Proportion of colon cancer attributable to lifestyle in a cohort of US women

Spatial analysis of risk factors related to colorectal cancer in Iran: An ecological study

Background and aims

Colorectal cancer is the third most common cancer worldwide, accounting for 10% of cancer deaths. Therefore, this study was performed with the aim of spatial analysis of risk factors for colorectal cancer in Iran.

Method

This study was conducted ecologically using STEPS information (The WHO Stepwise Approach to NCD Risk Factor Surveillance) in Iran. To analyze the data, the researcher used cluster analysis and Geographically Weighted Regression methods with the help of ArcGIS version 10.

Results

The results of OLS analysis showed that there was a significant relationship between tobacco consumption (B = 0.571, p-value = 0.044) and smoking (B = 0.772, p-value = 0.010) and the incidence of colon cancer (CC). There was also a significant relationship between abdominal obesity and the incidence of rectal cancer (RC) (B = 0.061, p-value = 0.027).

Conclusion

This study showed that (CC) high-risk areas are located in central and northern parts of Iran, and the significant risk factors related to CC and RC were found to be tobacco use, cigarette smoking, and abdominal obesity. These findings are helpful to inform policymakers to plan screening services to reduce CC and RC, especially in high-risk populations.

Aspirin Use and Incidence of Colorectal Cancer According to Lifestyle Risk

Importance

Aspirin reduces the risk of colorectal cancer (CRC). Identifying individuals more likely to benefit from regular aspirin use for CRC prevention is a high priority.

Objective

To assess whether aspirin use is associated with the risk of CRC across different lifestyle risk factors.

Design, Setting, and Participants

A prospective cohort study among women in the Nurses' Health Study (1980-2018) and men in the Health Professionals Follow-Up Study (1986-2018) was conducted. Data analysis was performed from October 1, 2021, to May 22, 2023.

Exposures

A healthy lifestyle score was calculated based on body mass index, alcohol intake, physical activity, diet, and smoking with scores ranging from 0 to 5 (higher values corresponding to a healthier lifestyle). Regular aspirin use was defined as 2 or more standard tablets (325 mg) per week.

Main Outcome and Measures

Outcomes included multivariable-adjusted 10-year cumulative incidence of CRC, absolute risk reduction (ARR), and number needed to treat associated with regular aspirin use by lifestyle score and multivariable-adjusted hazard ratios for incident CRC across lifestyle scores.

Results

The mean (SD) baseline age of the 107 655 study participants (63 957 women from the Nurses' Health Study and 43 698 men from the Health Professionals Follow-Up Study) was 49.4 (9.0) years. During 3 038 215 person-years of follow-up, 2544 incident cases of CRC were documented. The 10-year cumulative CRC incidence was 1.98% (95% CI, 1.44%-2.51%) among participants who regularly used aspirin compared with 2.95% (95% CI, 2.31%-3.58%) among those who did not use aspirin, corresponding to an ARR of 0.97%. The ARR associated with aspirin use was greatest among those with the unhealthiest lifestyle scores and progressively decreased with healthier lifestyle scores (P < .001 for additive interaction). The 10-year ARR for lifestyle scores 0 to 1 (unhealthiest) was 1.28%. In contrast, the 10-year ARR for lifestyle scores 4 to 5 (healthiest) was 0.11%. The 10-year number needed to treat with aspirin was 78 for participants with lifestyle scores 0 to 1, 164 for score 2, 154 for score 3, and 909 for scores 4 to 5. Among the components of the healthy lifestyle score, the greatest differences in ARR associated with aspirin use were observed for body mass index and smoking.

Conclusions and Relevance

In this cohort study, aspirin use was associated with a greater absolute reduction in risk of CRC among individuals with less healthy lifestyles. The findings of the study suggest that lifestyle risk factors may be useful to identify individuals who may have a more favorable risk-benefit profile for cancer prevention with aspirin.

The anticancer effect of potential probiotic L. fermentum and L. plantarum in combination with 5-fluorouracil on colorectal cancer cells

5-Fluorouracil (5-FU) is an effective chemotherapy drug in the treatment of colorectal cancer (CRC). However, auxiliary or alternative therapies must be sought due to its resistance and potential side effects. Certain probiotic metabolites exhibit anticancer properties. In this study evaluated the anticancer and potential therapeutic activities of cell extracts potential probiotic strains, Limosilactobacillus fermentum and Lactiplantibacillus plantarum isolated from the mule milk and the standard probiotic strain Lacticaseibacillus rhamnosus GG (LGG) against the human colon cancer cell line (HT-29) and the normal cell line (HEK-293) alone or in combination with 5-FU. In this study, L. plantarum and L. fermentum, which were isolated from mule milk, were identified using biochemical and molecular methods. Their probiotic properties were investigated in vitro and compared with the standard probiotic strain of the species L. rhamnosus GG. The MTT assay, acridine orange/ethidium bromide (AO/EB) fluorescent staining, and flow cytometry were employed to measure the viability of cell lines, cell apoptosis, and production rates of Th17 cytokines, respectively. The results demonstrated that the combination of lactobacilli cell extracts and 5-FU decreased cell viability and induced apoptosis in HT-29 cells. Furthermore, this combination protected HEK-293 cells from the cytotoxic effects of 5-FU, enhancing their viability and reducing apoptosis. Moreover, the combination treatment led to an increase in the levels of IL-17A, IFN-γ, and TNF-α, which can enhance anti-tumor immunity. In conclusion, the cell extracts of the lactobacilli strains probably can act as a potential complementary anticancer therapy.

Genome-Wide Gene-Environment Interaction Analyses to Understand the Relationship between Red Meat and Processed Meat Intake and Colorectal Cancer Risk

BACKGROUND

High red meat and/or processed meat consumption are established colorectal cancer risk factors. We conducted a genome-wide gene-environment (GxE) interaction analysis to identify genetic variants that may modify these associations.

METHODS

A pooled sample of 29,842 colorectal cancer cases and 39,635 controls of European ancestry from 27 studies were included. Quantiles for red meat and processed meat intake were constructed from harmonized questionnaire data. Genotyping arrays were imputed to the Haplotype Reference Consortium. Two-step EDGE and joint tests of GxE interaction were utilized in our genome-wide scan.

RESULTS

Meta-analyses confirmed positive associations between increased consumption of red meat and processed meat with colorectal cancer risk [per quartile red meat OR = 1.30; 95% confidence interval (CI) = 1.21-1.41; processed meat OR = 1.40; 95% CI = 1.20-1.63]. Two significant genome-wide GxE interactions for red meat consumption were found. Joint GxE tests revealed the rs4871179 SNP in chromosome 8 (downstream of HAS2); greater than median of consumption ORs = 1.38 (95% CI = 1.29-1.46), 1.20 (95% CI = 1.12-1.27), and 1.07 (95% CI = 0.95-1.19) for CC, CG, and GG, respectively. The two-step EDGE method identified the rs35352860 SNP in chromosome 18 (SMAD7 intron); greater than median of consumption ORs = 1.18 (95% CI = 1.11-1.24), 1.35 (95% CI = 1.26-1.44), and 1.46 (95% CI = 1.26-1.69) for CC, CT, and TT, respectively.

CONCLUSIONS

We propose two novel biomarkers that support the role of meat consumption with an increased risk of colorectal cancer.

IMPACT

The reported GxE interactions may explain the increased risk of colorectal cancer in certain population subgroups.

Curcumin-loaded porous particles functionalized with pH-responsive cell-penetrating peptide for colorectal cancer targeted drug delivery

The anticancer properties of curcumin have been broadly examined in several shapes, such as nanoparticles and nanocomposite structures. Despite its benefits, curcumin also has some disadvantages, including rapid metabolism, poor absorption, and rapid systemic excretion. Therefore, numerous strategies have been used to increase curcumin's bioavailability. One of these approaches is the use of porous particles like aerogels as drug carriers. Aerogels are special due to their peculiar physical structure. They have a high specific surface area, a significant amount of porosity, and a solid composition, which make them a good choice for drug delivery systems. In the present study, a pH-sensitive aerogel was constructed and evaluated for targeted drug delivery of curcumin to colon cancer. To control the release of curcumin, trehalose was used as a coating agent, and PLP (poly(l-lysine isophthalamide)) was used as a targeted drug delivery agent. PLP is a pseudo-peptidic polymer that increases the cell permeability. In order to investigate and compare the synthesized aerogel before and after loading curcumin and coating with trehalose, physicochemical characterization analyses were performed. Finally, the efficacy of the final formulation was evaluated on HT29 colon cells using the cell bioavailability test. The results indicated the successful synthesis of the aerogel with porous structure with solitary cavities. The trehalose coating performed well, preventing drug release at lower pH but allowing the drug to be released at its intended site. The designed curcumin-loaded porous particles functionalized with PLP showed significant efficacy due to increasing penetration of curcumin into cells, and has potential for use as a new drug carrier with dual effectivity in cancer therapy.

A Scoring Method to Prioritize Fecal Occult Blood Testing as a First Step in Colorectal Cancer Screening in Resource-Limited Settings

This study aims to develop a scoring method that can be used by primary care physicians from remote areas or resource-limited settings to estimate the need for fecal occult blood testing (FOBT) as a first step in colorectal cancer screening. This method relies on several modifiable risk factors that can influence a positive FOBT, an indication of the presence of colorectal polyps, or even colorectal cancer. The scoring method considers, besides the age and gender of the patient, the body mass index (BMI), smoking status, and the diagnoses of diabetes mellitus (type 2 diabetes), dyslipidemia, and hypertension. It does not need any paraclinical exams, which is an advantage when access or material resources are limited. The retrospective study was spread over forty-three months, respectively, from October 2019 to April 2023, and included 112 patients. The score that we designed is a numerical value between 0 and 7. The values between 0 and 3 represent a smaller risk of a positive FOBT (9.68%), values 4 and 5 represent a medium risk (14.75%), while values 6 and 7 represent a greater risk (40%). Using this score, a physician can determine if a patient has a greater risk and recommend it to prioritize taking a FOB test.

The burden of colon cancer attributable to modifiable factors-The Norwegian Women and Cancer Study

Colon cancer is the second most frequently diagnosed cancer in women in Norway, where incidence rates of colon cancer increased 3-fold between 1955 and 2014, for unknown reasons. We aimed to assess the burden of colon cancer attributable to modifiable risk factors in Norwegian women using the data from the Norwegian Women and Cancer (NOWAC) study. Self-reported information from 35 525 women from the NOWAC study were available. These included the following exposures: smoking status, alcohol consumption, body mass index, physical activity, intake of calcium, fibers, and red and processed meat. Colon cancer cases were identified from the Cancer Registry of Norway. A parametric piecewise constant hazards model was used to estimate the strength of exposure-cancer associations. Population attributable fractions with 95% confidence intervals (CIs) were calculated considering competing risk of death. The fraction of incident colon cancer attributable to ever smoking was 18.7% (95% CI 4.7%-30.6%), low physical activity 10.8% (95% CI -0.7% to 21.0%), alcohol consumption 14.5% (95% CI -2.8% to 28.9%), and low intake of calcium 10.0% (95% CI -7.8% to 24.8%). A small proportion of colon cancer cases was attributable to combined intake of red and processed meat over 500 g/week, overweight/obesity, and low intake of fibers. Jointly, these seven risk factors could explain 46.0% (95% CI 23.0%-62.4%) of the colon cancer incidence burden. Between 23% and 62% of the colon cancer burden among women in Norway was attributable to modifiable risk factors, indicating an important preventive potential of a healthy lifestyle.

Adherence to a healthy lifestyle in relation to colorectal cancer incidence and all-cause mortality after endoscopic polypectomy: A prospective study in three U.S. cohorts

It remains unknown whether maintenance of a healthy lifestyle after endoscopic polypectomy could still confer benefit for colorectal cancer (CRC) incidence and mortality. In this study, we defined a healthy lifestyle score based on body mass index, smoking, physical activity, alcohol consumption and diet (range, 0-5). We used Cox proportional hazards regression to estimate the hazard ratios (HRs) for the associations of healthy lifestyle score and individual lifestyle factors with CRC incidence and all-cause mortality. During a median of 10 years of follow-up of 24 668 participants who underwent endoscopic polypectomy, we documented 161 CRC cases and 4857 all-cause deaths. A higher healthy lifestyle score after endoscopic polypectomy was associated with lower risk of CRC and all-cause mortality. Compared with individuals with 0 to 1 healthy lifestyle factors, those with 2, 3 and 4 to 5 healthy lifestyle factors had a HR for CRC risk of 0.86 (95% confidence interval [CI], 0.60-1.24), 0.73 (95% CI, 0.47-1.14) and 0.52 (95% CI, 0.27-1.01), respectively (Ptrend  = .03). The corresponding HR (95% CI) for all-cause mortality was 0.83 (95% CI, 0.76-0.90), 0.63 (95% CI, 0.56-0.70) and 0.56 (95% CI, 0.48-0.65), respectively (Ptrend  < .0001). In the joint analysis of pre- and postpolypectomy periods, patients with a healthy postpolypectomy lifestyle had a lower incidence of CRC regardless of their prepolypectomy exposure, whereas those with a healthy lifestyle in both periods had a lower mortality than those with an unhealthy lifestyle in either period. In conclusion, adherence to a healthy lifestyle after polypectomy may confer significant benefit for CRC prevention and reduction in all-cause mortality.

Childhood socioeconomic status, healthy lifestyle, and colon cancer risk in a cohort of U.S. women

Colon cancer is the third most common cancer in the US. While the socioeconomic status -health gradient has been established, findings linking adult socioeconomic status to colon cancer incidence specifically are mixed. Considering childhood socioeconomic status (CSES) and relevant risk factors, including related lifestyle behaviors, may provide more insight. At baseline in 1976, women from the Nurses' Health Study reported CSES as defined by parents' occupation when participants were age 16. Lifestyle-related factors (i.e., physical activity, body mass index, diet, alcohol, and tobacco consumption) were self-reported in 1988 or 1990, and every 4 years thereafter until 2016. Cox regression models estimated hazards ratio (HR) and 95% confidence intervals (CIs) of adopting an unhealthy lifestyle (N = 22,507) and developing colon cancer (N = 100,921) between 1976 and 2016, separately, across parents' occupation levels. During follow-up, 2342 cases of colon cancer occurred. Compared to women whose parents were white collar workers, women whose parents were farmers had lower colon cancer risk (HR = 0.84; 95%CI: 0.72, 0.98), but no differences were evident for women whose parents were blue collar workers in models adjusting for age and familial history of colon cancer. Using the same comparison group, risk of adopting an unhealthy lifestyle over follow-up was not significantly different in women with farmer parents (HR = 0.96, 95% CI: 0.91, 1.02), while children of blue collar workers had slightly greater risk (HR = 1.07; 95%CI: 1.03, 1.12) in age-adjusted models. These findings suggest the impact of CSES on colon cancer risk is modest and varies across outcomes and occupational status.

Combined Effect of Healthy Lifestyle Factors and Risks of Colorectal Adenoma, Colorectal Cancer, and Colorectal Cancer Mortality: Systematic Review and Meta-Analysis

Background

In addition to adiposity, lifestyle factors such as poor diet, low physical activity, alcohol intake and smoking are noted to be associated with the development of colorectal cancer (CRC). This study aims to investigate the association and dose-response relationship between adherence to a healthy lifestyle and CRC risk.

Methods

A systematic literature search was conducted in MEDLINE and EMBASE for studies examining multiple lifestyle factors with risk of CRC, incident colorectal adenoma (CRA), and CRC-specific mortality through June 2021 without restrictions on language or study design. Meta-analysis was performed to pool hazard ratios using random-effects model. Subgroup analyses were performed based upon study and sample characteristics. Random-effects dose-response analysis was also conducted for CRC risk to assess the effect of each additional healthy lifestyle factor.

Results

A total of 28 studies (18 cohort studies, eight case-control studies, and two cross-sectional study) were included. When comparing subjects with the healthiest lifestyle to those with the least healthy lifestyle, the pooled HR was statistically significant for CRC (0.52, 95% CI 0.44-0.63), colon cancer (0.54, 95% CI 0.44-0.67), rectal cancer (0.51, 95% CI 0.37-0.70), CRA (0.39, 95% CI 0.29-0.53), and CRC-specific mortality (0.65, 95% CI 0.52-0.81). The pooled HR for CRC was 0.91 (95% CI: 0.88-0.94) for each increase in the number of healthy lifestyles. The inverse association between healthy lifestyle and CRC risk was consistently observed in all subgroups (HR ranging from 0.26 to 0.86).

Conclusions

Adoption of a higher number of healthy lifestyles is associated with lower risk of CRC, CRA, and CRC-specific mortality. Promoting healthy lifestyle could reduce the burden of CRC.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=231398, identifier CRD42021231398.

Associations of Evolutionary-Concordance Diet and Lifestyle Pattern Scores with Incident, Sporadic Colorectal Adenoma in a Pooled Case-Control Study

Differences in diet and lifestyle relative to those of our Paleolithic-era ancestors may explain current high incidences of chronic diseases, including colorectal cancer (CRC), in Westernized countries. Previously reported evolutionary-concordance diet and lifestyle pattern scores, reflecting closeness of diet and lifestyle patterns to those of Paleolithic-era humans, were associated with lower CRC incidence. Separate and joint associations of the scores with colorectal adenoma among men and women are unknown. To address this, we pooled data from three case-control studies of incident, sporadic colorectal adenomas (n = 771 cases, 1,990 controls), used participants' responses to food frequency and lifestyle questionnaires to calculate evolutionary-concordance diet and lifestyle pattern scores, and estimated the scores' associations with adenomas using multivariable unconditional logistic regression. The multivariable-adjusted odds ratios comparing those in the highest relative to the lowest diet and lifestyle score quintiles were 0.84 (95% confidence interval [CI] 0.62, 1.12; P_trend:0.03) and 0.41 (95% CI 0.29, 0.59; P_trend:<0.0001), respectively. The inverse associations were stronger for high-risk adenomas, and among those with both high relative to those with both low diet and lifestyle scores. These results suggest that more evolutionary-concordant diet and lifestyle patterns, separately and jointly, may be associated with lower risk for incident, sporadic colorectal adenoma.Supplemental data for this article is available online at https://doi.org/10.1080/01635581.2021.2002919 .

Long-Term Colorectal Cancer Incidence and Mortality After Colonoscopy Screening According to Individuals' Risk Profiles

BACKGROUND

It remains unknown whether the benefit of colonoscopy screening against colorectal cancer (CRC) and the optimal age to start screening differ by CRC risk profile.

METHODS

Among 75 873 women and 42 875 men, we defined a CRC risk score (0-8) based on family history, aspirin, height, body mass index, smoking, physical activity, alcohol, and diet. We calculated colonoscopy screening-associated hazard ratios and absolute risk reductions (ARRs) for CRC incidence and mortality and age-specific CRC cumulative incidence according to risk score. All statistical tests were 2-sided.

RESULTS

During a median of 26 years of follow-up, we documented 2407 CRC cases and 874 CRC deaths. Although the screening-associated hazard ratio did not vary by risk score, the ARRs in multivariable-adjusted 10-year CRC incidence more than doubled for individuals with scores 6-8 (ARR = 0.34%, 95% confidence interval [CI] = 0.26% to 0.42%) compared with 0-2 (ARR = 0.15%, 95% CI = 0.12% to 0.18%, Ptrend < .001). Similar results were found for CRC mortality (ARR = 0.22%, 95% CI = 0.21% to 0.24% vs 0.08%, 95% CI = 0.07% to 0.08%, Ptrend < .001). The ARR in mortality of distal colon and rectal cancers was fourfold higher for scores 6-8 than 0-2 (distal colon cancer: ARR = 0.08%, 95% CI = 0.07% to 0.08% vs 0.02%, 95% CI = 0.02% to 0.02%, Ptrend < .001; rectal cancer: ARR = 0.08%, 95% CI = 0.08% to 0.09% vs 0.02%, 95% CI = 0.02% to 0.03%, Ptrend < .001). When using age 45 years as the benchmark to start screening, individuals with risk scores of 0-2, 3, 4, 5, and 6-8 attained the threshold CRC risk level (10-year cumulative risk of 0.47%) at age 51 years, 48 years, 45 years, 42 years, and 38 years, respectively.

CONCLUSIONS

The absolute benefit of colonoscopy screening is more than twice higher for individuals with the highest than lowest CRC risk profile. Individuals with a high- and low-risk profile may start screening up to 6-7 years earlier and later, respectively, than the recommended age of 45 years.

The Impact of Probiotics on Intestinal Mucositis during Chemotherapy for Colorectal Cancer: A Comprehensive Review of Animal Studies

Colorectal cancer (CRC) is the second most commonly diagnosed cancer in females (incidence 16.4/10,000) and the third in males (incidence 23.4/10,000) worldwide. Surgery, chemotherapy (CTx), radiation therapy (RTx), or a combined treatment of those are the current treatment modalities for primary CRC. Chemotherapeutic drug-induced gastrointestinal (GIT) toxicity mainly presents as mucositis and diarrhea. Preclinical studies revealed that probiotic supplementation helps prevent CTx-induced side effects by reducing oxidative stress and proinflammatory cytokine production and promoting crypt cell proliferation. Moreover, probiotics showed significant results in preventing the loss of body weight (BW) and reducing diarrhea. However, further clinical studies are needed to elucidate the exact doses and most promising combination of strains to reduce or prevent chemotherapy-induced side effects. The aim of this review is to overview currently available literature on the impact of probiotics on CTx-induced side effects in animal studies concerning CRC treatment and discuss the potential mechanisms based on experimental studies' outcomes.

Cannabinoids and Endocannabinoid System Changes in Intestinal Inflammation and Colorectal Cancer

Despite the multiple preventive measures and treatment options, colorectal cancer holds a significant place in the world's disease and mortality rates. The development of novel therapy is in critical need, and based on recent experimental data, cannabinoids could become excellent candidates. This review covered known experimental studies regarding the effects of cannabinoids on intestinal inflammation and colorectal cancer. In our opinion, because colorectal cancer is a heterogeneous disease with different genomic landscapes, the choice of cannabinoids for tumor prevention and treatment depends on the type of the disease, its etiology, driver mutations, and the expression levels of cannabinoid receptors. In this review, we describe the molecular changes of the endocannabinoid system in the pathologies of the large intestine, focusing on inflammation and cancer.

The Sulfur Microbial Diet and Risk of Colorectal Cancer by Molecular Subtypes and Intratumoral Microbial Species in Adult Men

INTRODUCTION

We recently described the sulfur microbial diet, a pattern of intake associated with increased gut sulfur-metabolizing bacteria and incidence of distal colorectal cancer (CRC). We assessed whether this risk differed by CRC molecular subtypes or presence of intratumoral microbes involved in CRC pathogenesis (Fusobacterium nucleatum and Bifidobacterium spp.).

METHODS

We performed Cox proportional hazards modeling to examine the association between the sulfur microbial diet and incidence of overall and distal CRC by molecular and microbial subtype in the Health Professionals Follow-Up Study (1986-2012).

RESULTS

We documented 1,264 incident CRC cases among 48,246 men, approximately 40% of whom had available tissue data. After accounting for multiple hypothesis testing, the relationship between the sulfur microbial diet and CRC incidence did not differ by subtype. However, there was a suggestion of an association by prostaglandin synthase 2 (PTGS2) status with a multivariable adjusted hazard ratio for highest vs lowest tertile of sulfur microbial diet scores of 1.31 (95% confidence interval: 0.99-1.74, Ptrend = 0.07, Pheterogeneity = 0.04) for PTGS2-high CRC. The association of the sulfur microbial diet with distal CRC seemed to differ by the presence of intratumoral Bifidobacterium spp. with an adjusted hazard ratio for highest vs lowest tertile of sulfur microbial diet scores of 1.65 (95% confidence interval: 1.14-2.39, Ptrend = 0.01, Pheterogeneity = 0.03) for Bifidobacterium-negative distal CRC. We observed no apparent heterogeneity by other tested molecular markers.

DISCUSSION

Greater long-term adherence to the sulfur microbial diet could be associated with PTGS2-high and Bifidobacterium-negative distal CRC in men. Additional studies are needed to further characterize the role of gut microbial sulfur metabolism and CRC.

Self-reported Metabolic Risk Factor Associations with Adenomatous, Sessile Serrated, and Synchronous Adenomatous and Sessile Serrated Polyps

Studies have found a positive association between metabolic risk factors, such as obesity and diabetes, and adenomatous polyps (AP). However, fewer studies have assessed the association between sessile serrated polyps (SSP) or synchronous diagnosis of APs and SSPs (synch polyps). Study participants (N = 1,370; ages 40-85) undergoing screening colonoscopy were enrolled between August 2016 and February 2020. Self-reported metabolic risk factors, including diabetes, hypertension, hyperlipidemia, and overweight/obesity, were evaluated for associations with new diagnoses of APs, SSPs, and synch polyps at the present colonoscopy. Average participant age was 60.73 ± 8.63 (SD) years; 56.7% were female and 90.9% white. In an assessment of individual metabolic risk factors, adjusted for age, sex, race, and smoking status, increased body mass index (BMI; overweight or obese vs. normal BMI of <25 kg/m2) was associated with an increased odds for new onset of colon APs (P trend < 0.001) as was a diagnosis of diabetes [adjusted conditional OR (aCOR) = 1.59 (1.10-2.29)]. No associations were seen between the metabolic risk factors and onset of SSPs. Being obese or hypertensive each increased the odds of new onset of synch polyps with aCOR values of 2.09 (1.01-4.32) and 1.79 (1.06-3.02), respectively. Self-reported risk factors may help assess polyp type risk. Because SSPs and synch polyps are rare, larger studies are needed to improve our understanding of the contribution of these factors to polyp risk. These data lead us to hypothesize that differences in observed metabolic risk factors between polyp types reflect select metabolic impact on pathways to colorectal cancer. PREVENTION RELEVANCE: Self-reported medical history provides valuable insight into polyp risk, potentially enabling the use of larger retrospective studies of colonoscopy populations to assess knowledge gaps. More aggressive colonoscopy screening, critical to colorectal cancer prevention, may be considered in populations of individuals with metabolic risk factors and modifiable lifestyle risk factors.

Gastrointestinal cancers in China, the USA, and Europe

Gastrointestinal (GI) cancers, including colorectal cancer, gastric cancer, and esophageal cancer, are a major medical and economic burden worldwide and have the largest number of new cancer cases and cancer deaths each year. Esophageal and gastric cancers are most common in developing countries, while colorectal cancer forms the major GI malignancy in Western countries. However, a great shift in the predominant GI-cancer type is happening in countries under economically transitioning and, at the same time, esophageal and gastric cancers are reigniting in Western countries due to the higher exposure to certain risk factors. The development of all GI cancers is highly associated with lifestyle habits and all can be detected by identified precancerous diseases. Thus, they are all suitable for cancer screening. Here, we review the epidemiological status of GI cancers in China, the USA, and Europe; the major risk factors and their distribution in these regions; and the current screening strategies.

Field carcinogenesis for risk stratification of colorectal cancer

Colorectal cancer (CRC) is characterized by genetic-environmental interplay leading to diffuse changes in the entire colonic mucosa (field carcinogenesis or field of injury) and to a pro-neoplastic genetic/epigenetic/physiological milieu. The clinical consequences are increased risk of synchronous and metachronous neoplasia. Factors such as genetics, race, ethnicity, age, and socioeconomic status are thought to influence neoplasia development. Here, we explore the potential improvement to CRC screening through exploiting field carcinogenesis, with particular focus on racial disparities and chemoprevention strategies. Also, we discuss future directions for field carcinogenesis/risk stratification using molecular and novel biophotonic techniques for personalized CRC screening.

Colorectal Cancer and Diet: Risk Versus Prevention, Is Diet an Intervention?

Colorectal cancer is the third most common cause of cancer in men and women in the world. Epidemiologic research approximates that half of colon cancer risk is preventable by modifiable risk factors, including diet. This article reviews prior studies involving certain food items and their relation to colorectal cancer, to elucidate whether diet can be a potential intervention.

Healthy lifestyle, endoscopic screening, and colorectal cancer incidence and mortality in the United States: A nationwide cohort study

BACKGROUND

Healthy lifestyle and screening represent 2 major approaches to colorectal cancer (CRC) prevention. It remains unknown whether the CRC-preventive benefit of healthy lifestyle differs by endoscopic screening status, and how the combination of healthy lifestyle with endoscopic screening can improve CRC prevention.

METHODS AND FINDINGS

We assessed lifestyle and endoscopic screening biennially among 75,873 women (Nurses' Health Study, 1988 to 2014) and 42,875 men (Health Professionals Follow-up Study, 1988 to 2014). We defined a healthy lifestyle score based on body mass index, smoking, physical activity, alcohol consumption, and diet. We calculated hazard ratios (HRs) and population-attributable risks (PARs) for CRC incidence and mortality in relation to healthy lifestyle score according to endoscopic screening. Participants' mean age (standard deviation) at baseline was 54 (8) years. During a median of 26 years (2,827,088 person-years) follow-up, we documented 2,836 incident CRC cases and 1,013 CRC deaths. We found a similar association between healthy lifestyle score and lower CRC incidence among individuals with and without endoscopic screening, with the multivariable HR per one-unit increment of 0.85 (95% CI, 0.80 to 0.90) and 0.85 (95% CI, 0.81 to 0.88), respectively (P-interaction = 0.99). The fraction of CRC cases that might be prevented (PAR) by endoscopic screening alone was 32% (95% CI, 31% to 33%) and increased to 61% (95% CI, 42% to 75%) when combined with healthy lifestyle (score = 5). The corresponding PAR (95% CI) increased from 15% (13% to 16%) to 51% (17% to 74%) for proximal colon cancer and from 47% (45% to 50%) to 75% (61% to 84%) for distal CRC. Results were similar for CRC mortality. A limitation of our study is that our study participants are all health professionals and predominantly whites, which may not be representative of the general population.

CONCLUSIONS

Our study suggests that healthy lifestyle is associated with lower CRC incidence and mortality independent of endoscopic screening. An integration of healthy lifestyle with endoscopic screening may substantially enhance prevention for CRC, particularly for proximal colon cancer, compared to endoscopic screening alone.

Epigenetic Aging and Colorectal Cancer: State of the Art and Perspectives for Future Research

Although translational research has identified a large number of potential biomarkers involved in colorectal cancer (CRC) carcinogenesis, a better understanding of the molecular pathways associated with biological aging in colorectal cells and tissues is needed. Here, we aim to summarize the state of the art about the role of age acceleration, defined as the difference between epigenetic age and chronological age, in the development and progression of CRC. Some studies have shown that accelerated biological aging is positively associated with the risk of cancer and death in general. In line with these findings, other studies have shown how the assessment of epigenetic age in people at risk for CRC could be helpful for monitoring the molecular response to preventive interventions. Moreover, it would be interesting to investigate whether aberrant epigenetic aging could help identify CRC patients with a high risk of recurrence and a worst prognosis, as well as those who respond poorly to treatment. Yet, the application of this novel concept is still in its infancy, and further research should be encouraged in anticipation of future applications in clinical practice.

The Mechanism of Bacteroides fragilis Toxin Contributes to Colon Cancer Formation

The Bacteroides fragilis (B. fragilis) produce biofilm for colonisation in the intestinal tract can cause a series of inflammatory reactions due to B. fragilis toxin (BFT) which can lead to chronic intestinal inflammation and tissue injury and play a crucial role leading to colorectal cancer (CRC). The enterotoxigenic B. fragilis (ETBF) forms biofilm and produce toxin and play a role in CRC, whereas the non-toxigenic B. fragilis (NTBF) does not produce toxin. The ETBF triggers the expression of cyclooxygenase (COX)-2 that releases PGE2 for inducing inflammation and control cell proliferation. From chronic intestinal inflammation to cancer development, it involves signal transducers and activators of transcription (STAT)3 activation. STAT3 activates by the interaction between epithelial cells and BFT. Thus, regulatory T-cell (Tregs) will activates and reduce interleukin (IL)-2 amount. As the level of IL-2 drops, T-helper (T_h17) cells are generated leading to increase in IL-17 levels. IL-17 is implicated in early intestinal inflammation and promotes cancer cell survival and proliferation and consequently triggers IL-6 production that activate STAT3 pathway. Additionally, BFT degrades E-cadherin, hence alteration of signalling pathways can upregulate spermine oxidase leading to cell morphology and promote carcinogenesis and irreversible DNA damage. Patient with familial adenomatous polyposis (FAP) disease displays a high level of tumour load in the colon. This disease is caused by germline mutation of the adenomatous polyposis coli (APC) gene that increases bacterial adherence to the mucosa layer. Mutated-APC gene genotype with ETBF increases the chances of CRC development. Therefore, the colonisation of the ETBF in the intestinal tract depicts tumour aetiology can result in risk of hostility and effect on human health.

Vitamin D supplementation reduces the occurrence of colorectal polyps in high-latitude locations

There is suggestive evidence for the role of vitamin D in the development of colorectal cancer (CRC). Due to high latitudes in Canada, many Canadians are vitamin D deficient throughout winter. In this analysis, we examined the association between vitamin D supplement use and high-risk adenomatous polyps (HRAPs). The study population was drawn from the biorepository at the Forzani & MacPhail Colon Cancer Screening Centre (CCSC) in Calgary. Individuals enrolled between 2013 and 2016 between the age of 50 and 74 years (n = 1409) were included. When examining the association between any supplemental vitamin D use and HRAPs, a protective effect is observed with an OR_adj of 0.57 (95% CI: 0.33-0.96). Similarly, meeting the recommended daily intake (RDI) of vitamin D (600 IU) is protective against HRAPs with an OR_adj of 0.78 (95% CI: 0.62-0.99). This study suggests that adequate vitamin D supplementation reduces the occurrence of colorectal polyps in high-latitude locations.

Prospective Association of Energy Balance Scores Based on Metabolic Biomarkers with Colorectal Cancer Risk

BACKGROUND

Energy balance-related factors, such as body mass index (BMI), diet, and physical activity, may influence colorectal cancer etiology through interconnected metabolic pathways, but their combined influence is less clear.

METHODS

We used reduced rank regression to derive three energy balance scores that associate lifestyle factors with combinations of prediagnostic, circulating levels of high-sensitivity C-reactive protein (hsCRP), C-peptide, and hemoglobin A_1c (HbA_1c) among 2,498 participants in the Cancer Prevention Study-II Nutrition Cohort. Among 114,989 participants, we verified 2,228 colorectal cancer cases. We assessed associations of each score with colorectal cancer incidence and by tumor molecular phenotypes using Cox proportional hazards regression.

RESULTS

The derived scores comprised BMI, physical activity, screen time, and 14 food groups, and explained 5.1% to 10.5% of the variation in biomarkers. The HR and 95% confidence interval (CI) for quartile 4 versus 1 of the HbA_1c+C peptide-based score and colorectal cancer was 1.30 (1.15-1.47), the hsCRP-based score was 1.35 (1.19-1.53), and the hsCRP, C-peptide, and HbA_1c-based score was 1.35 (1.19-1.52). The latter score was associated with non-CIMP tumors (HR_Q4vsQ1: 1.59; 95% CI: 1.17-2.16), but not CIMP-positive tumors (P _{heterogeneity} = 0.04).

CONCLUSIONS

These results further support hypotheses that systemic biomarkers of metabolic health-inflammation and abnormal glucose homeostasis-mediate part of the relationship between several energy balance-related modifiable factors and colorectal cancer risk.

IMPACT

Results support cancer prevention guidelines for maintaining a healthful body weight, consuming a healthful diet, and being physically active. More research is needed on these clusters of exposures with molecular phenotypes of tumors.

Revisiting the impact of lifestyle on colorectal cancer risk in a gender perspective

Colorectal cancer (CRC) is a leading cause of cancer-related mortality in the world. Patterns and trends in CRC incidence and mortality correlate with increasing adoption of Western lifestyles and with the overweight/obesity epidemic. Both genetic background and a range of modifiable environmental/lifestyle factors play a role in CRC etiology. Among these the links of body weight, dietary patterns and physical activity (PA) behavior with CRC risk are some of the strongest for any type of cancer, with a different impact in women and men. Nonetheless, gender disparities still represent a neglected aspect of CRC management. This review sheds light on gender-related association of obesity and different dietary/PA habits with CRC risk, highlighting the importance of lifestyle modifications in the prevention of this neoplastic disease. In this scenario, intervention studies are strongly recommended to define the most effective dietary/PA regimens for primary prevention of cancer in women and men.

Probiotic supplementation attenuates the aggressiveness of chemically induced colorectal tumor in rats

To evaluate the effect of a probiotic on the aggressiveness of a chemically induced colorectal tumor in rats. Twenty-five male Fisher 344 rats, 250 g, provided with feed and water ad libitum, were randomly divided into 5 groups (5 rats/group): G_Control, no treatment; G_Tumor, tumor induction; G_Tumor+5FU, tumor induction, 5-Fluorouracil applied; G_Tumor+Prob, induction of the tumor, supplemented with probiotic; G_{Tumor+5-FU+Prob}, tumor induction, 5-Fluorouracil applied, supplemented with probiotic. For tumor induction 20 mg/kg of 1,2-dimethylhydrazine was applied intraperitoneally over 4 weeks, followed by an interval of 15 days, and then repeated for a further 4 weeks. Five weeks after the final dose of the carcinogen, treatment was initiated with 5-Fluorouracil (15 mg/kg, intraperitoneally/week) and a commercial probiotic (1 × 10⁹ CFU, daily/gavage). Data were analyzed by One Way Variance Analysis and means compared by Dunnett's test. GraphPad Prism statistical software was used. The histopathological analyzes were evaluated by the chi-square test. A 5% type-I error was considered statistically significant. Compared with the G_Tumor, the G_Tumor+Prob (p < 0.0373) and G_{Tumor+5-FU+Prob} (p < 0.0003) demonstrated an attenuated effect on the aggressiveness of the colorectal tumor, with a reduction in the count of Aberrant Crypt foci; and a lower percentage of malignant neoplastic lesions in the G_Tumor+Prob (40% low grade tubular adenoma, 40% carcinoma in situ, 20% low grade adenocarcinoma) and G_{Tumor+5-FU+Prob} (40% low grade tubular adenoma and 60% carcinoma in situ). Probiotic supplementation has the potential to decrease the formation of aberrant crypts and ameliorate tumor malignancy, enhancing the antitumor effect of 5-Fluorouracil chemotherapy in colic segments.

Physical Activity and Gastrointestinal Cancer Risk: A Review

Introduction: Western lifestyle characterized by increased consumption of red meat, fat, processed food, smoking, alcohol drinking, lower consumption of vegetables and physical inactivity has been associated with a higher gastrointestinal cancer risk. Digestive system cancers are diagnosed at late stages when they show poor response to treatment and are associated with a high mortality rate. Colorectal, gastric, esophageal and pancreatic cancers are among the most common cancers worldwide. Studies show that more than 50% of gastrointestinal cancers develop as a result of inappropriate lifestyle. An inverse association between physical activity and many chronic diseases has been proved so far. However, the association between physical activity and some gastrointestinal cancers is still controversial. This study was aimed to determine the association between physical activity and gastrointestinal cancers risk.

Methods: We conducted a comprehensive search of English and Persian databases from February 2007 till December 2017, for studies investigating the association of physical activity and risk of gastrointestinal cancers. Finally, after reading full text of articles, 123 studies were included.

Results: Physical activity can be helpful in reducing the risk of gastrointestinal cancer, especially colon and pancreatic cancers. The risk reduction is not similar for different types of gastrointestinal cancers and also among males and females.

Conclusion: Different types of physical activity are associated with a lower risk of gastrointestinal cancer. However, it is unknown which type and intensity of physical activity are associated with a protective effect against gastro-intestinal cancer.

Screening in spouses of colorectal cancer patients: a missed opportunity

BACKGROUND

Spouses of colorectal cancer (CRC) patients could be at increased risk of developing CRC due to shared lifestyle habits with the patients which is a notable risk factor. This study explores the various issues surrounding CRC screening among these spouses.

METHODS

A mixed method study comprising in-depth qualitative semi-structured interviews followed by structured quantitative questionnaire was administered to spouses who accompanied CRC patients during their appointments, from January 2016 to February 2017.

RESULTS

Fifty spouses of CRC patients, median age of 60 (range, 41-82) years, were qualitatively interviewed but 5 of them did not complete the questionnaire. Only 26 (57.8%) of them were current with CRC screening. Data saturation was reached at the 48th participant. Four main themes emerged from the qualitative interviews. These included (i) adequacy of knowledge and attitudes about CRC screening, (ii) suboptimal public health promotion efforts of CRC screening, (iii) barriers of CRC screening, and (iv) need for mutual spousal support. From the questionnaires, spouses who were not current with CRC screening were more likely to report more barriers and have different cues to actions than those who are current. The majority of the spouses demonstrated high levels of knowledge on CRC, understood its severity and their susceptibility.

CONCLUSION

Spouses exhibit high levels of knowledge and awareness of the implications of CRC. Apart from addressing psychological issues during the acute phases, targeted interventions should be considered to improve their screening rates and to use them as advocates for CRC screening among family and community.

Healthy living and cancer: evidence from UK Biobank

CONTEXT

UK Biobank is a prospective study of half a million subjects, almost all aged 40-69 years, identified in 22 centres across the UK during 2006-2010.

OBJECTIVE

A healthy lifestyle has been described as 'better than any pill, and no side effects [5]. We therefore examined the relationships between healthy behaviours: low alcohol intake, non-smoking, healthy BMI, physical activity and a healthy diet, and the risk of all cancers, colon, breast and prostate cancers in a large dataset.

METHOD

Data on lifestyle behaviours were provided by 343,150 subjects, and height and weight were measured at recruitment. 14,285 subjects were diagnosed with cancer during a median of 5.1 years of follow-up.

RESULTS

Compared with subjects who followed none or a single healthy behaviour, a healthy lifestyle based on all five behaviours was associated with a reduction of about one-third in incident cancer (hazard ratio [HR] 0.68; 95% confidence intervals [CI] 0.63-0.74). Colorectal cancer was reduced in subjects following the five behaviours by about one-quarter (HR 0.75; 95% CI 0.58-0.97), and breast cancer by about one-third (HR 0.65; 95% CI 0.52-0.83). The association between a healthy lifestyle and prostate cancer suggested a significant increase in risk, but this can be attributed to bias consequent on inequalities in the uptake of the prostate specific antigen screening test.

CONCLUSIONS

Taken together with reported reductions in diabetes, vascular disease and dementia, it is clearly important that every effort is taken to promote healthy lifestyles throughout the population, and it is pointed out that cancer and other screening clinics afford 'teachable moments' for the promotion of a healthy lifestyle.

Recent advances in the link between physical activity, sedentary behavior, physical fitness, and colorectal cancer

Physical inactivity is a well-established risk factor for colorectal cancer (CRC). Recent studies have characterized physical activity (PA), sedentary behavior, and cardiorespiratory fitness as distinct, interrelated constructs that influence the risk of CRC and related outcomes. PA levels required to confer protection against CRC may be higher than previously thought. Sedentary behavior, defined as time spent sitting, increases CRC risk independent of PA and may require novel interventions distinct from those targeting PA. Finally, cardiorespiratory fitness is inversely associated with CRC risk and mortality and may provide a potential tool for risk stratification and intervention.

Colorectal Cancer Epidemiology in the Nurses' Health Study

OBJECTIVES

To review the contribution of the Nurses' Health Study (NHS) to identifying risk and protective factors for colorectal adenomas and colorectal cancer (CRC).

METHODS

We performed a narrative review of the publications using the NHS between 1976 and 2016.

RESULTS

Existing epidemiological studies using the NHS have reported that red and processed meat, alcohol, smoking, and obesity were associated with an increased risk of CRC, whereas folate, calcium, vitamin D, aspirin, and physical activity were associated with decreased risk of CRC. Moreover, modifiable factors, such as physical activity, vitamin D, folate, insulin and insulin-like growth factor binding protein-1, and diet quality, were identified to be associated with survival among CRC patients. In recent years, molecular pathological epidemiological studies have been actively conducted and have shown refined results by molecular subtypes of CRC.

CONCLUSIONS

The NHS has provided new insights into colorectal adenomas, CRC etiology, and pathogenic mechanisms. With its unique strengths, the NHS should continue to contribute to the field of CRC epidemiology and play a major role in public health.

Smoking and alcohol behaviours in people following hip and knee arthroplasty: Data from the Osteoarthritis Initiative

BACKGROUND

Smoking and alcohol consumption has a negative effect on overall health. Limited evidence has been presented as to how these health behaviours may change between pre- and postoperative intervals in the initial 12 months post-arthroplasty. The purpose of this study was to address this uncertainty.

HYPOTHESIS

Smoking and alcohol consumption differs between pre- and post-THA/TKA and it differs between non-arthroplasty cohorts.

MATERIALS AND METHODS

Data from the Osteoarthritis Initiative (OAI), a population-based observational study in the USA, were gathered. In total, data from 287 people who had undergone THA or TKA from baseline to month 48 OAI follow-up assessments were analysed. Data on this cohort were compared to 287 age- and gender-matched people with osteoarthritis. Mean change from pre- to post-arthroplasty, and differences between arthroplasty and non-arthroplasty participants for smoking and alcohol consumption were assessed descriptively and through Wilcoxin-matched pairs test and Student t-tests (as appropriate).

RESULTS

The lifetime prevalence of smoking was high for people who received THA (99%) and TKA (96%). Prevalence of current smoking significantly decreased from 5 to 3% across the THA and TKA cohort in the initial 12 months post-arthroplasty (P<0.05). Similarly, there was a statistically significant decrease in weekly alcohol consumption post-arthroplasty for people who underwent THA and TKA (P<0.01), although the mean difference was only by 0.9 alcoholic drinks. The only statistically significant difference in smoking and alcohol consumption for arthroplasty to non-arthroplasty participants was in weekly alcohol consumption, which was higher by 0.3 drinks in the non-arthroplasty cohort (P=0.04).

CONCLUSIONS

Smoking and alcohol consumption decreased in the initial 12 months post-THA and TKA. This was not significantly different to an age- and gender-matched non-arthroplasty cohort. Whilst this is positive, a small group of patients still present with unhealthy lifestyle choices in relation to these behaviours post-arthroplasty.

LEVEL OF EVIDENCE

Level III - prospective case control study.

Impacts of Physical Activity on the Obese

Approximately two-thirds of the US population is overweight or obese. Physical activity is recommended for preventing obesity, aiding in weight loss, and decreasing rates of chronic diseases. This article reviews current statistics for obesity, physical activity, and physician counseling patterns. Principles of exercise physiology relating to cardiopulmonary fitness and chronic disease are also reviewed and methods for increasing physical activity in adults and children are suggested.

Colorectal cancer

Colorectal cancer had a low incidence several decades ago. However, it has become a predominant cancer and now accounts for approximately 10% of cancer-related mortality in western countries. The 'rise' of colorectal cancer in developed countries can be attributed to the increasingly ageing population, unfavourable modern dietary habits and an increase in risk factors, such as smoking, low physical exercise and obesity. New treatments for primary and metastatic colorectal cancer have emerged, providing additional options for patients; these treatments include laparoscopic surgery for primary disease, more-aggressive resection of metastatic disease (such as liver and pulmonary metastases), radiotherapy for rectal cancer, and neoadjuvant and palliative chemotherapies. However, these new treatment options have had limited impact on cure rates and long-term survival. For these reasons, and the recognition that colorectal cancer is long preceded by a polypoid precursor, screening programmes have gained momentum. This Primer provides an overview of the current state of the art of knowledge on the epidemiology and mechanisms of colorectal cancer, as well as on diagnosis and treatment.