Smoking and colorectal cancer: A pooled analysis of 10 population-based cohort studies in Japan

Cigarettes and waterpipe use and risk of colorectal cancer in Iran: the IROPICAN study

We aimed to investigate the association between cigarettes and waterpipe use and colorectal cancer (CRC) in an Iranian population. We analyzed data from a multicenter hospital-based case-control study in Iran (IROPICAN). Data on tobacco smoking, including cigarettes, and waterpipe smoking, were collected in detail. Multivariate logistic regressions estimated the odds ratios (ORs) and 95% confidence intervals (CIs) for the association between cigarette and waterpipe smoking and CRC, accounting for confounders including age, sex, socioeconomic status, opium use, marital status, family history of cancer, red meat, fiber, body shape at age 15 and perceived physical workload, and each other of the two exposures. The study population consisted of 3215 controls and 848 cases, including 455 colon and 393 rectum cancers. We found no association between CRC and cigarette smoking (OR, 0.8; 95% CI, 0.6-1.0) or waterpipe smoking (OR, 1.1; 95% CI, 0.9-1.5). Analysis by categories of cigarette pack-year and frequency of waterpipe smoking (head-year) did not show associations. We observed an inverse association between colon cancer and cigarette smoking (OR, 0.6; 95% CI, 0.5-0.9). There was, however, no significant association by pack-year categories. Cigarette and waterpipe smoking was not associated with CRC in the Iranian population. Further studies are needed to better understand the role of waterpipe on CRC.

Survival and Endoscopic/Clinical Features of Patients with Colorectal Cancer Resected by Cold Snare Polypectomy: The Importance of Chronic Kidney Disease

BACKGROUND AND AIMS

Colorectal polyps resected by cold snare polypectomy (CSP) are rarely diagnosed as colorectal cancer (CRC). We aimed to investigate the prevalence, clinical features, and prognosis of patients with CRC resected by CSP.

SUBJECTS

Patients with colorectal polyps treated with CSP between 2018 and 2022 were enrolled and regularly followed up (median observation period: 30.6 months). Logistic regression analysis and decision tree analysis were employed to investigate the clinical features of the patients.

RESULTS

A total of 5,064 colorectal polyps from 2,530 patients were resected by CSP. Of these, 0.24% were diagnosed as CRC; however, no patients died due to CRC. eGFR was an independent risk factor for the presence of CRC (unit 10, OR 0.716, 95%CI 0.525-0.973, P=0.0323) and its optimal cut-off value was 59.9 mL/min/1.73 m2. The decision-tree analysis revealed that 2.03% of patients with creatinine ≥ 1.0 mg/dL had CRC.

CONCLUSION

CRC was diagnosed in 0.24% of the polyps; however, no patients died due to CRC. eGFR <60 mL/min/1.73 m2 and creatinine >1.0 mg/dL were associated with CRC. Thus, colorectal polyps should be carefully examined in patients with chronic kidney disease.

Effect of smoking on the risk of gastrointestinal cancer after cholecystectomy: A national population-based cohort study

BACKGROUND

The role of smoking in the incidence of colorectal cancer (CRC) or gastric cancer (GC) in populations undergoing cholecystectomy has not been investigated.

AIM

To evaluate the effect of smoking on CRC or GC development in cholecystectomy patients.

METHODS

A total of 174874 patients who underwent cholecystectomy between January 1, 2010 and December 31, 2017 were identified using the Korean National Health Insurance Service claims database. These patients were matched 1:1 with members of a healthy population according to age and sex. CRC or GC risk after cholecystectomy and the association between smoking and CRC or GC risk in cholecystectomy patients were evaluated using adjusted hazard ratios (HRs) and 95%CIs.

RESULTS

The risks of CRC (adjusted HR: 1.15; 95%CI: 1.06-1.25; P = 0.0013) and GC (adjusted HR: 1.11; 95%CI: 1.01-1.22; P = 0.0027) were significantly higher in cholecystectomy patients. In the population who underwent cholecystectomy, both CRC and GC risk were higher in those who had smoked compared to those who had never smoked. For both cancers, the risk tended to increase in the order of non-smokers, ex-smokers, and current smokers. In addition, a positive correlation was observed between the amount of smoking and the risks of both CRC and GC.

CONCLUSION

Careful follow-up and screening should be performed, focusing on the increased risk of gastrointestinal cancer in the cholecystectomy group, particularly considering the individual smoking habits.

A Systematic Review of the Impact of Dietary and Lifestyle Factors on Colorectal Cancer Prevention in Gulf Cooperation Council Countries

Colorectal cancer (CRC) remains a significant health burden in the Gulf Cooperation Council (GCC) countries, necessitating a deeper understanding of modifiable risk factors. Thus, the aim of the study was to evaluate the impact of dietary and lifestyle factors on the prevention of CRC in GCC countries. Studies were identified through electronic searches and reviewed based on relevant keywords. Databases searched included Ovid's MEDLINE, EMBASE, Google Scholar, and Web of Science, covering titles and abstracts published between January 1, 2000 and July 25, 2024. The search strategy encompassed four thematic areas: "colorectal cancer," "adults above 18," "risk factors," and "GCC countries." The primary focus was on dietary and lifestyle factors. Two reviewers screened titles and abstracts to determine whether the inclusion criteria were met. A total of 1,883 records were identified across these databases. After removing 513 duplicate records, 1,370 records were screened based on titles and abstracts. Of these, 1,284 records were excluded, leaving 86 full-text articles for assessment. Eight studies were ultimately included in the final systematic review, consisting of seven case-control studies and one cross-sectional study. In GCC countries, a diet rich in fruits, vegetables, and fiber has shown protective effects against CRC, while high red meat and refined carbohydrate intake may increase risk. Regular physical activity reduces CRC risk, though the impact of smoking remains inconclusive. Evidence regarding dairy products is contradictory. There is a shortage of high-quality longitudinal studies, highlighting gaps in current research and underscoring the need for larger studies with consistent methodologies.

The impact of deprivation on colorectal cancer-stage distribution in a setting with high hospital bed density: A Japanese multilevel study

BACKGROUND

A methodology for determining the appropriate balance between medical access and combating poverty remains undetermined. To address the boundary conditions for exceedingly good medical access, this study examined whether the impact of deprivation on cancer stage distribution could be eliminated in Japan, which has the highest hospital bed density in the world.

METHODS

A nationwide medical claims-based database was used to evaluate the influence of municipality-level hospital bed density and the postal code-level areal deprivation index on cancer stage at diagnosis. Given the limited number of similar studies in Japan, we focused on colorectal cancer (CRC), for which disparities have been reported in a prefecture-level study. Multilevel multivariate logistic regression models were used, with odds ratios (ORs) and 95% confidence intervals (CIs) adjusted for baseline and socioeconomic factors.

RESULTS

Regardless of the early/advanced-stage definitions, CRC consistently tended to be detected at more advanced stages in more deprived areas. In the analysis of stages 0-I/II-IV, the OR (95% CI) was 1.09 (1.05, 1.14) (p < 0.001). In the analyses of stages 0-I/II-IV and 0-II/III-IV, gradients were observed, and later detections were observed for more deprived segments. Hospital bed density was not significantly associated with the stage distribution.

CONCLUSION

The results indicate that inequalities in CRC detection due to deprivation persist even in the country with the highest hospital bed density worldwide, suggesting that poverty measures remain indispensable regardless of hospital bed access. Further investigation of various regions and cancers is required to develop a practical framework.

Colorectal cancer and its attributable risk factors in East Asia, 1990-2030

BACKGROUND

The disease burden of colorectal cancer in East Asia has been at a high level. However, the epidemiological characteristics of the disease burden in this region have not been systematically studied.

METHOD

Data were obtained from the Global Burden of Disease 2019 program. Joinpoint analysis was used to identify long-term trends in mortality of colorectal cancer. Independent effects of age, period, and cohort were detected by the age-period-cohort model. The Bayesian age-period-cohort model was performed to predict the burden of colorectal cancer across East Asia by 2030.

RESULTS

From 1990 to 2019, the average annual percentage change (AAPC) showed upward trends in mainland China (1.05 [95% confidence interval (CI)], 0.82, 1.28) as well as Taiwan Province of China (1.81 [95% CI], 1.51, 2.10) but downward in Japan (-0.60 [95% CI], -0.70, -0.49) (P < 0.05). Attributable risk factors for colorectal cancer in East Asia remained stable over 30 years, while the risk of metabolic factors is noteworthy in the future. In the next decade, the age-standardized death rate (ASDR) of colorectal cancer in China was predicted to surpass that of Japan and South Korea in expectation.

CONCLUSION

The mortality of colorectal cancer is escalating in developing countries, while it is gradually declining in high-income countries across East Asia. Nonetheless, the disease burden of colorectal cancer in high-income countries remains substantial level.

Nicotine-derived NNK promotes CRC progression through activating TMUB1/AKT pathway in METTL14/YTHDF2-mediated m6A manner

Cigarette smoking substantially promotes tumorigenesis and progression of colorectal cancer; however, the underlying molecular mechanism remains unclear. Among 662 colorectal cancer patients, our investigation revealed a significant correlation between cigarette smoking and factors, such as large tumor size, poor differentiation, and high degree of invasion. Among the nicotine-derived nitrosamines, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) emerged as the most critical carcinogen, which significantly promoted the malignant progression of colorectal cancer both in vivo and in vitro. The results of methylated RNA immunoprecipitation and transcriptome sequencing indicated that NNK upregulated transmembrane and ubiquitin-like domain-containing protein 1 (TMUB1) via N6-adenosine methylation, which was regulated by methyltransferase-like 14 (METTL14) and YTH N6-methyladenosine RNA binding protein 2 (YTHDF2). Elevated TMUB1 levels were associated with a higher risk of cancer invasion and metastasis, leading to a high mortality risk in patients with colorectal cancer. Additionally, TMUB1 promoted lysine63-linked ubiquitination of AKT by interacting with AMFR, which led to the induction of malignant proliferation and metastasis in colorectal cancer cells exposed to NNK. In summary, this study provides a new insight, indicating that targeting TMUB1 expression via METTL14/YTHDF2 mediated N6-adenosine methylation may be a potential therapeutic and prognostic target for patients with colorectal cancer who smoke.

National and subnational incidence, mortality and associated factors of colorectal cancer in China: A systematic analysis and modelling study

Background

Due to their known variation by geography and economic development, we aimed to evaluate the incidence and mortality of colorectal cancer (CRC) in China over the past decades and identify factors associated with CRC among the Chinese population to provide targeted information on disease prevention.

Methods

We conducted a systemic review and meta-analysis of epidemiolocal studies on the incidence, mortality, and associated factors of CRC among the Chinese population, extracting and synthesising data from eligible studies retrieved from seven global and Chinese databases. We pooled age-standardised incidence rates (ASIRs) and mortality rates (ASMRs) for each province, subregion, and the whole of China, and applied a joinpoint regression model and annual per cent changes (APCs) to estimate the trends of CRC incidence and mortality. We conducted random-effects meta-analyses to assess the effect estimates of identified associated risk factors.

Results

We included 493 articles; 271 provided data on CRC incidence or mortality, and 222 on associated risk factors. Overall, the ASIR of CRC in China increased from 2.75 to 19.39 (per 100 000 person-years) between 1972 and 2019 with a slowed-down growth rate (APC1 = 5.75, APC2 = 0.42), while the ASMR of CRC decreased from 12.00 to 7.95 (per 100 000 person-years) between 1974 and 2020 with a slight downward trend (APC = -0.89). We analysed 62 risk factors with synthesized data; 16 belonging to the categories of anthropometrics factors, lifestyle factors, dietary factors, personal histories and mental health conditions were graded to be associated with CRC risk among the Chinese population in the meta-analysis limited to the high-quality studies.

Conclusions

We found substantial variation of CRC burden across regions and provinces of China and identified several associated risk factors for CRC, which could help to guide the formulation of targeted disease prevention and control strategies.

Registration

PROSPERO: CRD42022346558.

Combinations of lifestyle behaviors and cancer risk among Korean adults

Combinations of lifestyle behaviors may lead to different cancer risks. This study aimed to identify the latent classes based on lifestyle behavior trajectories and to investigate the association between these latent classes and cancer risk. Participants in the 2002-2003 National Health Insurance Service general health examination were included. Data on smoking, alcohol drinking, body mass index (BMI), and physical activity measured four times between 2002 and 2009 were analyzed. Incident cancer cases were tracked from 2010 to 2018. Patterns of alcohol drinking, smoking, BMI, and physical activity and latent classes based on trajectories of smoking, alcohol drinking, BMI, and physical activity were identified. Among 2,735,110 adults (1,787,486 men and 947,624 women), 111,218 (69,089 men and 42,129 women) developed incident cancer. Six latent classes of lifestyle behavior were identified, with Class 1 (healthy class) involving only 0.2% of men and 0.5% of women. The highest risk class in males tended to be steady light drinkers and steady moderate smokers, have steady low frequency of physical activity, and be obese. This class showed a 1.47 times higher (95% CI = 1.29-1.69) risk of all cancers than did the healthy class. Among women, there was only an association between the highest risk class (tendency to be non-drinkers, light smokers) and colorectal cancer (HR = 1.70, 95% CI = 1.02-2.83). Only a small percentage of participants maintained a long-term healthy lifestyle. Identifying classes of behavior combinations and their links to cancer development is therefore critical for cancer prevention.

Smoking and risk of colorectal cancer according to KRAS and BRAF mutation status in a Japanese prospective Study

Although smoking is a major modifiable risk factor for many types of cancer, evidence for colorectal cancer is equivocal in Asian populations. Recent Western studies have proposed that the association between smoking and colorectal cancer is restricted to specific tumor molecular subtypes. However, no studies have evaluated the association according to tumor molecular subtypes in Asian populations. In a Japanese prospective population-based cohort study of 18 773 participants, we collected tumor tissues from incident colorectal cancer cases and evaluated KRAS (Kirsten rat sarcoma viral oncogene homolog) and BRAF (v-raf murine sarcoma viral oncogene homolog B) mutation status using target sequencing. Multivariable-adjusted Cox proportional hazard model was used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs) for associations of smoking with the risk of overall colorectal cancer and its subtypes defined by KRAS and BRAF mutation status. Among 339 cases, KRAS and BRAF mutations were identified in 164 (48.4%) and 16 (4.7%) cases, respectively. The multivariable-adjusted HR for ever smoking compared with never smoking was 1.24 [95% CI: 0.93-1.66], 1.75 [1.14-2.68], 0.87 [0.59-1.29], 1.24 [0.93-1.67] and 1.22 [0.38-3.93] for overall, KRAS wild-type, KRAS-mutated, BRAF wild-type and BRAF-mutated colorectal cancer, respectively. The statistically significant heterogeneity was indicated between KRAS mutation status (Pheterogeneity = 0.01) but not between BRAF mutation status. This study is the first to demonstrate that smokers have an approximately 2-fold higher risk of KRAS wild-type colorectal cancer than never smokers in an Asian population. Our findings support that smoking is a risk factor for colorectal cancer, especially for its subtype without KRAS mutations, in Asian populations.

An adjusted Asia-Pacific colorectal screening score system to predict advanced colorectal neoplasia in asymptomatic Chinese patients

PURPOSE

The Asia-Pacific Colorectal Screening (APCS) score and its derivatives have been used to predict advanced colorectal neoplasia (ACN). However, it remains unknown whether they apply to the current Chinese population in general clinical practice. Therefore, we aimed to update the APCS score system by applying data from two independent asymptomatic populations to predict the risk of ACN in China.

METHODS

We developed an adjusted APCS (A-APCS) score by using the data of asymptomatic Chinese patients undergoing colonoscopies from January 2014 to December 2018. Furthermore, we validated this system in another cohort of 812 patients who underwent screening colonoscopy between January and December 2021. The discriminative calibration ability of the A-APCS and APCS scores was comparatively evaluated.

RESULTS

Univariate and multivariate logistic regression were applied to assess the risk factors for ACN, and an adjusted scoring system of 0 to 6.5 points was schemed according to the results. Utilizing the developed score, 20.2%, 41.2%, and 38.6% of patients in the validation cohort were classified as average, moderate, and high risk, respectively. The corresponding ACN incidence rates were 1.2%, 6.0%, and 11.1%, respectively. In addition, the A-APCS score (c-statistics: 0.68 for the derivation and 0.80 for the validation cohort) showed better discriminative power than using predictors of APCS alone.

CONCLUSIONS

The A-APCS score may be simple and useful in clinical applications for predicting ACN risk in China.

Association between metabolic syndrome and participation in colorectal cancer screening in Japan: A retrospective cohort analysis using LIFE study data

BACKGROUND

People with metabolic syndrome have an elevated risk of developing colorectal cancer (CRC), and are recommended to undergo cancer screening. This study examined the association between metabolic syndrome and CRC screening participation in Japan.

METHODS

This retrospective cohort study was conducted using insurance claims data, health checkup data, and cancer screening data from a Japanese city. The study population comprised persons aged 40-74 years who had undergone health checkups between fiscal years (FY) 2016 and 2019. The exposure was metabolic syndrome risk (high risk, moderate risk, and no risk) as determined during health checkups. The outcome was CRC screening participation. Logistic regression analyses were performed to examine the associations between metabolic syndrome risk and CRC screening participation.

RESULTS

We analyzed 20,558 people in the FY2016 cohort, 19,065 people in the FY2017 cohort, 17,496 people in the FY2018 cohort, and 15,647 people in the FY2019 cohort. The odds of CRC screening participation were significantly lower in the moderate-risk group (P < 0.05) in all FYs except FY2019 and the high-risk group (P < 0.001) in all FYs when compared with the no-risk group. When analyzed according to age group, older persons aged 65-74 years generally had significantly lower odds of CRC screening participation than persons aged 40-49 years across all metabolic syndrome risk groups.

CONCLUSION

This is the first study from Japan to show that people with metabolic syndrome, especially older persons aged 65-74 years, are less likely to undergo CRC screening than people without metabolic syndrome. These findings indicate a need to develop and implement age-specific measures to increase cancer screening uptake among persons with metabolic syndrome.

Risk factors for early-onset colorectal cancer: A large-scale Chinese cohort study

Background

The incidence of early-onset colorectal cancer (EOCRC) has increased globally since the early 1990s. Comprehensively examining the risk factors would be helpful for risk stratification and the development of personalized colorectal cancer screening strategies.

Methods

We performed a prospective study of the Chinese population aged 30-50 years to identify potential risk factors during a median follow-up of 9.1 years. We compared the distribution of demographic characteristics, lifestyle factors, dietary habits, and medical history among 222 EOCRC cases and 87,833 normal controls. Multivariate adjusted Cox hazard models were used for estimating EOCRC risks of each risk factor.

Results

Our final analyses indicated that participants with a higher body mass index (HR, 1.04; 95% CI:1.00,1.08), regular alcohol consumption (HR, 1.69; 95% CI: 1.12, 2.91), higher intake of fish (HR, 1.64; 95% CI: 1.01, 2.67), hypertension (HR, 1.99; 95% CI: 1.04, 3.81), diabetes (HR, 2.20; 95% CI: 1.08, 4.49), and first-degree relatives with cancer (HR, 1.70; 95% CI: 1.23, 2.36) were at higher risk of EOCRC.

Conclusion

We identified several modifiable as well as nonmodifiable risk factors, such as higher BMI, alcohol and fish consumption, hypertension, and diabetes, were associated with EOCRC.

Acetylsalicylic Acid Effect in Colorectal Cancer Taking into Account the Role of Tobacco, Alcohol and Excess Weight

Excess weight, smoking and risky drinking are preventable risk factors for colorectal cancer (CRC). However, several studies have reported a protective association between aspirin and the risk of CRC. This article looks deeper into the relationships between risk factors and aspirin use with the risk of developing CRC. We performed a retrospective cohort study of CRC risk factors and aspirin use in persons aged >50 years in Lleida province. The participants were inhabitants with some medication prescribed between 2007 and 2016 that were linked to the Population-Based Cancer Registry to detect CRC diagnosed between 2012 and 2016. Risk factors and aspirin use were studied using the adjusted HR (aHR) with 95% confidence intervals (CI) using a Cox proportional hazard model. We included 154,715 inhabitants of Lleida (Spain) aged >50 years. Of patients with CRC, 62% were male (HR = 1.8; 95% CI: 1.6-2.2), 39.5% were overweight (HR = 2.8; 95% CI: 2.3-3.4) and 47.3% were obese (HR = 3.0; 95% CI: 2.6-3.6). Cox regression showed an association between aspirin and CRC (aHR = 0.7; 95% CI: 0.6-0.8), confirming a protective effect against CRC and an association between the risk of CRC and excess weight (aHR = 1.4; 95% CI: 1.2-1.7), smoking (aHR = 1.4; 95% CI: 1.3-1.7) and risky drinking (aHR = 1.6; 95% CI: 1.2-2.0). Our results show that aspirin use decreased the risk of CRC and corroborate the relationship between overweight, smoking and risky drinking and the risk of CRC.

Pandemic-resilient target setting in colorectal cancer screening for vulnerable older population

BACKGROUND

Colorectal cancer screening (CRCS) needs to be pandemic-resilient to avoid long-lasting shutdowns; however, realistic participation target remains unelucidated. This study aimed to identify the lowest acceptable participation rate in CRCS during a pandemic, focusing on vulnerable older populations who require urgent intervention.

METHODS

This nationwide cross-sectional study included 80,946 inpatients aged 70-85 years who were first diagnosed with colorectal cancer (CRC) after 70 years of age, between April 1, 2014 and March 31, 2019, in Japan. To evaluate the association between area-level CRCS participation rate and individual early CRC detection, a multilevel logistic regression model was constructed. The mandatorily implemented screening rates were converted to the total screening rate equivalents (TSREs), which reflect the remaining contributions of voluntarily provided screenings.

RESULTS

Early detections during stages 0-I were significantly observed when primary screening rate was ≥38% (TSRE) and combined follow-up rate was ≥85%. For early detection during Tis-T1, primary screening rate ≥ 38% (TSRE) and combined follow-up rate ≥ 90% were necessary. For follow-up rates ≥70% or ≥75%, there were cases where missed detection of Tis-T1 were observed.

CONCLUSION

The results indicate that, even during pandemic, CRCS should achieve a primary screening rate of 38% and follow-up rate of 85% for vulnerable older populations. These values, lower than the current desirable rates, suggest the maximum possible compromise in balancing the resources between cancer screening and pandemic measures. Moreover, they also indicate the minimum target for shifting to fecal immunochemical test-focused program. Further explorations with varied CRCS settings are necessary for verification.

Attitudes and practices of tobacco cessation counseling among Saudi dental professionals: A nationwide cross-sectional survey

Background

Dental professionals can play a pivotal role in educating the public about the harmful effects of smoking and encouraging them to quit the habit.

Aim

This study assesses the attitudes and practices of tobacco cessation counseling (TCC) among dental professionals in Saudi Arabia.

Patients and Methods

This questionnaire-based cross-sectional study targeted dentists and dental interns working in government and private sectors in Saudi Arabia. We conducted a descriptive analysis by using SPSS Statistics, version 25.0.

Results

A total of 895 respondents (314 interns and 581 dentists) participated in this survey. Although the majority of respondents (93%) reported that they always ask patients about tobacco habits, only 59% reported recording tobacco habits in patients' files, and only 55% of the respondents reported explaining to patients the harmful effects of tobacco. Around 91% of the participants believe that a dental clinic is an appropriate place for TCC, and 22% believe that TCC has a negative impact on dental practice. Smoking status, work setting, and the number of years since graduation were found to be significantly associated with the respondents' attitudes and practices. Lack of training, time limitations, and lack of confidence were barriers for TCC.

Conclusions

Dental professionals in Saudi Arabia demonstrated relatively positive attitudes but weak practices of TCC. Continuous education and motivation are needed to improve dentists' confidence, attitudes, and willingness for TCC. Integration of tobacco control education in undergraduate curricula is recommended.

Burden of cancer attributable to tobacco smoke in Japan in 2015

Tobacco is the greatest single cause of many non-communicable diseases, including cancer. We calculated the proportion of cancer incidence and mortality in 2015 attributable to tobacco smoking and exposure to secondhand smoke (SHS). Data on the prevalence of active smoking were derived from the 2005 Japanese National Health and Nutrition Survey by age group and gender. For SHS exposure prevalence, data from a nationwide cross-sectional survey from 2004-2005 were used. Based on standard formulas, population attributable fractions (PAFs) for each cancer causally associated with active smoking, namely the oral cavity and pharynx, esophagus, stomach, colon, rectum, liver, pancreas, nasal, larynx, lung, uterine cervix, kidney, renal pelvis and ureter, bladder, and acute myeloid leukemia, were calculated for each sex and age group and aggregated to obtain the PAF among total cancer incidence and mortality. For SHS exposure, PAFs for lung cancer and total cancer were calculated using the same method. For Japan in 2015, 145,765 new cancer cases and 72,520 cancer deaths, corresponding to a PAF of 15.2% for total cancer incidence and 19.6% for total cancer mortality, were attributable to active tobacco smoking. For SHS exposure, 0.5% of total cancer incidence and 0.7% of total cancer mortality in 2015 were attributable. Tobacco is still one of the major causes of cancer in Japan.

Association between metabolic syndrome and its components and incident colorectal cancer in a prospective cohort study

BACKGROUND

Metabolic syndrome (MetS) has been identified as a contributor to cancer development. However, reports concerning the association between MetS and colorectal cancer (CRC) have been inconsistent. This study investigated whether MetS, its components, and the number of components increase the risk of CRC.

METHODS

This was a prospective cohort study of 41,837 participants recruited from August 2002 to December 2014 from the National Cancer Center in South Korea. The participants were followed until December 2017 to identify incident CRC cases. The participants underwent laboratory tests at the baseline. Additionally, a self-administered questionnaire collected information concerning lifestyle and general characteristics at the baseline. A Cox proportional hazards model was used to calculate the hazard ratios (HRs) and 95% confidence intervals (CIs) to explore the association between MetS and its components and CRC risk after adjustments for confounding variables.

RESULTS

In total, 128 incident CRC cases were identified during the follow-up period. An increased CRC risk was found among participants with MetS (HR, 1.63; 95% CI, 1.08-2.44). Additionally, elevated blood pressure (HR, 1.50; 95% CI, 1.05-2.15) and a high fasting glucose level (HR, 1.80; 95% CI, 1.23-2.63) were associated with an elevated risk of CRC. Notably, an increased risk was identified among participants with abdominal obesity coexisting with another component of MetS.

CONCLUSIONS

These results suggest that MetS is a risk factor for CRC. Greater emphasis should be placed on the importance of CRC screening among individuals with abdominal obesity coexisting with another component of MetS.

LAY SUMMARY

Colorectal cancer (CRC) ranks as the third most common cancer type in terms of incidence. Metabolic syndrome (MetS) has been identified as a contributor to cancer development. However, the association between MetS and CRC remains controversial because of a lack of consistent findings in previous studies. In this study, the National Cholesterol Education Program's Adult Treatment Panel III guidelines are used for the diagnosis of MetS. MetS is found to be a predictor of CRC. Additionally, the importance of CRC screening among individuals with 2 components of MetS should be emphasized.

Combining repurposed drugs to treat colorectal cancer

The drug development process, especially of antineoplastic agents, has become increasingly costly and ineffective. Drug repurposing and drug combination are alternatives to de novo drug development, being low cost, rapid, and easy to apply. These strategies allow higher efficacy, decreased toxicity, and overcoming of drug resistance. The combination of antineoplastic agents is already being applied in cancer therapy, but the combination of repurposed drugs is still under-explored in pre- and clinical development. In this review, we provide a set of pharmacological concepts focusing on drug repurposing for treating colorectal cancer (CRC) and that are relevant for the application of new drug combinations against this disease.

Combining the Fecal Immunochemical Test with a Logistic Regression Model for Screening Colorectal Neoplasia

Background: The fecal immunochemical test (FIT) is a widely used strategy for colorectal cancer (CRC) screening with moderate sensitivity. To further increase the sensitivity of FIT in identifying colorectal neoplasia, in this study, we established a classifier model by combining FIT result and other demographic and clinical features.

Methods: A total of 4,477 participants were examined with FIT and those who tested positive (over 100 ng/ml) were followed up by a colonoscopy examination. Demographic and clinical information of participants including four domains (basic information, clinical history, diet habits and life styles) that consist of 15 features were retrieved from questionnaire surveys. A mean decrease accuracy (MDA) score was used to select features that are mostly related to CRC. Five different algorithms including logistic regression (LR), classification and regression tree (CART), support vector machine (SVM), artificial neural network (ANN) and random forest (RF) were used to generate a classifier model, through a 10X cross validation process. Area under curve (AUC) and normalized mean squared error (NMSE) were used in the evaluation of the performance of the model.

Results: The top six features that are mostly related to CRC include age, gender, history of intestinal adenoma or polyposis, smoking history, gastrointestinal discomfort symptom and fruit eating habit were selected. LR algorithm was used in the generation of the model. An AUC score of 0.92 and an NMSE score of 0.076 were obtained by the final classifier model in separating normal individuals from participants with colorectal neoplasia.

Conclusion: Our results provide a new “Funnel” strategy in colorectal neoplasia screening via adding a classifier model filtering step between FIT and colonoscopy examination. This strategy minimizes the need of colonoscopy examination while increases the sensitivity of FIT-based CRC screening.

Association between tobacco substance usage and a missense mutation in the tumor suppressor gene P53 in the Saudi Arabian population

The tumor suppressor gene TP53 and its downstream genes P21 and MDM2 play crucial roles in combating DNA damage at the G1/S cell cycle checkpoint. Polymorphisms in these genes can lead to the development of various diseases. This study was conducted to examine a potential association between tobacco substance usage (TSU) and single-nucleotide polymorphism (SNP) at the exon regions of the P53, P21, and MDM2 genes by comparing populations of smokers and non-smokers from Saudi Arabia. P53 rs1042522 (C/G), P21 rs1801270 (A/C), and MDM2 rs769412 (A/G) were investigated by genotyping 568 blood specimens: 283 from male/female smokers and 285 from male/female non-smokers. The results obtained from the smokers and their control non-smokers were compared according to age, sex, duration of smoking, and type of TSU. Heterozygous CG, homozygous GG, and CG+GG genotypes, as well as the G allele of rs1042522 were significantly associated with TSU in Saudi smokers compared with non-smokers. The C allele frequency of rs1801270 was also associated with TSU in smokers (OR = 1.33, p = 0.049) in comparison with non-smokers, in younger smokers (≤29 years) (OR = 1.556, p = 0.03280) in comparison with non-smokers of the same age, in smokers who had smoked cigarettes for seven years or less (OR = 1.596, p = 0.00882), and in smokers who had consumed shisha (OR = 1.608, p = 0.04104) in comparison with the controls. However, the genotypic and allelic frequencies for rs769412 did not show significant associations with TSU in Saudis. The selected SNP of P53 was strongly associated with TSU and may be linked to TSU-induced diseases in the Saudi Arabian population.