Colorectal polyp prevention by daily aspirin use is abrogated among active smokers

Zero-inflated models for the evaluation of colorectal polyps in colon cancer screening studies-a value-based biostatistics practice

Background

Colon cancer screening studies are needed for the early detection of colorectal polyps to reduce the risk of colorectal cancer. Unfortunately, the data generated on colon polyps are typically analyzed in their dichotomized form and sometimes with standard count models, which leads to potentially inaccurate findings in research studies. A more appropriate approach for evaluating colon polyps is zero-inflated models, considering undetected existing polyps at colonoscopy screening.

Method

We demonstrated the application of the zero-inflated and hurdle models including zero-inflated Poisson (ZIP), zero-inflated robust Poisson (ZIRP), zero-inflated negative binomial (ZINB), zero-inflated generalized Poisson (ZIGP), zero hurdle Poisson (ZHP), and zero hurdle negative binomial (ZHNB) models, and compared them with standard approaches including logistic regression (LR), Poisson regression (PR), robust Poisson (RP), and negative binomial (NB) regression for the evaluation of colorectal polyps using datasets from two randomized studies and one observational study. We also facilitated a step-by-step approach for selecting appropriate models for analyzing polyp data.

Results

All datasets yielded a significant amount of no polyps and therefore inflated or hurdle models performed best over single distribution models. We showed that cap-assisted colonoscopy yielded significantly more colon polyps (risk ratio [RR] = 1.38; 95% confidence interval [CI] [1.05-1.81]) compared with the standard colonoscopy by using the ZIP analysis. However, these findings were missed by standard analytic methods, including LR (odds ratio [OR] = 0.90; 95% CI [0.59-1.37]), PR (RR = 1.14; 95% CI [0.93-1.41]), and NB (RR = 1.16; 95% CI [0.89-1.51]) for evaluating colon polyps. The standard approaches, such as LR, PR, RP, or NB regressions for analyzing polyp data, produced potentially inaccurate findings compared to zero-inflated models in all example datasets. Furthermore, simulation studies also confirmed the superiority of ZIRP over alternative models in a range of datasets differing from the case studies. ZIRP was found to be the optimal method for analyzing polyp data in randomized studies, while the ZINB/ZHNB model showed a better fit in an observational study.

Conclusion

We suggest colonoscopy studies should jointly use the polyp detection rate and polyp counts as the quality measure. Based on theoretical, empirical, and simulation considerations, we encourage analysts to utilize zero-inflated models for evaluating colorectal polyps in colonoscopy screening studies for proper clinical interpretation of data and accurate reporting of findings. A similar approach can also be used for analyzing other types of polyp counts in colonoscopy studies.

Review of Network Meta-Analyses on the Efficacy of Chemopreventive Agents on Colorectal Adenomas and Cancer

BackgroundColorectal cancer (CRC) is the third most diagnosed cancer and the second leading cause of cancer-related death worldwide. Colorectal adenomas (CRAs) are a crucial precursor for CRC and a target for preventive strategies. Recent network meta-analyses (NMAs) of randomized controlled trials (RCTs) suggest that chemopreventive agents (CPAs) are associated with reductions in CRC incidence. However, the quality of this evidence is low due to significant variability in the methods and types of studies assessed.PurposeOur study reviewed the efficacy and safety of CPAs on CRAs or CRCs evaluated in NMAs of RCTs and assessed the quality of all published NMAs on CPAs.Research DesignWe searched PubMed, Embase, and Cochrane Library for studies published from inception to July 29, 2024. We included all NMAs assessing the efficacy and safety of CPAs on CRC in both average-risk (general population) and high-risk (previous history of adenoma/CRC) populations. ResultsNine NMAs comparing 15 different interventions were included. Aspirin and non-aspirin non-steroidal anti-inflammatory drugs (NSAIDs) such as celecoxib were the most studied. Aspirin demonstrated efficacy against the development of any CRA and low-dose aspirin was consistently more protective than high-dose aspirin. However, the effect of aspirin against advanced CRA was not statistically significant. Concerns for long-term aspirin use included an increased risk of gastrointestinal bleeding and ulceration, but when evaluating all serious adverse events (SAEs), aspirin users did not have an increased risk compared to controls. Non-aspirin NSAIDs showed better efficacy against advanced CRA. However, the use of non-aspirin NSAIDs such as celecoxib was associated with significantly increased risk of SAEs, particularly cardiovascular disease events.ConclusionsConsidering the balance of efficacy and safety, low-dose aspirin is currently the best option for chemoprevention of CRA/CRC. Future research is needed to better characterize the patient subgroups that benefit most and to develop new, more effective CPAs.

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.

Colorectal Cancer Chemoprevention: A Dream Coming True?

Colorectal cancer (CRC) is one of the deadliest forms of cancer worldwide. CRC development occurs mainly through the adenoma-carcinoma sequence, which can last decades, giving the opportunity for primary prevention and early detection. CRC prevention involves different approaches, ranging from fecal occult blood testing and colonoscopy screening to chemoprevention. In this review, we discuss the main findings gathered in the field of CRC chemoprevention, focusing on different target populations and on various precancerous lesions that can be used as efficacy evaluation endpoints for chemoprevention. The ideal chemopreventive agent should be well tolerated and easy to administer, with low side effects. Moreover, it should be readily available at a low cost. These properties are crucial because these compounds are meant to be used for a long time in populations with different CRC risk profiles. Several agents have been investigated so far, some of which are currently used in clinical practice. However, further investigation is needed to devise a comprehensive and effective chemoprevention strategy for CRC.

Aspirin-Mediated Prevention of Colorectal Adenomas Recurrence is Affected by Blood Biochemistry and Nutritional Intake

Aspirin has been shown to prevent the onset of colorectal adenoma and cancer. This study aimed to identify patient characteristics and blood chemistry factors related to the effect of aspirin. A total of 231 men and 59 women who participated in our previous randomized clinical study in 2007-2009 using aspirin or placebo (J-CAPP study) were analyzed. Interaction of aspirin with age at entry, body mass index (BMI), alcohol intake, blood biochemistry, and nutrients calculated from a semiquantitative food frequency questionnaire were analyzed on the basis of the presence of adenomas 2 years later. Our study showed that suppression of adenoma by aspirin was not affected by age or BMI. Among men, significant suppression of adenoma by aspirin was seen with triglyceride (TG) <167 mg/dL (P = 0.02), total cholesterol (T-cho) ≥220 mg/dL (P = 0.01), high-density lipoprotein (HDL) ≥60 mg/dL (P < 0.01), and low-density lipoprotein (LDL) ≥140 mg/dL (P = 0.01), aspartate aminotransferase (AST) <30 IU/L (P = 0.01), alanine aminotransferase <30 IU/L (P = 0.04), and gamma-glutamyl transpeptidase <60 IU/L (P = 0.04). In addition, the interaction was significant with TG ≥/<167 mg/dL (P = 0.02), T-cho ≥/<220 mg/dL (P = 0.03), HDL ≥/<60 mg/dL (P = 0.02), LDL ≥/<140 mg/dL (P = 0.03), and AST ≥/<30 IU/L (P = 0.01). Daily nutrient intake associated with aspirin was <2,000 mg sodium (P = 0.06) and ≥850 μg retinol equivalent (P = 0.05) among men, indicating a marginal effect on adenoma suppression. No significant differences were detected among women due to the small sample size. In conclusion, lipid metabolism and liver function were correlated with the suppressive effect of aspirin on the recurrence of colorectal adenoma.

PREVENTION RELEVANCE

Aspirin has been shown to prevent the onset of colorectal adenoma and cancer, and its effect modifications have been analyzed. Lipid metabolism and liver function were correlated with the suppressive effect of aspirin on the recurrence of colorectal adenoma.

Body Mass Index, sex, non-steroidal anti-inflammatory drug medications, smoking and alcohol are differentially associated with World Health Organisation criteria and colorectal cancer risk in people with Serrated Polyposis Syndrome: an Australian case-control study

OBJECTIVE

The unknown aetiology of Serrated Polyposis Syndrome (SPS) impedes risk prediction and prevention. We investigated risk factors for SPS, overall and stratified by World Health Organization (WHO)²⁰¹⁰ clinical criteria and by colorectal cancer (CRC).

METHOD

A retrospective case-control study involving a cross-sectional analysis from 350 unrelated individuals with SPS from the Genetics of Colonic Polyposis Study and 714 controls from the Australasian Colorectal Cancer Family Registry. Univariate and multivariate logistic regression modelling was used to determine the association between risk factors and SPS and risk factors associated with CRC in SPS.

RESULTS

Female biological sex (odds ratio (OR) = 4.54; 95%Confidence interval (CI) = 2.77-7.45), increasing body mass index (BMI) at age 20 years (OR = 1.09; 95%CI = 1.04-1.13), hormone replacement therapy (OR = 0.44; 95%CI = 0.20.98), and increasing weekly folate intake (OR = 0.82; 95%CI = 0.75-0.90) were associated with SPS by multivariate analysis. Increasing weekly calcium intake (OR = 0.79; 95%CI = 0.64-0.97) and smoking > 10 cigarettes daily (OR = 0.45; 95%CI = 0.23-0.86) were associated with WHO criterion I only. The consumption of 1-100 g of alcohol per week (OR = 0.39; 95%CI = 0.18-0.83) was associated with WHO criterion III only. Smoking 1-5 cigarettes daily (OR = 2.35; 95%CI = 1.09-5.05), weekly non-steroidal anti-inflammatory drug (NSAIDs) intake (OR = 0.88; 95%CI = 0.78-0.99), and increased height (OR = 1.09; 95% = 1.05-1.13), were associated with SPS fulfilling both WHO criteria I and III. Moreover, weekly NSAIDs intake (OR = 0.81; 95%CI = 0.67-0.98) was associated with a reduced likelihood of CRC in SPS.

CONCLUSION

We identified novel risk and potential protective factors associated with SPS, some specific for certain WHO²⁰¹⁰ criteria. Weekly use of NSAIDs may reduce the risk of CRC in people with SPS.

Effects of polymorphic cytochrome P450 2A6 genotypes on chemoprevention against colorectal tumors in single Japanese cohort using daily low-dose aspirin: insights into future personalized treatments

BACKGROUND

A chemopreventive effect of low-dose aspirin against colorectal tumors was previously found in participants of two Japanese multicenter, double-blind, randomized, placebo-controlled clinical trials investigating the effects of daily aspirin (100 mg/day) for 0.7-2 years on tumor recurrence in colorectal cancer patients whose tumors were excised endoscopically.

METHODS

In the current study, chemopreventive data from single-center subsets having daily aspirin (100 mg/day) were reanalyzed with respect to variations in polymorphic cytochrome P450 2A6 (CYP2A6). From the J-CAPP study, 56 of 311 participants (47 men, 9 women; excluding patients with familial adenomatous polyposis) were genotyped for CYP2A6*1, *4 (whole-gene deletion), *7 (amino acid substitution), and *9 (upstream mutation), and from the J-FAPP IV study, 81 of 102 participants (43 men, 38 women; including patients with familial adenomatous polyposis) were also genotyped.

RESULTS

The chemopreventive effects of daily aspirin were found to be inversely dependent on the predicted enzyme activity of the CYP2A6 phenotype [based on normal genotypes (CYP2A6*1/*1,*7,*9) and impaired genotypes (CYP2A6*4,*7,*9/*4,*7,*9 and CYP2A6*1/*4)] among a nonsmoker Japanese cohort without familial adenomatous polyposis.

CONCLUSIONS

The CYP2A6 wild-type allele could be a candidate biomarker for reduced chemopreventive effects of daily aspirin in a population with wide-ranging CYP2A6 phenotypes with a high frequency of impaired activities resulting from variations and whole-gene deletions. The CYP2A6 genotypes could be applicable to future personalized treatments for colorectal tumor chemoprevention with daily aspirin.

Assessment of the cytotoxic, genotoxic, and apoptotic potential of flurbiprofen in HeLa and HepG2 cell lines

In the literature, the anticancer potential of flurbiprofen isn't fully understood. In this study, the cytotoxic, genotoxic, and apoptotic effects of flurbiprofen were evaluated in human cervical and liver cancer cells. Cytotoxicity was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and it was observed that cytotoxicity increased in a concentration- and time-dependent manner. Genotoxicity was determined using alkaline Comet assay. DNA damage increased in a concentration-dependent manner. Early apoptosis was evaluated using real-time polymerase chain reaction, and it was found that apoptotic gene levels increased while antiapoptotic gene levels decreased. Late apoptosis and cell cycle analyzes were determined using flow cytometry. No evidence of late apoptosis was observed, and no significant arrest was found in the cell cycle. In conclusion, it seems that flurbiprofen has a cytotoxic, genotoxic, and apoptotic effects in both human cancer cell lines. Moreover, the findings indicate that flurbiprofen is effective at the gene level and induces apoptosis with an intracellular pathway.

Aspirin in the Prevention of Colorectal Neoplasia

High-quality evidence indicates that regular use of aspirin is effective in reducing the risk for precancerous colorectal neoplasia and colorectal cancer (CRC). This has led to US and international guidelines recommending aspirin for the primary prevention of CRC in specific populations. In this review, we summarize key questions that require addressing prior to broader adoption of aspirin-based chemoprevention, review recent evidence related to the benefits and harms of aspirin use among specific populations, and offer a rationale for precision prevention approaches. We specifically consider the mechanistic implications of evidence showing differences in aspirin's effects according to age, the potential role of modifiable mechanistic biomarkers for personalizing prevention, and emerging evidence that the gut microbiota may offer novel aspirin-associated preventive targets to reduce high-risk neoplasia.

Chemoprevention of Colorectal Cancer

Although colorectal cancer (CRC) screening has reduced the incidence of and mortality from CRC, chemoprevention strategies have the potential to further reduce CRC incidence and mortality. Chemoprevention agents might be used for average-risk as well as high-risk groups, and to prevent CRC recurrence after therapy. CRC chemoprevention agents that have been studied include aspirin, nonaspirin nonsteroidal anti-inflammatory drugs, statins, agents that target metabolic pathways, and vitamins and minerals. We review the prospect of chemoprevention of CRC, results from preclinical and human studies, challenges, and future directions.

Influence of Smoking, Body Mass Index, and Other Factors on the Preventive Effect of Nonsteroidal Anti-Inflammatory Drugs on Colorectal Cancer Risk

Nonsteroidal anti-inflammatory drugs' (NSAID) use has consistently been associated with lower risk of colorectal cancer; however, studies showed inconsistent results on which cohort of individuals may benefit most. We performed multivariable logistic regression analysis to systematically test for the interaction between regular use of NSAIDs and other lifestyle and dietary factors on colorectal cancer risk among 11,894 cases and 15,999 controls. Fixed-effects meta-analyses were used for stratified analyses across studies for each risk factor and to summarize the estimates from interactions. Regular use of any NSAID, aspirin, or nonaspirin NSAIDs was significantly associated with a lower risk of colorectal cancer within almost all subgroups. However, smoking status and BMI were found to modify the NSAID-colorectal cancer association. Aspirin use was associated with a 29% lower colorectal cancer risk among never-smokers [odds ratios (OR) = 0.71; 95% confidence intervals (CI): 0.64-0.79], compared with 19% and 17% lower colorectal cancer risk among smokers of pack-years below median (OR, 0.81; 95% CI, 0.71-0.92) and above median (OR, 0.83; 95% CI, 0.74-0.94), respectively (P interaction = 0.048). The association between any NSAID use and colorectal cancer risk was also attenuated with increasing BMI (P interaction = 0.075). Collectively, these results suggest that obese individuals and heavy smokers are unlikely to benefit as much as other groups from the prophylactic effect of aspirin against colorectal cancer.Significance: Obesity and heavy smoking attenuate the benefit of aspirin use for colorectal cancer prevention. Cancer Res; 78(16); 4790-9. ©2018 AACR.

NSAID use and somatic exomic mutations in Barrett's esophagus

Background

Use of aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) has been shown to protect against tetraploidy, aneuploidy, and chromosomal alterations in the metaplastic condition Barrett’s esophagus (BE) and to lower the incidence and mortality of esophageal adenocarcinoma (EA). The esophagus is exposed to both intrinsic and extrinsic mutagens resulting from gastric reflux, chronic inflammation, and exposure to environmental carcinogens such as those found in cigarettes. Here we test the hypothesis that NSAID use inhibits accumulation of point mutations/indels during somatic genomic evolution in BE.

Methods

Whole exome sequences were generated from 82 purified epithelial biopsies and paired blood samples from a cross-sectional study of 41 NSAID users and 41 non-users matched by sex, age, smoking, and continuous time using or not using NSAIDs.

Results

NSAID use reduced overall frequency of point mutations across the spectrum of mutation types, lowered the frequency of mutations even when adjusted for both TP53 mutation and smoking status, and decreased the prevalence of clones with high variant allele frequency. Never smokers who consistently used NSAIDs had fewer point mutations in signature 17, which is commonly found in EA. NSAID users had, on average, a 50% reduction in functional gene mutations in nine cancer-associated pathways and also had less diversity in pathway mutational burden compared to non-users.

Conclusions

These results indicate NSAID use functions to limit overall mutations on which selection can act and supports a model in which specific mutant cell populations survive or expand better in the absence of NSAIDs.

Electronic supplementary material

The online version of this article (10.1186/s13073-018-0520-y) contains supplementary material, which is available to authorized users.

Proximal Aberrant Crypt Foci Associate with Synchronous Neoplasia and Are Primed for Neoplastic Progression

Aberrant crypt foci (ACF) are the earliest morphologically identifiable lesion found within the human colon. Despite their relatively high frequency in the distal colon, few studies have examined the molecular characteristics of ACF within the proximal colon. In the following study, clinical participants (n = 184) were screened for ACF using high-definition chromoendoscopy with contrast dye-spray. Following pathologic confirmation, ACF biopsies were subjected to laser capture microdissection (LCM), and epithelial cells were evaluated for somatic mutations with a customized colorectal cancer mutation panel using DNA-mass spectrometry. Samples were further characterized for microsatellite instability (MSI). Logistic models were used to associate proximal ACF with synchronous (detected during the same procedure) neoplasia. Thirty-nine percent of participants had at least one histologically confirmed proximal ACF. Individuals with a proximal ACF were significantly more likely to present with a synchronous neoplasm (P = 0.001), and specifically, a proximal, tubular, or tubulovillous adenoma (multivariable OR = 2.69; 95% confidence interval, 1.12-6.47; P = 0.027). Proximal ACF were more likely to be dysplastic (52%) compared with distal ACF (13%; P < 0.0001). Somatic mutations to APC, BRAF, KRAS, NRAS, and ERBB2 were detected in 37% of proximal ACF. Hyperplastic ACF were more often MSI-high, but there were no differences in MSI status observed by colonic location. In summary, ACF are identified in the proximal colons of approximately 40% of individuals undergoing chromoendoscopy and more often in patients with synchronous proximal adenomas.Implications: This study provides the most complete set of data, to date, that ACF represent the earliest step in the adenoma-carcinoma sequence but remain below the detection limit of conventional endoscopy.Visual Overview: http//mcr.accrjournals.org/content/molcanres/16/3/486/F1.large.jpg Mol Cancer Res; 16(3); 486-95. ©2017 AACR.

The Role of Alcohol on Antiretroviral Therapy Adherence Among Persons Living With HIV in Urban India

OBJECTIVE

The purpose of this study was to estimate the prevalence of alcohol use among men living with HIV on antiretroviral therapy (ART) and examine the association of alcohol use and psychosocial variables on ART adherence. The study was a cross-sectional survey supplemented by medical records and qualitative narratives as a part of the initial formative stage of a multilevel, multicentric intervention and evaluation project.

METHOD

A screening instrument was administered to men living with HIV (n = 3,088) at four ART Centers using the Alcohol Use Disorders Identification Test-consumption questions (AUDIT-C) to determine alcohol use for study eligibility. Alcohol screening data were triangulated with medical records of men living with HIV (n = 15,747) from 13 ART Centers to estimate alcohol consumption among men on ART in greater Mumbai. A survey instrument to identify associations between ART adherence and alcohol, psychosocial, and contextual factors was administered to eligible men living with HIV (n = 361), and in-depth interviews (n = 55) were conducted to elucidate the ways in which these factors are manifest in men's lives.

RESULTS

Nearly one fifth of men living with HIV on ART in the Mumbai area have consumed alcohol in the last 30 days. Non-adherence was associated with a higher AUDIT score, consumption of more types of alcohol, and poorer self-ratings on quality of life, depression, and external stigma. The qualitative data demonstrate that non-adherence results from avoiding the mixing of alcohol with medication, forgetfulness when drinking, and skipping medication for fear of disclosure of HIV status when drinking with friends.

CONCLUSIONS

As the demand for ART expands, Indian government programs will need to more effectively address alcohol to reduce risk and maintain effective adherence.

A Prospective Study of Smoking and Risk of Synchronous Colorectal Cancers

OBJECTIVES

Cigarette smoking has been linked to somatic genetic and epigenetic aberrations, including CpG island methylator phenotype (CIMP)-high, microsatellite instability (MSI)-high and BRAF mutation. These molecular features have been associated with synchronous primary colorectal cancers (CRCs). Thus, we examined the hypothesis that smoking might be associated with the risk of synchronous CRCs.

METHODS

Within the Health Professionals Follow-up Study and Nurses' Health Study, we examined the relationship of smoking and incidence of CRC according to tumor synchronicity, using duplication-method Cox proportional hazards regression analysis.

RESULTS

We confirmed 1,981 solitary CRC and 45 synchronous CRC cases during follow-up of 134,305 individuals. CRC risk associated with smoking differed significantly by tumor synchronicity status (P_{heterogeneity}<0.001). When comparing current smokers with never smokers, multivariable hazard ratios (HR) were 5.27 (95% confidence interval (CI), 2.08-13.40) for synchronous CRCs and 0.97 (95% CI, 0.83-1.14) for solitary CRC. Similarly, differential associations were observed when examining cumulative pack-years smoked (P_{heterogeneity}=0.006). Smoking cessation for ≥10 years relative to current smoking might reduce the risk of synchronous CRCs (multivariable HR=0.42; 95% CI, 0.19-0.95), but not solitary CRC (multivariable HR=1.10; 95% CI, 0.94-1.29; P_{heterogeneity}=0.001). Comparing current and former smokers with never smokers, multivariable HRs for synchronous CRCs were significantly higher than those of solitary CRC positive for either CIMP-high, MSI-high, or BRAF mutation (P_{heterogeneity}=0.002).

CONCLUSIONS

Smoking is associated with an elevated risk of synchronous CRCs. Our data support a model where smoking contributes to an etiologic field effect that favors these somatic molecular alterations and the development of multiple primary tumors.

Lifestyle Risk Factors for Serrated Colorectal Polyps: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

Certain subsets of colorectal serrated polyps (SP) have malignant potential. We performed a systematic review and meta-analysis to investigate the association between modifiable lifestyle factors and risk for SPs.

METHODS

We conducted a systematic search of Medline, Embase, and Web of Science for observational or interventional studies that contained the terms risk or risk factor, and serrated or hyperplastic, and polyps or adenomas, and colorectal (or synonymous terms), published by March 2016. Titles and abstracts of identified articles were independently reviewed by at least 2 reviewers. Adjusted relative risk (RR) and 95% confidence interval (CI) were combined using random effects meta-analyses to assess the risk of SP, when possible.

RESULTS

We identified 43 studies of SP risk associated with 7 different lifestyle factors: smoking, alcohol, body fatness, diet, physical activity, medication, and hormone-replacement therapy. When we compared the highest and lowest categories of exposure, factors we found to significantly increase risk for SP included tobacco smoking (RR, 2.47; 95% CI, 2.12-2.87), alcohol intake (RR, 1.33; 95% CI, 1.17-1.52), body mass index (RR, 1.40; 95% CI, 1.22-1.61), and high intake of fat or meat. Direct associations for smoking and alcohol, but not body fat, tended to be stronger for sessile serrated adenomas/polyps than hyperplastic polyps. In contrast, factors we found to significantly decrease risks for SP included use of nonsteroidal anti-inflammatory drugs (RR, 0.77; 95% CI, 0.65-0.92) or aspirin (RR, 0.81; 95% CI, 0.67-0.99), as well as high intake of folate, calcium, or fiber. No significant associations were detected between SP risk and physical activity or hormone replacement therapy.

CONCLUSIONS

Several lifestyle factors, most notably smoking and alcohol, are associated with SP risk. These findings enhance our understanding of mechanisms of SP development and indicate that risk of serrated pathway colorectal neoplasms could be reduced with lifestyle changes.

Dietary Methyl Donor Depletion Suppresses Intestinal Adenoma Development

The role of folate one-carbon metabolism in colorectal cancer development is controversial, with nutritional intervention studies producing conflicting results. It has been reported that Apc^Min/+ mice maintained on a diet deficient in the methyl donors folic acid, methionine, choline, and vitamin B12, and supplemented with homocysteine, show a greater than 95% reduction in intestinal tumor development. The present study extends these findings and shows that tumor protection afforded by dietary methyl donor deficiency (MDD) is long-lasting. After 11 weeks of MDD, tumor protection persisted for at least an additional 7 weeks of methyl donor repletion (22.2 ± 3.5 vs. 70.2 ± 4.6 tumors per mouse; P < 0.01). Sustained tumor protection was associated with a reduction in intestinal crypt length (26%, P < 0.01), crypt cell division and crypt fission, and an increase in apoptosis of both normal crypts and tumors (4.9- and 3.2-fold, respectively, P < 0.01). MDD also caused a significant reduction in the number of Dclk1-positive cells in the intestine (62%, P < 0.01), a long-lived crypt cell with cancer stem cell potential. Several undesirable effects associated with methyl donor restriction (e.g., reduced body weight gain) were shown to be transient and readily reversible following methyl donor repletion. Taken together, these results indicate that even temporary dietary methyl donor restriction in adenoma-prone mice can induce persistent changes to the intestinal epithelium and provide long-lasting tumor protection. These data also suggest that transient reductions in dietary methyl donor consumption should be considered when studying the impact of folate on colon cancer risk in humans. Cancer Prev Res; 9(10); 812-20. ©2016 AACR.

Baseline C-reactive protein level predicts survival of early-stage lung cancer: evidence from a systematic review and meta-analysis

PURPOSE

The prognostic impact of baseline C-reactive protein (CRP) in non-small-cell lung cancer (NSCLC) is debated. To evaluate this issue, we performed a systematic review and meta-analysis to explore the role of CRP value in predicting early-stage NSCLC survival.

METHODS

Ten articles on early-stage NSCLC were eligible and included in our study. We performed a random-effects meta-analysis and assessed heterogeneity and publication bias. We pooled hazard ratio (HR) estimates and their 95% confidence intervals (CIs) on mortality for the comparison between the study-specific highest category of CRP level versus the lowest one.

RESULTS

In overall analysis, elevated pretreatment CRP values were significantly associated with poor overall survival (HR 1.60, 95% CI 1.30-1.97, p&lt;0.001, I2 = 71.9%). Similar results were observed across considered strata. However, higher mortality risk was reported in studies in which CRP was combined with other factors (HR 1.96, 95% CI 1.58-2.45) and in those using a cutoff value of 3 mg/L (HR 1.89, 95% CI 1.52-2.35).

CONCLUSIONS

Based on our analysis, baseline high CRP level is significantly associated with poor prognosis in early-stage NSCLC. Further prospective controlled studies are needed to confirm these data.

Effects of NSAIDs on the risk factors of colorectal cancer: a mini review

Evidence from epidemiological and experimental studies has shown that non-steroidal anti-inflammatory drugs (NSAIDs) reduce the risk of colorectal cancer (CRC). The function of NSAIDs and the molecular targets for chemopreventive effects on CRC have been extensively studied and their data were reported. However, the relation between NSAIDs and the risk factors of CRC have not been fully elucidated yet. Thus, relations between NSAIDs and the risk factors of CRC, such as overweight and obesity, alcohol, aging, hypertriglyceridemia and smoking, are summarized with our data and with recent reported data in this review.

Aspirin and colorectal cancer: the promise of precision chemoprevention

Aspirin (acetylsalicylic acid) has become one of the most commonly used drugs, given its role as an analgesic, antipyretic and agent for cardiovascular prophylaxis. Several decades of research have provided considerable evidence demonstrating its potential for the prevention of cancer, particularly colorectal cancer. Broader clinical recommendations for aspirin-based chemoprevention strategies have recently been established; however, given the known hazards of long-term aspirin use, larger-scale adoption of an aspirin chemoprevention strategy is likely to require improved identification of individuals for whom the protective benefits outweigh the harms. Such a precision medicine approach may emerge through further clarification of aspirin's mechanism of action.