measures of CRC risk and deconvolved aggregated information to estimate gene- and sex-specific risk.

RESULTS

Our comprehensive search identified 10 studies (8 on MLH1, 9 on MSH2, and 3 on MSH6). We estimated the cumulative risk of CRC by age and sex in heterozygous mutation carriers. At age 70 years, for male and female carriers, respectively, risks for MLH1 were 43.9% (95% confidence interval [CI] = 39.6% to 46.6%) and 37.3% (95% CI = 32.2% to 40.2%), for MSH2 were 53.9% (95% CI = 49.0% to 56.3%) and 38.6% (95% CI = 34.1% to 42.0%), and for MSH6 were 12.0% (95% CI = 2.4% to 24.6%) and 12.3% (95% CI = 3.5% to 23.2%).

CONCLUSIONS

Our results provide up-to-date and comprehensive age-specific CRC risk estimates for counseling and risk prediction tools. These will have a direct clinical impact by improving prevention and management strategies for both individuals who are MMR mutation carriers and those considering testing.

Molecular pathology of Lynch syndrome

Lynch syndrome (LS) is characterised by predisposition to colorectal, endometrial, and other cancers and is caused by inherited pathogenic variants affecting the DNA mismatch repair (MMR) genes MLH1, MSH2, MSH6, and PMS2. It is probably the most common predisposition to cancer, having an estimated prevalence of between 1/100 and 1/180. Resources such as the International Society for Gastrointestinal Hereditary Cancer's MMR gene variant database, the Prospective Lynch Syndrome Database (PLSD), and the Colon Cancer Family Register (CCFR), as well as pathological and immunological studies, are enabling advances in the understanding of LS. These include defined criteria by which to interpret gene variants, the function of MMR in the normal control of apoptosis, definition of the risks of the various cancers, and the mechanisms and pathways by which the colorectal and endometrial tumours develop, including the critical role of the immune system. Colorectal cancers in LS can develop along three pathways, including flat intramucosal lesions, which depend on the underlying affected MMR gene. This gives insights into the limitations of colonoscopic surveillance and highlights the need for other forms of anti-cancer prophylaxis in LS. Finally, it shows that the processes of autoimmunisation and immunoediting fundamentally constrain the development of tumours in LS and explain the efficacy of immune checkpoint blockade therapy in MMR-deficient tumours. © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Guidelines for the management of hereditary colorectal cancer from the British Society of Gastroenterology (BSG)/Association of Coloproctology of Great Britain and Ireland (ACPGBI)/United Kingdom Cancer Genetics Group (UKCGG)

Heritable factors account for approximately 35% of colorectal cancer (CRC) risk, and almost 30% of the population in the UK have a family history of CRC. The quantification of an individual's lifetime risk of gastrointestinal cancer may incorporate clinical and molecular data, and depends on accurate phenotypic assessment and genetic diagnosis. In turn this may facilitate targeted risk-reducing interventions, including endoscopic surveillance, preventative surgery and chemoprophylaxis, which provide opportunities for cancer prevention. This guideline is an update from the 2010 British Society of Gastroenterology/Association of Coloproctology of Great Britain and Ireland (BSG/ACPGBI) guidelines for colorectal screening and surveillance in moderate and high-risk groups; however, this guideline is concerned specifically with people who have increased lifetime risk of CRC due to hereditary factors, including those with Lynch syndrome, polyposis or a family history of CRC. On this occasion we invited the UK Cancer Genetics Group (UKCGG), a subgroup within the British Society of Genetic Medicine (BSGM), as a partner to BSG and ACPGBI in the multidisciplinary guideline development process. We also invited external review through the Delphi process by members of the public as well as the steering committees of the European Hereditary Tumour Group (EHTG) and the European Society of Gastrointestinal Endoscopy (ESGE). A systematic review of 10 189 publications was undertaken to develop 67 evidence and expert opinion-based recommendations for the management of hereditary CRC risk. Ten research recommendations are also prioritised to inform clinical management of people at hereditary CRC risk.

Type 2 diabetes mellitus, blood cholesterol, triglyceride and colorectal cancer risk in Lynch syndrome

Background

Type 2 diabetes mellitus and high total cholesterol and triglycerides are known to be associated with increased colorectal cancer risk for the general population. These associations are unknown for people with a germline DNA mismatch repair gene mutation (Lynch syndrome), who are at high risk of colorectal cancer.

Methods

This study included 2023 (56.4% female) carriers with a mismatch repair gene mutation (737 in MLH1, 928 in MSH2, 230 in MSH6, 106 in PMS2, 22 in EPCAM) recruited by the Colon Cancer Family Registry between 1998 and 2012. Weighted Cox regression was used to estimate the hazard ratios (HR) and 95% confidence intervals (CI) for the associations between self-reported type 2 diabetes, high cholesterol, triglyceride and colorectal cancer risk.

Results

 Overall, 802 carriers were diagnosed with colorectal cancer at a median age of 42 years. A higher risk of colorectal cancer was observed in those with self-reported type-2 diabetes (HR 1.92; 95% CI, 1.03–3.58) and high cholesterol (HR 1.76; CI 1.23–2.52) compared with those without these conditions. There was no evidence of high triglyceride being associated with colorectal cancer risk.

Conclusion

For people with Lynch syndrome, self-reported type-2 diabetes mellitus and high cholesterol were associated with increased colorectal cancer risk.

Energy balance related lifestyle factors and risk of endometrial and colorectal cancer among individuals with lynch syndrome: a systematic review

Lifestyle factors related to energy balance, such as excess body weight, poor diet, and physical inactivity, are associated with risk of sporadic endometrial cancer (EC) and colorectal cancer (CRC). There are limited data on energy balance-related lifestyle factors and EC or CRC risk among individuals with lynch syndrome, who are at extraordinarily higher risk of developing EC or CRC. We conducted a systematic review of evidence related to weight status, weight change, dietary habits, and physical activity on EC and CRC risk among individuals with lynch syndrome. Findings are reported narratively. We searched Medline, EMBASE, CENTRAL, PubMed, and clinicaltrials.gov up to June 14th, 2018. In total, 1060 studies were identified and 16 were included. Three studies were related to EC and 13 to CRC. Overall, evidence suggests that weight status/weight change may not be associated with EC risk and multivitamin and folic-acid supplementation may be associated with decreased EC risk. Early-adulthood overweight/obese weight-status and adulthood weight-gain may be associated with increased CRC risk, whereas multivitamin supplementation, tea and high fruit intake, and physical activity may be associated with decreased CRC risk. Current evidence proposes that recommendations related to weight, some dietary habits, and physical activity recommended for the general public are also relevant to individuals with lynch syndrome. More research is needed, specifically prospective cohorts and randomized controlled trials, to determine if tailored recommendations are needed among individuals with lynch syndrome.

SNP association study in PMS2-associated Lynch syndrome

Lynch syndrome (LS) patients are at high risk of developing colorectal cancer (CRC). Phenotypic variability might in part be explained by common susceptibility loci identified in Genome Wide Association Studies (GWAS). Previous studies focused mostly on MLH1, MSH2 and MSH6 carriers, with conflicting results. We aimed to determine the role of GWAS SNPs in PMS2 mutation carriers. A cohort study was performed in 507 PMS2 carriers (124 CRC cases), genotyped for 24 GWAS SNPs, including SNPs at 11q23.1 and 8q23.3. Hazard ratios (HRs) were calculated using a weighted Cox regression analysis to correct for ascertainment bias. Discrimination was assessed with a concordance statistic in a bootstrap cross-validation procedure. Individual SNPs only had non-significant associations with CRC occurrence with HRs lower than 2, although male carriers of allele A at rs1321311 (6p21.31) may have increased risk of CRC (HR = 2.1, 95% CI 1.2–3.0). A polygenic risk score (PRS) based on 24 HRs had an HR of 2.6 (95% CI 1.5–4.6) for the highest compared to the lowest quartile, but had no discriminative ability (c statistic 0.52). Previously suggested SNPs do not modify CRC risk in PMS2 carriers. Future large studies are needed for improved risk stratification among Lynch syndrome patients.

Early-life obesity and adulthood colorectal cancer risk: a meta-analysis

Objective

This meta-analysis examines the relationship between early-life obesity and risk of colorectal cancer (CRC) in adulthood.

Methods

A systematic search of Google Scholar, PubMed, and reference data was conducted. Fifteen relevant studies were identified and meta-analyzed, for men and women separately. A random-effects model was used to compare the multivariable-adjusted relative risks (RR) of overall and subsite-specific CRC to the highest versus lowest categories of body mass index (BMI) in early life. Meta-regression was performed on factors that may have contributed to between-study heterogeneity.

Results

High early-life BMI was associated with a 39% increased risk of CRC in adult men (RR = 1.39, 95%CI = 1.20 – 1.62, P < 0.0001) and a 19% increased risk of CRC in adult women (RR = 1.19, 95%CI = 1.06 – 1.35, P = 0.004). No statistically significant heterogeneity was identified in meta-regression according to tumor subsite (RR = 1.06, 95%CI = 0.97 – 1.17, RR = 1.08, 95%CI = 0.99 – 1.18 for male and female proximal colon cancer; RR = 1.51, 95%CI = 1.22 – 1.87, RR = 1.08, 95%CI = 0.98 – 1.19 for male and female distal colon cancer; and RR = 1.39, 95%CI = 1.1 – 1.77, RR = 1.51, 95%CI = 0.94 – 2.03 for male and female rectal cancer) or other factors, including age of BMI assessment, self-reported or measured BMI, and adjustment for smoking.

Conclusions

The results suggest that high early-life BMI is associated with increased risk of CRC in adulthood. Further studies should investigate adult CRC risk in early-life obese individuals from non-Western countries and the underlying mechanisms by which early-life adiposity may influence CRC pathogenesis.

Body Mass Index and Long-Term Outcomes in Patients With Colorectal Cancer

Background: The association between body mass index (BMI) and colorectal cancer is unique. There are several patient- and tumor-related factors that affect this and associations are not entirely clear. The primary aim of this study is to examine the association between BMI and survival after colorectal cancer diagnosis.

Methods: Among 26,908 Mayo Clinic patients diagnosed with colorectal cancer between 1972 and 2017, 3,799 patients had information on BMI within 6 months prior to cancer diagnosis. Multivariable Cox regression models were used to assess the differences in overall survival between BMI groups in each cancer stage, controlling for age, gender, year of diagnosis, and cancer location. The impact of change of BMI at 30, 60, and 90 days on survival afterwards were also analyzed.

Results: Among 3,799 patients included in the study, there were 29% normal weight, 2% underweight, 36% overweight, and 33% obese patients. With all stages combined together, the overall 5-years survival rates for underweight, normal weight, overweight, and obese patients were 33, 56, 60, and 65%, respectively (p < 0.001). The results show that, the difference in overall survival was not statistically significant when underweight, overweight, and obese patients were compared to normal weight patients in stage 1 and stage 2, although there was a trend that overweight patients had better survival than normal weight group in stage 2 cancer patients (HR = 0.8, p = 0.086). In stage 3 and 4 patients combined, underweight group demonstrated a significant disadvantage (HR = 1.96, p = 0.007) for overall survival compared to the normal weight group. Additionally, post-diagnosis BMI drop more than 10% from either a previous time (HR = 1.88, p = 0.002) or pre-diagnosis time (HR = 1.61, p < 0.001) was associated with worse overall survival after adjusting for baseline variables.

Conclusions: BMI is an important consideration in patients with colorectal cancer. Outcomes are stage-dependent where in some situations obesity maybe an advantage. More importantly, being underweight is a significant negative predictor of outcome. The impact of drop in BMI or weight, on survival of CRC patients, needs to be studied further since this is potentially an actionable variable and a dynamic biomarker that may help improve outcome in these patients.

Physical activity and the risk of colorectal cancer in Lynch syndrome

Greater physical activity is associated with a decrease in risk of colorectal cancer for the general population; however, little is known about its relationship with colorectal cancer risk in people with Lynch syndrome, carriers of inherited pathogenic mutations in genes affecting DNA mismatch repair (MMR). We studied a cohort of 2,042 MMR gene mutations carriers (n = 807, diagnosed with colorectal cancer), from the Colon Cancer Family Registry. Self-reported physical activity in three age-periods (20-29, 30-49 and ≥50 years) was summarized as average metabolic equivalent of task hours per week (MET-hr/week) during the age-period of cancer diagnosis or censoring (near-term exposure) and across all age-periods preceding cancer diagnosis or censoring (long-term exposure). Weighted Cox regression was used to estimate the hazard ratio (HR) and 95% confidence intervals (CI) for the association between physical activity and colorectal cancer risk. Near-term physical activity was associated with a small reduction in the risk of colorectal cancer (HR ≥35 vs. <3.5 MET-hr/week, 0.71; 95% CI, 0.53-0.96). The strength and direction of associations were similar for long-term physical activity, although the associations were not nominally significant. Our results suggest that physical activity is inversely associated with the risk of colorectal cancer for people with Lynch syndrome; however, further confirmation is warranted. The potential modifying effect of physical activity on colorectal cancer risk in people with Lynch syndrome could be useful for risk prediction and support counseling advice for lifestyle modification to reduce cancer risk.

Alcohol consumption and early-onset risk of colorectal cancer in Japanese patients with Lynch syndrome: a cross-sectional study conducted by the Japanese Society for Cancer of the Colon and Rectum

We conducted this study to establish whether drinking alcohol alters the risk of early-onset colorectal cancer (CRC) in Japanese patients with Lynch syndrome (LS). The subjects were 66 LS patients with pathogenic mutation of mismatch repair genes (MLH1, MSH2, and MSH6) from the nationwide Japanese retrospective multicenter study. Cox proportional hazards modeling was used to investigate the factors correlating with early-onset CRC diagnosis, using clinical data such as gender, tobacco use, alcohol consumption, body mass index, gene mutation (MLH1, MSH2 vs MSH6), and family cancer history. Alcohol was significantly correlated with an increased risk of early-onset CRC [HR 2.44, 95% CI 1.13-5.16 (p = 0.02)], but tobacco use was not [HR 0.8, 95%CI 0.38-1.62 (p = 0.53)]. These findings suggest that alcohol consumption is correlated with an earlier onset of CRC in Japanese patients with LS.

Long-term weight loss after colorectal cancer diagnosis is associated with lower survival: The Colon Cancer Family Registry

BACKGROUND

Body weight is associated with colorectal cancer (CRC) risk and survival, but to the authors' knowledge, the impact of long-term postdiagnostic weight change is unclear. Herein, the authors investigated whether weight change over the 5 years after a diagnosis of CRC is associated with survival.

METHODS

CRC cases diagnosed from 1997 to 2008 were identified through 4 population-based cancer registry sites. Participants enrolled within 2 years of diagnosis and reported their height and weight 2 years prior. Follow-up questionnaires were administered approximately 5 years after diagnosis. Associations between change in weight (in kg) or body mass index (BMI) with overall and CRC-specific survival were estimated using Cox regression analysis adjusted for age, sex, American Joint Committee on Cancer stage of disease, baseline BMI, nonsteroidal anti-inflammatory drug use, smoking, time between diagnosis and enrollment, and study site.

RESULTS

At the 5-year postdiagnostic survey, 2049 participants reported higher (53%; median plus 5 kg), unchanged (12%), or lower (35%; median -4 kg) weight. Over a median of 5.1 years of subsequent follow-up (range, 0.3-9.9 years), 344 participants died (91 of CRC). Long-term weight loss (per 5 kg) was found to be associated with poorer overall survival (hazard ratio, 1.13; 95% confidence interval, 1.07-1.21) and CRC-specific survival (hazard ratio, 1.25; 95% confidence interval, 1.13-1.39). Significantly lower survival was similarly observed for relative weight loss (>5% vs ≤5% change), BMI reduction (per 1 unit), or BMI category change (overweight to normal vs remaining overweight).

CONCLUSIONS

Weight loss 5 years after a diagnosis of CRC was found to be significantly associated with decreased long-term survival, suggesting the importance of avoiding weight loss in survivors of CRC. Future research should attempt to further evaluate this association, accounting for whether this weight change was intentional or represents a marker of declining health. Cancer 2017;123:4701-4708. © 2017 American Cancer Society.

Body fatness at an early age and risk of colorectal cancer

While there is convincing evidence that excess body fatness in adulthood is positively associated with colorectal cancer risk, the association between body fatness at an early age (≤30 years) and the risk of colorectal cancer has been equivocal. The present meta-analysis was performed to clarify this association. PubMed and Web of Science databases were searched for relevant studies that investigated this association. The risk estimates from each study were transformed into a continuous variable for each 5 kg/m² increase in body mass index (BMI). A random effects model was used to calculate the summary relative risks (RRs) with 95% confidence intervals (CIs). A total of 15 observational studies (13 cohort studies and two case-control studies) were included in this meta-analysis. Each 5 kg/m² increase in BMI was significantly associated with a 13% (RR 1.13, 95% CI 1.08, 1.19), 17% (RR 1.17, 95% CI 1.09, 1.25) and 8% (RR 1.08, 95% CI 1.04, 1.11) higher risk of colorectal cancer overall, in men, and in women, respectively. Substantial heterogeneity was observed across studies. Based on the anatomic subsite, each 5 kg/m² increase in BMI was significantly associated with a 14% (RR 1.14, 95% CI 1.07, 1.22) higher risk of colon cancer, whereas no association (RR 1.03, 95% CI 0.95, 1.13) was observed with rectal cancer. In summary, body fatness at an early age may affect colon cancer risk later in life. Prevention of overweight and obesity in young individuals should be emphasized to prevent early-onset colon cancer attributed to excess body fatness.

Do alcoholic beverages, obesity and other nutritional factors modify the risk of familial colorectal cancer? A systematic review

PURPOSE

Individuals with family history of colorectal cancer are at higher risk of colorectal cancer than the general population. Until now, guidelines for familial colorectal cancer risk have only pointed at early diagnosis efforts via screening tests and surveillance, and payed scarce or no attention to lowering exposure to modifiable risk factors, notably nutritional factors.

METHODS

We conducted a systematic review of epidemiological studies investigating the associations between nutritional factors, family history of colorectal cancer, and colorectal cancer risk. From the 5312 abstracts identified until December 2016, 184 full text articles were examined for eligibility. Finally, 31 articles (21 from case-control studies, 9 from cohort studies and 1 from an intervention study) met inclusion criteria and were analyzed.

RESULTS

Mainly, the combinations of family history of colorectal cancer and higher consumptions of alcoholic beverages, red or processed meat, or overweight/obesity increase the risk of colorectal cancer. Consistently, a strong increase is observed with the combinations of family history of colorectal cancer and unhealthy dietary patterns/lifestyles. Statistically significant interactions between these nutritional factors, family history of colorectal cancer and colorectal cancer risk are reported. Other data are inconclusive and additional prospective studies are needed.

CONCLUSIONS

For the first time, our findings highlight that addressing high consumption of alcoholic beverages, red or processed meat, and overweight/obesity, and more largely the exposure to multiple unhealthy dietary/nutritional behaviors could offer new perspectives of prevention to individuals with family history of colorectal cancer. A better information of these patients and of health professionals on these nutritional modifiable risk factors is recommended.

Adolescent body mass index and erythrocyte sedimentation rate in relation to colorectal cancer risk

OBJECTIVE

Adult obesity and inflammation have been associated with risk of colorectal cancer (CRC); however, less is known about how adolescent body mass index (BMI) and inflammation, as measured by erythrocyte sedimentation rate (ESR), relate to CRC risk. We sought to evaluate these associations in a cohort of 239 658 Swedish men who underwent compulsory military enlistment examinations in late adolescence (ages 16-20 years).

DESIGN

At the time of the conscription assessment (1969-1976), height and weight were measured and ESR was assayed. By linkage to the national cancer registry, these conscripts were followed for CRC through 1 January 2010. Over an average of 35 years of follow-up, 885 cases of CRC occurred, including 501 colon cancers and 384 rectal cancers. Cox regression was used to estimate adjusted HRs and corresponding 95% CIs.

RESULTS

Compared with normal weight (BMI 18.5 to <25 kg/m(2)) in late adolescence, upper overweight (BMI 27.5 to <30 kg/m(2)) was associated with a 2.08-fold higher risk of CRC (95% CI 1.40 to 3.07) and obesity (BMI 30+ kg/m(2)) was associated with a 2.38-fold higher risk of CRC (95% CI 1.51 to 3.76) (p-trend: <0.001). Male adolescents with ESR (15+ mm/h) had a 63% higher risk of CRC (HR 1.63; 95% CI 1.08 to 2.45) than those with low ESR (<10 mm/h) (p-trend: 0.006). Associations did not significantly differ by anatomic site.

CONCLUSIONS

Late-adolescent BMI and inflammation, as measured by ESR, may be independently associated with future CRC risk. Further research is needed to better understand how early-life exposures relate to CRC.

Lynch syndrome risk management

Lynch syndrome has been known as hereditary non-polyposis colorectal cancer (HNPCC), and it is a dominantly inherited cancer syndrome caused by genetic mutations in cell mismatch repair genes, often leading to digestive system and female reproductive system tumors. At present, there is a high misdiagnosis rate for Lynch syndrome. This paper reviews the latest progress in Lynch syndrome risk management with regards to its monitoring, surgical treatment, pharmaceutical treatment, life style improvement and screening.

Multivitamin, calcium and folic acid supplements and the risk of colorectal cancer in Lynch syndrome

BACKGROUND

People with a DNA mismatch repair (MMR) gene mutation have a substantially elevated risk of colorectal cancer (CRC) but the modifiers of this risk are not well established. We investigated the association between dietary supplement intake and CRC risk for carriers.

METHODS

This study included 1966 (56% female) carriers of an MMR gene mutation (719 MLH1, 931 MSH2, 211 MSH6 and 105 PMS2) who were recruited from the USA, Canada, Australia and New Zealand into the Colon Cancer Family Registry between 1997 and 2012. Information on lifestyle factors including supplement intake was collected at the time of recruitment. Using Cox proportional hazards regression weighted to correct for ascertainment bias, we estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for associations between self-reported multivitamin, calcium and folic acid supplement intake and CRC risk.

RESULTS

Of 744 carriers with CRC, 18%, 6% and 5% reported intake of multivitamin, calcium and folic acid supplements for at least 1 month, respectively, compared with 27%, 11% and 10% of 1222 carriers without CRC. After adjusting for identified confounding variables, a decreased CRC risk was associated with multivitam inintake for at least 3 years (HR 0.47, 95% CI 0.32-0.69) and calcium intake for at least 3 years(HR 0.42, 95% CI 0.23-0.74), compared with never users. There was no evidence of an association between folic acid supplement intake and CRC risk (P = 0.82).

CONCLUSION

Intake of multivitamin and calcium supplements might be associated with a decreased risk of CRC for MMR gene mutation carriers.

Obesity, Aspirin, and Risk of Colorectal Cancer in Carriers of Hereditary Colorectal Cancer: A Prospective Investigation in the CAPP2 Study

PURPOSE

In the general population, increased adiposity is a significant risk factor for colorectal cancer (CRC), but whether obesity has similar effects in those with hereditary CRC is uncertain. This prospective study investigated the association between body mass index and cancer risk in patients with Lynch syndrome (LS).

PATIENTS AND METHODS

Participants with LS were recruited to the CAPP2 study, in which they were randomly assigned to receive aspirin 600 mg per day or aspirin placebo, plus resistant starch 30 g per day or starch placebo (2 × 2 factorial design). Mean intervention period was 25.0 months, and mean follow-up was 55.7 months.

RESULTS

During follow-up, 55 of 937 participants developed CRC. For obese participants, CRC risk was 2.41× (95% CI, 1.22 to 4.85) greater than for underweight and normal-weight participants (reference group), and CRC risk increased by 7% for each 1-kg/m(2) increase in body mass index. The risk of all LS-related cancers in obese people was 1.77× (95% CI, 1.06 to 2.96; P = .03) greater than for the reference group. In subgroup analysis, obesity was associated with 3.72× (95% CI, 1.41 to 9.81) greater CRC risk in patients with LS with MLH1 mutation, but no excess risk was observed in those with MSH2 or MSH6 mutation (P = .5). The obesity-related excess CRC risk was confined to those randomly assigned to the aspirin placebo group (adjusted hazard ratio, 2.75; 95% CI, 1.12 to 6.79; P = .03).

CONCLUSION

Obesity is associated with substantially increased CRC risk in patients with LS, but this risk is abrogated in those taking aspirin. Such patients are likely to benefit from obesity prevention and/or regular aspirin.

Early life body fatness and risk of colorectal cancer in u.s. Women and men-results from two large cohort studies

BACKGROUND

The association between body fatness before adulthood and later risk of colorectal cancer remains unclear. We hypothesized that, independent of adult body fatness, early life body fatness would be associated with a higher risk of developing colorectal cancer.

METHODS

We assessed body fatness during childhood and adolescence using a validated 9-level somatotype and inquired body weight in young adulthood in the Nurses' Health Study and Health Professionals Follow-up Study. We used the Cox proportional hazard regression modeling to estimate relative risks [RR, 95% confidence intervals (CI)] adjusting for adult body mass index (BMI) and other known colorectal cancer risk factors.

RESULTS

We identified 2,100 incident colorectal cancer cases (1,292 in women and 808 in men) during 22 years of follow-up. Among women, the RR (95% CI) for childhood body fatness of level 5 or higher versus level 1 was 1.28 (1.04-1.58; Ptrend = 0.08) and for adolescent body fatness, it was 1.27 (1.01-1.60; Ptrend = 0.23). The corresponding RRs for men were 1.04 (0.82-1.31; Ptrend = 0.48) and 0.98 (0.75-1.27; Ptrend = 0.20), respectively. Results were generally similar across anatomic subsites within the colorectum. In addition, the RRs comparing BMI categories ≥27.5 to <19 kg/m(2) were 1.44 (1.06-1.95, at age 18; Ptrend = 0.009) for women and 1.18 (0.84-1.65, at age 21; Ptrend = 0.57) for men.

CONCLUSION

Increased body fatness in early life, independent of adult obesity, might be a risk factor for colorectal cancer in women, but we observed a weaker association in men.

IMPACT

Our findings support the growing evidence that early life body fatness affects the risk of colorectal cancer many decades later.

Clinical significance of mismatch repair gene expression in sporadic colorectal cancer

Mismatch repair (MMR) genes play an important role in the occurrence and development of sporadic colorectal cancer; however, the effect of MMR genes on clinicopathological features and prognosis remains unclear. The aim of the present study was to observe the clinical significance of MMR gene expression in sporadic colorectal cancer. Clinicopathological data and postoperative samples from 404 patients with sporadic colorectal cancer were obtained from the Affiliated Tumor Hospital of Xinjiang Medical University. The immunohistochemistry PV-9000 two-step method was performed to measure the protein expression of human mutL homolog 1 (hMLH1), human mutS homolog (hMSH) 2, human postmeiotic segregation increased 2 (hPSM2) and hMSH6. Differences in clinicopathological features, family history and survival time subsequent to surgery between groups with normal and aberrant MMR protein (MMRP) expression were compared. A total of 27.23% of all patients showed aberrant nuclear staining of MMRP. Among the patients with aberrant MMRP expression, a higher proportion of patients showed aberrant expression of more than one type of MMRP than aberrant expression of only one type of MMRP. Aberrant expression of hMLH1/hPSM2 was most commonly observed (29/404). In addition, aberrant MMRP expression in colorectal cancer was indicated predominantly in the right hemicolon. Histological type primarily showed mucinous adenocarcinoma. In addition, with increasing body mass index (BMI), the MMRP deficiency rate was also shown to increase gradually. There was a close association between MMRP expression deficiency and family history of cancer (P<0.05). For TNM stage III patients, the Kaplan-Meier survival curve showed that the aberrant MMRP expression group had a three-year disease-free survival (DFS) rate of 66.67%, which was longer than the DFS rate of the normal group (55.41%), with no statistical difference (P>0.05). In conclusion, the immunohistochemistry PV-9000 two-step method can be used to measure MMRP expression in colorectal cancer. Aberrant MMRP expression is closely correlated with tumor location, histological type, BMI and tumor family history in sporadic colorectal cancer. Aberrant MMRP expression may have an effect on the prognosis of stage III patients.

The genetic basis of Lynch syndrome and its implications for clinical practice and risk management

Lynch syndrome is the most common cause of hereditary colon cancer, and accounts for as much as 3% of all colon and endometrial cancers. The identification and management of individuals with Lynch syndrome have evolved over the past 20 years, yet the syndrome remains vastly underdiagnosed. It is important for clinicians to recognize individuals and families who are at risk in order to be able to manage them appropriately and reduce their morbidity and mortality from this condition. This review will touch on the history of Lynch syndrome, the current knowledge of genotype–phenotype correlations, the cancers associated with Lynch syndrome, and management of individuals who are gene carriers.

Cancer risks for MLH1 and MSH2 mutation carriers

We studied 17,576 members of 166 MLH1 and 224 MSH2 mutation-carrying families from the Colon Cancer Family Registry. Average cumulative risks of colorectal cancer (CRC), endometrial cancer (EC), and other cancers for carriers were estimated using modified segregation analysis conditioned on ascertainment criteria. Heterogeneity in risks was investigated using a polygenic risk modifier. Average CRC cumulative risks at the age of 70 years (95% confidence intervals) for MLH1 and MSH2 mutation carriers, respectively, were estimated to be 34% (25%-50%) and 47% (36%-60%) for male carriers and 36% (25%-51%) and 37% (27%-50%) for female carriers. Corresponding EC risks were 18% (9.1%-34%) and 30% (18%-45%). A high level of CRC risk heterogeneity was observed (P < 0.001), with cumulative risks at the age of 70 years estimated to follow U-shaped distributions. For example, 17% of male MSH2 mutation carriers have estimated lifetime risks of 0%-10% and 18% have risks of 90%-100%. Therefore, average risks are similar for the two genes but there is so much individual variation about the average that large proportions of carriers have either very low or very high lifetime cancer risks. Our estimates of CRC and EC cumulative risks for MLH1 and MSH2 mutation carriers are the most precise currently available.

Perceived versus predicted risks of colorectal cancer and self-reported colonoscopies by members of mismatch repair gene mutation-carrying families who have declined genetic testing

People carrying germline mutations in mismatch repair genes are at high risk of colorectal cancer (CRC), yet about half of people from mutation-carrying families decline genetic counselling and/or testing to identify mutation status. We studied the association of quantitative measures of risk perception, risk prediction and self-reported screening colonoscopy in this elusive yet high-risk group. The sample of 26 participants (mean age 43.1 years, 14 women) in the Australasian Colorectal Cancer Family Registry were relatives of mutation carriers; had not been diagnosed with any cancer at the time of recruitment and had declined an invitation to attend genetic counselling and/or testing. A structured elicitation protocol captured perceived CRC risk over the next 10 years. Self-reported colonoscopy screening was elicited during a 45-minute semi-structured interview. Predicted 10-year CRC risk based on age, gender, known mutation status and family history was calculated using "MMRpro." Mean perceived 10-year risk of CRC was 31 % [95 % CI 21, 40], compared with mean predicted risk of 4 % [2, 7] (p < 0.001); this was independent of age and sex (p = 0.9). Among those reporting any medical advice and any screening colonoscopy (n = 18), those with higher risk perception had less frequent colonoscopy (Pearson's r = 0.49 [0.02, 0.79]). People who decline genetic testing for CRC susceptibility mutations perceive themselves to be at substantially higher risk than they really are. Those with high perceived risk do not undertake screening colonoscopy more often than those who perceive themselves to be at average risk.

Revised guidelines for the clinical management of Lynch syndrome (HNPCC): recommendations by a group of European experts

Lynch syndrome (LS) is characterised by the development of colorectal cancer, endometrial cancer and various other cancers, and is caused by a mutation in one of the mismatch repair genes: MLH1, MSH2, MSH6 or PMS2. In 2007, a group of European experts (the Mallorca group) published guidelines for the clinical management of LS. Since then substantial new information has become available necessitating an update of the guidelines. In 2011 and 2012 workshops were organised in Palma de Mallorca. A total of 35 specialists from 13 countries participated in the meetings. The first step was to formulate important clinical questions. Then a systematic literature search was performed using the Pubmed database and manual searches of relevant articles. During the workshops the outcome of the literature search was discussed in detail. The guidelines described in this paper may be helpful for the appropriate management of families with LS. Prospective controlled studies should be undertaken to improve further the care of these families.

Are the common genetic variants associated with colorectal cancer risk for DNA mismatch repair gene mutation carriers?

BACKGROUND

Genome-wide association studies have identified at least 15 independent common genetic variants associated with colorectal cancer (CRC) risk. The aim of this study was to investigate whether 11 of these variants are associated with CRC risk for carriers of germline mutations in DNA mismatch repair (MMR) genes.

METHODS

A total of 927 MMR gene mutation carriers (360 MLH1, 442 MSH2, 85 MSH6 and 40 PMS2) from 315 families enrolled in the Colon Cancer Family Registry, were genotyped for the single nucleotide polymorphisms (SNPs): rs16892766 (8q23.3), rs6983267 (8q24.21), rs719725 (9p24), rs10795668 (10p14), rs3802842 (11q23.1), rs4444235 (14q22.2), rs4779584 (15q13.3), rs9929218 (16q22.1), rs4939827 (18q21.1), rs10411210 (19q13.1) and rs961253 (20p12.3). We used a weighted Cox regression to estimate CRC risk for homozygous and heterozygous carriers of the risk allele compared with homozygous non-carriers as well as for an additive per allele model (on the log scale).

RESULTS

Over a total of 40,978 person-years observation, 426 (46%) carriers were diagnosed with CRC at a mean age of 44.3 years. For all carriers combined, we found no evidence of an association between CRC risk and the total number of risk alleles (hazard ratio [HR] per risk allele=0.97, 95% confidence interval [CI]=0.88-1.07, p=0.52).

CONCLUSIONS

We found no evidence that the SNPs associated with CRC in the general population are modifiers of the risk for MMR gene mutation carriers overall, and therefore any evidence of proven clinical utility in Lynch syndrome.

Association between body mass index and colorectal cancer: Recent research progress

Colorectal cancer (CRC) is a common digestive system disease posing a serious threat to people's health. There are about 1. 2 million new cases of CRC diagnosed worldwide each year, and the figure in China is 130 thousand. The socio-economic development and changes in diet and habits in China have led to a significant increase in both the incidence and mortality of CRC. The average age of onset of CRC in China is about 20 years old lower than that in Western countries, ranking second among all malignant tumors. The incidence and mortality of CRC in some developed regions of China, however, is close to those in Western developed countries. The development of CRC results from multiple factors, and nearly a quarter of patients with CRC could have avoided suffering from this disease by making favorable lifestyle habits. Nowadays, two-thirds of adults are fighting against overweight and obesity. Numerous recent studies indicate that high body mass index (BMI) is related with colorectal cancer. This article will review recent advances in understanding the relationship between BMI and CRC.