Body weight gain and risk of colorectal cancer: a systematic review and meta-analysis of observational studies

Weight Gain in Midlife Women

PURPOSE OF REVIEW

To summarize the evidence and clinical implications of weight and body composition changes during midlife in women and provide an overview of weight gain prevention and management in this population.

RECENT FINDINGS

Aging-related changes such as decreased energy expenditure and physical activity are important culprits for weight gain in midlife women. The hormonal changes of menopause also influence body adiposity distribution and increase central adiposity. These body changes can have health consequences including the development of cardiometabolic diseases, osteoarthritis, cancer, worsening in cognition, mental health, and menopause symptoms. Midlife women experience changes related to aging, menopause, and lifestyle which favor weight gain. Clinical practice should focus on early counseling and anticipatory guidance on the importance of dietary changes and physical activity to attenuate this phenomenon. Future research should focus on the longitudinal relationship between weight trends in midlife and health consequences and mortality.

Cost-effectiveness of semaglutide 2.4 mg in chronic weight management in Portugal

BACKGROUND

Obesity and overweight are a significant public health concern. Subcutaneous semaglutide 2.4 mg injection is a glucagon-like peptide-1 (GLP-1) analogue approved by the European Medicines Agency as an adjunct to a reduced calorie diet and increased physical activity (diet and exercise, D&E) for the treatment obesity and overweight in the presence of at least one weight related comorbidity. This study aimed to assess the cost-effectiveness of semaglutide 2.4 mg in combination with D&E compared to D&E alone for the Portuguese setting.

METHODS

Analysis were conducted using the Core Obesity Model (COM) version 18, a Markov state transition cohort model, to predict the health outcomes and costs of weight related complications based on changes in surrogate endpoints. Efficacy and safety data were sourced from the STEP trials (Body Mass Index, systolic blood pressure and glycemic status) from a cohort of adults aged on average 48 years with obesity (BMI ≥ 30 kg/m2) and ≥ 1 obesity-related comorbidities, over a time horizon of 40 years. Costs were estimated from the perspective of the Portuguese National Health Service. Sensitivity analyses were conducted to test the robustness of results across a range of assumptions.

RESULTS

On a patient level, Semaglutide 2.4 mg in addition to D&E compared to D&E alone, improved QALYs by 0.098 and yielded higher costs by 1,325 EUR over a 40-year time horizon, with an ICER of 13,459 EUR per QALY gained and 100% probability of cost-effectiveness at the given WTP. Semaglutide 2.4 mg remained cost-effective across all different scenarios and sensitivity analysis at a WTP of 20,000 EUR per QALY. Among the subpopulations examined, Semaglutide 2.4 mg yielded ICERs of 18,459 EUR for patients with BMI ≥ 30 kg/m2 and of 22,657 EUR for patients with BMI ≥ 35 kg/m2.

CONCLUSIONS

Semaglutide 2.4 mg was cost-effective compared to D&E alone for patients with obesity (BMI ≥ 30 kg/m2) and weight related comorbidities in Portugal, over a 40-year time horizon.

Trends in the burden of most common obesity-related cancers in 16 Southern Africa development community countries, 1990-2019. Findings from the global burden of disease study

Background

Obesity-related cancers in the 16 Southern African Development Community (SADC) countries is quite prominent. The changes and time trends of the burden of obesity-related cancers in developing countries like SADC remain largely unknown. A descriptive epidemiological analysis was conducted to assess the burden of obesity-related cancers, (liver, esophageal, breast, prostate, colon/rectal, leukemia, ovarian, uterine, pancreatic, kidney, gallbladder/biliary tract, and thyroid cancers) in SADC countries.

Methods

Data from the 2019 Global Burden of Diseases Study was used. Deaths extracted from vital registration, verbal autopsies and ICD codes. Cancer-type, mortality and prevalence per 100,000 population and 95% uncertainty intervals (UIs) were calculated using the Cause of Death Ensemble model and Spatio-Temporal Gaussian process with mixed effects regression models. Annual rates of change (AROCs) between 1990 and 2019 and the corresponding UIs were calculated.

Results

The top age-standardized mortality rates per 100,000 in 2019 for males were leukemia, 20.1(14.4-26.4), esophageal cancer, 15.1 (11.2-19.1), and colon and rectal cancer, 10.3 (8.6-12.6). For females, breast cancer, 20.6 (16.6-25.0), leukemia, 17.1 (11.4-23.7), and esophageal cancer, 8.3 (5.5-10.7), had the leading mortality rates. For males, AROC substantial (p < 0.05) increase for kidney cancer for 11 of the countries (AROC from 0.41% to 1.24%), colon cancer for eight of the countries (from 0.39% to 0.92%), and pancreatic cancer for seven countries (from 0.26% to 1.01%). In females, AROC showed substantial increase for pancreatic cancer for 13 of the countries from (0.34%-1.67%), nine countries for kidney cancer (from 0.27% to 1.02%), seven countries each for breast cancer (0.35%-1.13%), and ovarian cancer (from 0.33% to 1.21%).

Conclusions

There is need for location-specific and culturally appropriate strategies for better nutrition and weight control, and improved screening for all cancers. Health promotion messaging should target kidney, colon, pancreatic, and breast cancers and encourage clinically tested methods of reducing BMI such as increasing personal physical activity and adoption of effective dietary regimes.

Factors influencing advanced colorectal neoplasm anatomic site distribution in China: An epidemiological study based on colorectal cancer screening data

OBJECTIVE

Existing studies indicate that advanced colorectal neoplasms exhibit distinct clinical and biological traits based on anatomical sites. However, in China, especially for advanced colorectal neoplasms, there's limited information available on these traits. Our primary objective is to comprehensively study the characteristics of advanced colorectal neoplasm patients in different anatomical sites in China.

METHODS

We selected information from the colorectal cancer screening database in Tianjin, China, since 2010 as the study subject. We chose valid information from 3113 patients with comprehensive data and diagnosed advanced colorectal neoplasms (ANs) from a pool of 19,308 individuals to be included in the study. We then conducted further analysis to examine the correlation between these epidemiological data and tumor location.

RESULTS

Among the 3113 patients, neoplasms in the left side of the colon accounted for the largest proportion, while neoplasms in the right side of the colon had the smallest proportion, followed by rectal neoplasms. The highest proportion of advanced colorectal neoplasms was found among men. In the age group of 39-49 years old, the proportion of left late-stage advanced colon neoplasms was equal to that of right late-stage advanced colon neoplasms, while late-stage advanced rectal neoplasms increased with age. Smoking, drinking, and a history of colon cancer in first-degree relatives showed statistically significant associations with the location distribution of advanced colorectal neoplasms. A history of appendicitis, appendectomy, cholecystitis, or cholecystectomy did not significantly affect the location distribution of advanced colorectal neoplasms. However, among patients with such histories, there was a statistically significant relationship between advanced colon neoplasms on the right and those on the left and in the rectum. Similar results were observed for BMI.

CONCLUSION

Our research findings demonstrate that advanced colorectal neoplasms display unique epidemiological characteristics depending on their anatomical locations, and these distinctions deviate from those observed in Western populations. These insights contribute to a more comprehensive understanding of the topic and offer valuable guidance for future research in China. We advocate for further investigations centered on the anatomical location of colorectal neoplasms to enhance the precision of colorectal cancer (CRC) screening and treatment.

Cancer mortality and competing causes of death in older adults with cancer: A prospective, multicentre cohort study (ELCAPA-19)

BACKGROUND

In older patients with cancer, comorbidities compete with cancer for cause of death. The objectives were to evaluate cancer mortality and factors associated, according to metastatic status.

METHODS

Between 2007 and 2014, patients with cancer aged ≥70 referred for pre-therapeutic geriatric assessment (GA) were included through the ELCAPA prospective cohort study. The underlying cause of death was defined according to the International Classification of Diseases, 10th Revision. The World Health Organisation definition was used to categorise the cause of death as cancer versus another disease (e.g. cardiovascular disease, infectious disease, etc.) Competing risk models were used.

RESULTS

Mean (SD) age of the 1445 included patients was 80.2 (5.8) and 48% were women. Most common tumour sites were colorectal (19%), breast (17%) and urinary (15%); 773 patients (49%) had metastases. After a 34-month median follow-up, 706 cancer deaths were observed among 843 deaths. The 6-month and 3-year cancer mortality rates (95% CI) were 12% (9-15) and 34% (29-38) for non-metastatic patients and 43% (39-47) and 79% (75-82) for metastatic patients, respectively. Dependency in activities of daily living and comorbidities were associated with 6-month and 3-year cancer mortality in non-metastatic (adjusted subhazard ratio [aSHR] = 1.68 [0.99-2.85] and 1.69 [1.16-2.45]; and 1.98 [1.08-3.63] and 3.38 [1.47-7.76], respectively) and metastatic patients (aSHR = 2.81 [2.01-3.93] and 2.95 [2.14-4.07]; and 1.63 [1.18-2.25] and 2.06 [1.39-3.05], respectively). Impaired Timed-Get-Up-and-Go test was associated with 6-month and 3-year cancer mortality in metastatic patients (aSHR = 1.5 [1.06-2.12] and 1.38 [1.06-1.81], respectively). Obesity was negatively associated with 3-year cancer death in non-metastatic (aSHR = 0.53 [0.29-0.97]) and metastatic patients (aSHR = 0.71 [0.51-1.00]).

CONCLUSIONS

The majority of older adults with cancer referred for pre-therapeutic GA die from cancer. Geriatric parameters are independently associated with cancer mortality and should be considered for prognosis assessment, decision-making and care.

Leptin: A Heavyweight Player in Obesity-Related Cancers

Obesity, defined as the abnormal or excessive expansion of white adipose tissue, has reached pandemic proportions and is recognized as an important health concern since it is a common root for several comorbidities, including malignancies. Indeed, the current knowledge of the white adipose tissue, which shifts its role from an energy storage tissue to an important endocrine and metabolic organ, has opened up new avenues for the discovery of obesity's effects on tumor biology. In this review, we will report the epidemiological studies concerning the strong impact of obesity in several types of cancer and describe the mechanisms underlying the heterotypic signals between cancer cell lines and adipocytes, with particular emphasis on inflammation, the insulin/IGF-1 axis, and adipokines. Among the adipokines, we will further describe the in vitro, in vivo, and clinical data concerning the role of leptin, recognized as one of the most important mediators of obesity-associated cancers. In fact, leptin physiologically regulates energy metabolism, appetite, and reproduction, and several studies have also described the role of leptin in affecting cancer development and progression. Finally, we will summarize the newest pharmacological strategies aimed at mitigating the protumorigenic effects of leptin, underlining their mechanisms of action.

Risk of Colorectal Cancer Associated With Lifetime Excess Weight

Importance

Excess weight is associated with increased cancer risk, but the risk may have been underestimated, as previous studies did not consider cumulative lifetime exposure.

Objective

To assess the association of cumulative lifetime excess weight with risk of colorectal cancer (CRC).

Design, Setting, and Participants

In a population-based case-control study conducted since 2003 in Germany, height and self-reported weight documented in 10-year increments starting at age 20 years up to the current age were obtained from 5635 individuals with CRC and 4515 persons serving as controls. Body mass index (BMI), calculated as weight in kilograms divided by height in meters squared, was calculated for each year of age from age 20 years to the current age by linear interpolation. Excess BMI (eBMI) at each year of age was determined as BMI - 25 and summed across ages to obtain the weighted number of years lived with overweight or obesity (WYOs), determined as year × eBMI. The eBMI was set to 0 in case of a BMI below 25. Associations with CRC risk were estimated for BMI at various ages and for WYOs by multiple logistic regression. Data analyses were performed from June 4, 2021, to December 17, 2021.

Main Outcomes and Measures

Relative risk of CRC according to lifetime exposure to excess weight compared with relative risks according to BMI at various ages.

Results

The mean (SD) age of the patients with CRC (n = 5635) was 68.4 (10.9) years; 3366 were men (59.7%); mean (SD) age of the control participants (n = 4515) was 68.5 (10.6) years; 2759 were men (61.1%). An association was observed between WYOs and CRC risk, with adjusted odds ratios (ORs) increasing from 1.25 (95% CI, 1.09-1.44) to 2.54 (95% CI, 2.24-2.89) from the first to the fourth quartile of WYOs compared with participants who remained within the normal weight range. Each SD increment in WYOs was associated with an increase of CRC risk by 55% (adjusted OR, 1.55; 95% CI, 1.46-1.64). This OR was higher than the OR per SD increase of eBMI at any single point of time, which ranged from 1.04 (95% CI, 0.93-1.16) to 1.27 (95% CI 1.16-1.39).

Conclusions and Relevance

The results of this case-control study suggest a greater role of cumulative lifetime excess weight for CRC risk than estimated by traditional analyses based on BMI measures taken at a single point.

Global, regional, and national burden of cancers attributable to excess body weight in 204 countries and territories, 1990 to 2019

OBJECTIVE

The aim of this study was to report the level and trends of 13 cancers that are attributable to excess body weight (EBW) for 204 countries and territories from 1990 to 2019.

METHODS

Using publicly available data, the burden of cancers attributable to EBW was reported from 1990 to 2019 based on the comparative risk assessment approach used in the Global Burden of Disease study 2019. [Correction added on 27 January 2022, after first online publication: 'Using publicly available data,' has been added before the first sentence and 'estimated' was corrected to 'reported'.] RESULTS: In 2019, EBW caused 11.2 million disability-adjusted life-years (DALYs), or 4.4% of all cancer-related DALYs. Between 1990 and 2019, the global EBW-attributable age-standardized cancer DALY rates (per 100,000) increased from 109.9 to 133.9, a relative increase of 21.9%. The age-standardized DALY rates (per 100,000) of cancers attributable to EBW in 2019 were highest and lowest in Mongolia (611.8) and Bangladesh (30.2), respectively. The 60- to 64-year age group had the highest number of DALYs attributable to EBW, whereas there were no large sex differences in the cancer-related burden attributable to EBW. Furthermore, the association between the age-standardized DALY rates and the sociodemographic index was generally positive.

CONCLUSIONS

Overall, the EBW-attributable burden of cancers has increased in the past three decades. Public health efforts should focus on identifying appropriate preventive interventions at the population and individual levels, especially in the regions and countries with the highest burden.

Dietary Risk Factors and Odds of Colorectal Adenoma in Malaysia: A Case Control Study

Current evidence suggests that dietary and lifestyle factors may play an important role in colorectal cancer risk but there are only a few studies that investigated their relationship with colorectal adenomas (CRA), the precursors for colorectal cancer. A case-control study was conducted to determine the relationship between dietary and lifestyle factors associated with CRA risk among 125 subjects with CRA and 150 subjects without CRA at Hospital Canselor Tuanku Muhriz UKM (HCTM), Malaysia. We used dietary history questionnaire (DHQ) and International Physical Activity Questionnaire-Short Form (IPAQ) to estimate the diet and physical activity. The findings of this study showed that male gender [OR = 2.71 (95% CI= 1.01-7.27)], smoking [OR = 6.39 (95% CI= 1.04-39.30)], family history of cancer [OR = 6.39 (95% CI= 1.04-39.30)], high body fat percentage [OR = 1.25 (95% CI= 1.04-1.51)], high calorie and fat intake [OR = 1.03 (95% CI= 1.01-1.06)], [OR = 1.01 (95% CI= 0.95-1.09)] and red meat intake more than 100 g per day [OR = 1.02 (95% CI= 1.01-1.04)] increased CRA risk. High fiber [OR = 0.78 (95% CI= 0.64-0.95)] and calcium intake [OR = 0.78 (95% CI= 0.98-1.00)] was found to decrease CRA risk. Some of these modifiable risk factors could be advocated as lifestyle interventions to reduce risk of CRA.

Increased risk of second primary malignancies among endometrial cancer survivors receiving surgery alone: A population-based analysis

Background

Women with endometrial cancer (EC) have favorable prognoses, leaving them vulnerable to the development of second primary cancers (SPCs). We investigated the SPC risk and survival outcomes among EC patients treated with surgery alone in order to exclude the impact of adjuvant treatment on the results.

Methods

Data from the Taiwan Cancer Registry from 1995 to 2013 were analyzed. Standardized incidence ratios (SIRs) of SPCs among EC survivors were calculated.

Results

Among 7725 women enrolled, 478 developed an SPC. The overall SIR for SPCs in EC survivors was 2.84 (95% confidence interval [CI] 2.59–3.10) compared with the general female population. Women diagnosed with EC at age <50 years had a higher SIR for an SPC than those diagnosed at age ≥50 years (SIR = 4.38 vs. 1.28). The most frequent site of an SPC was the small intestine (SIR = 8.39, 95% CI 2.72–19.58), followed by the kidney (SIR = 4.84, 95% CI 1.78–10.54), and oral cavity (SIR = 4.52, 95% CI 2.17–8.31). Women, regardless of age at EC diagnosis, had significantly higher SIRs for subsequent breast, colorectal, lung, and thyroid cancer, and lymphoma. Women with an SPC had shorter overall survival than those without (5‐year: 88.9 vs. 94.2%, 10‐year: 71.3 vs. 89.8%, 15‐year: 62.3 vs. 86.1%, and 20‐year: 47.6 vs. 81.1%, all ps<0.001).

Conclusions

Even women treated for EC with surgery alone, especially young EC survivors, had an increased risk of SPCs. Genetic counseling/testing is recommended for young EC patients, and all are recommended to receive regular surveillance and screening for breast, colorectal, and lung cancers.

Lifestyle changes and risk of cancer: experience from the Swedish women's lifestyle and health cohort study

BACKGROUND

The impact of lifestyle changes on cancer risk is yet to be elucidated. We investigated this issue in the Swedish Women's Lifestyle and Health Cohort Study.

MATERIAL AND METHODS

We measured changes by comparing two questionnaires, filled in 1991/92 and 2003. We followed women for cancer from 2003 until 2012. We used Cox regression models to assess the effect of changes in smoking, alcohol consumption, body mass index (BMI), physical activity and a lifestyle score on the risk of lifestyle-related cancer. One point was added to the lifestyle score for each of these: non-smoking, alcohol consumption ≤12 grams/day, BMI <25 kg/m2 and high level of physical activity.

RESULTS

We included 29,930 women. From 1991/92 to 2003, median age changed from 40.0 to 51.7 years, alcohol consumption from 2.5 to 4.7 grams/day, BMI from 22.7 to 24.5 kg/m2, proportion of current smokers from 31.0 to 20.6% and women reporting high physical activity from 27.2 to 37.0%. Women who quit smoking had lower risk of smoking-related cancers compared to women who continued (hazard ratio (HR) 0.74, 95% confidence interval (CI) 0.55-1.00). Women who reduced their weight by more than 5%, compared to women with stable weight, had lower risk of breast cancer (HR 0.49, 95% CI 0.31-0.78). Among women with score of 0-2 in 1992/93, those who improved to 3-4 had lower risk of lifestyle-related cancers compared to women who did not (HR 0.81, 95% CI 0.66-0.99).

CONCLUSIONS

Healthy lifestyle changes, particularly smoking cessation and weight reduction, were associated with a decreased risk of cancer.

Comprehensive Assessment of Diet Quality and Risk of Precursors of Early-Onset Colorectal Cancer

BACKGROUND

The role of poor diet quality in the rising incidence of colorectal cancer (CRC) diagnosed younger than age 50 years has not been explored. Based on molecular features of early-onset CRC, early-onset adenomas are emerging surrogate endpoints.

METHODS

In a prospective cohort study (Nurses' Health Study II), we evaluated 2 empirical dietary patterns (Western and prudent) and 3 recommendation-based indexes (Dietary Approaches to Stop Hypertension [DASH], Alternative Mediterranean Diet [AMED], and Alternative Healthy Eating Index [AHEI]-2010) with risk of early-onset adenoma overall and by malignant potential (high-risk: ≥1 cm, tubulovillous or villous histology, high-grade dysplasia, or ≥3 adenomas), among 29 474 women with 1 or more lower endoscopy before age 50 years (1991-2011). Multivariable logistic regressions were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs).

RESULTS

We documented 1157 early-onset adenomas with 375 at high risk. Western diet was positively associated, whereas prudent diet, DASH, AMED, and AHEI-2010 were inversely associated with risk of early-onset adenoma. The associations were largely confined to high-risk adenomas (the highest vs lowest quintile: Western, OR = 1.67, 95% CI = 1.18 to 2.37; prudent, OR = 0.69, 95% CI = 0.48 to 0.98; DASH, OR = 0.65, 95% CI = 0.45 to 0.93; AMED, OR = 0.55, 95% CI = 0.38 to 0.79; AHEI-2010, OR = 0.71, 95% CI = 0.51 to 1.01; all Ptrend ≤ .03), driven by those identified in the distal colon and rectum (all Ptrend ≤ .04, except AMED: Ptrend = .14).

CONCLUSION

Poor diet quality was associated with an increased risk of early-onset distal and rectal adenomas of high malignant potential. These findings provide preliminary but strong support to the role of diet in early-onset CRC.

The Prognostic Role of Body Mass Index in Survival of Non-metastatic Postoperative Patients with Colorectal Cancer

Background: Rather body mass index (BMI) has a potential prognostic role in determining the outcome of patients suffering from colorectal cancer or not should be clear. Objectives: We aimed at determining the potential effects of BMI on the prognosis of patients with colorectal cancer. Methods: In this cohort study, documents of 1550 patients with colorectal cancer between 2002 and 2020 from Omid hospital and Emam Reza hospital (Mashhad, Iran) databases were evaluated, retrospectively. The multivariable logistic regression and Cox proportional hazard regressions were used at the significance level of P < 0.05. Results: Nine hundred twenty patients included in the current study. Most of patients were categorized as normal weight (38.91%). The prevalence of underweight and overweight/obese were 26.19% and 34.9%, respectively. There was no significant difference in the overall survival (OS) and disease-free survival (DFS) based on BMI (OS: 108.2 ± 7.0 months for underweight, 124.0 ± 6.2 months for normal weight, and 130.9 ± 4.5 months for overweight/obese patients; P = 0.2 and DFS: 97.0 ± 6.5, 110.0 ± 5.6, and 113.7 ± 5.0, respectively; P = 0.3). Conclusions: The BMI had no significant effect on long-term outcomes of patients with colorectal cancer. However, there was an insignificant trend to better outcome in patients with higher BMI comparing the underweight group.

A novel decision model to predict the impact of weight management interventions: The Core Obesity Model

Aims

Models are needed to quantify the economic implications of obesity in relation to health outcomes and health-related quality of life. This report presents the structure of the Core Obesity Model (COM) and compare its predictions with the UK clinical practice data.

Materials and methods

The COM is a Markov, closed-cohort model, which expands on earlier obesity models by including prediabetes as a risk factor for type 2 diabetes (T2D), and sleep apnea and cancer as health outcomes. Selected outcomes predicted by the COM were compared with observed event rates from the Clinical Practice Research Datalink-Hospital Episode Statistics (CPRD-HES) study. The importance of baseline prediabetes prevalence, a factor not taken into account in previous economic models of obesity, was tested in a scenario analysis using data from the 2011 Health Survey of England.

Results

Cardiovascular (CV) event rates predicted by the COM were well matched with those in the CPRD-HES study (7.8-8.5 per 1000 patient-years across BMI groups) in both base case and scenario analyses (8.0-9.4 and 8.6-9.9, respectively). Rates of T2D were underpredicted in the base case (1.0-7.6 vs. 2.1-22.7) but increased to match those observed in CPRD-HES for some BMI groups when a prospectively collected prediabetes prevalence was used (2.7-13.1). Mortality rates in the CPRD-HES were consistently higher than the COM predictions, especially in higher BMI groups.

Conclusions

The COM predicts the occurrence of CV events and T2D with a good degree of accuracy, particularly when prediabetes is included in the model, indicating the importance of considering this risk factor in economic models of obesity.

The impact of anthropometric parameters on colorectal cancer prognosis: A systematic review and meta-analysis

BACKGROUND & AIMS

Our study aims to clarify the relationship between weight parameters and colorectal cancer outcomes.

METHODS

NCBI, Embase, Cochrane, and Web of Science were searched from inception to December 2019. Studies reporting colorectal cancer (CRC) mortality, recurrence, disease-free survival, overall survival, overall mortality stratified by pre-diagnosis BMI or post-diagnosis weight change, were included in the analysis. Random effects analysis was performed for all outcomes, with heterogeneity assessed by the I² statistic.

RESULTS

Our meta-analysis included 45 studies encompassing 607,266 patients. Obesity was associated with increased odds of overall mortality and CRC-specific mortality compared to normal weight (p < 0.001). Patients with underweight BMI had increased odds of CRC-specific mortality compared to normal BMI but were not significantly different from obese BMI.

CONCLUSIONS

Obese and underweight BMI are associated with increased CRC-specific and overall mortality compared to normal BMI. Long term prognosis was similar for patients with obese and underweight BMI.

The association between the adapted dietary inflammatory index and colorectal cancer recurrence and all-cause mortality

BACKGROUND & AIMS

The inflammatory potential of the diet has been linked to colorectal cancer (CRC) development and mortality. However, it is unknown whether it is also associated with CRC recurrence. Therefore, the aim of this study was to investigate the associations between the inflammatory potential of the diet and plasma inflammation markers as well as recurrence and all-cause mortality in CRC patients.

METHODS

Data of the Colorectal cancer, Observational, LONgitudinal (COLON) study, a prospective cohort study, was used. Dietary intake, assessed using a semi-quantitative food frequency questionnaire, was available for 1478 patients at diagnosis and for 1334 patients six months after diagnosis. Dietary intake data were used to calculate the adapted dietary inflammatory index (ADII). Data about cancer recurrence and all-cause mortality, were assessed through linkage with the Netherlands Cancer Registry and the Municipal Personal Records Database, respectively. The association between the ADII (continuous) and inflammation markers (Interleukin (IL)6, IL8, IL10, Tumor Necrosis Factor (TNF)α, high sensitivity C-reactive protein (hsCRP) and a summary inflammatory z-score), measured with a multiplex assay using electrochemiluminiscence detection, was assessed using quantile regression analyses. Restricted cubic splines (RCS) analyses and multivariable Cox proportional hazard models were used to explore the relationship between the ADII and CRC outcomes.

RESULTS

During a median follow-up time of 3.2 years (Interquartile range (IQR) 2.0-4.1) for recurrence and 4.8 years (IQR 3.5-5.9) for all-cause mortality, 228 recurrences and 279 deaths occurred. A more pro-inflammatory diet at diagnosis as well as six months after diagnosis was associated with higher levels of TNFα, hsCRP and the summary inflammatory z-score. Results of RCS showed no relationship between the ADII and CRC outcomes at both time points. Also results of the Cox proportional hazard models showed no associations between the ADII at both time points and recurrence (HR (95%CI) 0.98 (0.94-1.04) & 0.96 (0.91-1.02) or all-cause mortality (HR (95%CI) 1.03 (0.98-1.07) & 1.00 (0.95-1.05)).

CONCLUSION

Our study did not show an association between the ADII and recurrence and all-cause mortality in CRC patients. Further research should also take into account molecular tumor subtypes, as the effect of the inflammatory potential of the diet on cancer recurrence and mortality is more likely to be present in tumors with an inflammatory signature.

CLINICAL TRIAL REGISTRY NUMBERS AND WEBSITE

The colon study: NCT03191110; clinical trials.gov.

To do or not to do - a survey study on factors associated with participating in the Danish screening program for colorectal cancer

Background

Screening programs for colorectal cancer (CRC) exist in many countries, and with varying participation rates. The present study aimed at identifying socio-demographic factors for accepting a cost-free screening offer for CRC in Denmark, and to study if more people would accept the screening offer if the present fecal test was replaced by a blood test.

Methods

We used a cross-sectional survey design based on a representative group of 6807 Danish citizens aged 50–80 years returning a fully answered web-based questionnaire with socio-demographic data added from national registries. Data were analyzed in STATA and based on bivariate analyses followed by regression models.

Results

Danes in general have a high level of lifetime participation (+ 80%) in the national CRC screening program. The results of the stepwise logistic regression model to predict CRC screening participation demonstrated that female gender, higher age, higher income, and moderate alcohol intake were positively associated with screening participation, whereas a negative association was observed for higher educational attainment, obesity, being a smoker, and higher willingness to take health risks. Of the 1026 respondents not accepting the screening offer, 61% were willing to reconsider their initial negative response if the fecal sampling procedure were replaced by blood sampling.

Conclusion

The CRC screening program intends to include the entire population within a certain at-risk age group. However, individual factors (e.g. sex, age obesity, smoking, risk aversity) appear to significantly affect willingness to participate in the screening program. From a preventive perspective, our findings indicate the need for a more targeted approach trying to reach these groups.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-020-06023-6.

Gut Microbiota and Colorectal Cancer Development: A Closer Look to the Adenoma-Carcinoma Sequence

There is wide evidence that CRC could be prevented by regular physical activity, keeping a healthy body weight, and following a healthy and balanced diet. Many sporadic CRCs develop via the traditional adenoma-carcinoma pathway, starting as premalignant lesions represented by conventional, tubular or tubulovillous adenomas. The gut bacteria play a crucial role in regulating the host metabolism and also contribute to preserve intestinal barrier function and an effective immune response against pathogen colonization. The microbiota composition is different among people, and is conditioned by many environmental factors, such as diet, chemical exposure, and the use of antibiotic or other medication. The gut microbiota could be directly involved in the development of colorectal adenomas and the subsequent progression to CRC. Specific gut bacteria, such as Fusobacterium nucleatum, Escherichia coli, and enterotoxigenic Bacteroides fragilis, could be involved in colorectal carcinogenesis. Potential mechanisms of CRC progression may include DNA damage, promotion of chronic inflammation, and release of bioactive carcinogenic metabolites. The aim of this review was to summarize the current knowledge on the role of the gut microbiota in the development of CRC, and discuss major mechanisms of microbiota-related progression of the adenoma-carcinoma sequence.

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

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

Bariatric Surgery Is Associated with a Recent Temporal Increase in Colorectal Cancer Resections, Most Pronounced in Adults Below 50 Years of Age

BACKGROUND

Colorectal cancer incidence is rising in adults < 50 years old, possibly due to obesity. Having bariatric surgery (BRS) should hypothetically reduce this trend, but data are limited. This study compared trends of colorectal cancer (CRC) versus other obesity-related gastrointestinal cancers (OGCs) between morbidly obese and post-BRS subjects.

MATERIAL AND METHODS

This retrospective cohort study investigated OGC resection trends using the 2006-2013 National Inpatient Sample. Patients with prior BRS and non-BRS controls with body mass index ≥ 40 kg/m² were included (n = 30,279 total). We divided OGCs into CRC and non-CRC OGCs (esophageal, stomach, liver, gallbladder, and pancreas). We calculated OGC resection trends in patients < 50 and ≥ 50 years old using the average annual percent change (AAPC).

RESULTS

BRS patients with OGCs were younger (59.3 vs 62.3 years old), with more female gender (77.4% vs 57.1%) and White race (72.6% vs 67%) compared with controls (p < 0.05). The number of CRC resections increased across all ages in 2006-2013, especially rectal cancer for BRS patients (AAPC + 19.8%, p = 0.04). The steepest rise in early-onset CRC resections was after BRS versus a lesser increase in morbid obesity controls (AAPC + 18.7% and + 13.7%, respectively, p < 0.001). In contrast, non-CRC OGCs increased in our controls but not post-BRS. In a sensitivity analysis, estimated CRC incidence trends also increased post-BRS despite adjusting for increasing BRS prevalence.

CONCLUSION

Our findings suggest that bariatric surgery is associated with a persistent increase in early-onset CRC trends. Studies are warranted to validate our results and test the impact of bariatric surgery on early-onset CRC biological mechanisms.

Linking Obesity with Colorectal Cancer: Epidemiology and Mechanistic Insights

The incidence of obesity and colorectal cancer (CRC) has risen rapidly in recent decades. More than 650 million obese and 2 billion overweight individuals are currently living in the world. CRC is the third most common cancer. Obesity is regarded as one of the key environmental risk factors for the pathogenesis of CRC. In the present review, we mainly focus on the epidemiology of obesity and CRC in the world, the United States, and China. We also summarize the molecular mechanisms linking obesity to CRC in different aspects, including nutriology, adipokines and hormones, inflammation, gut microbiota, and bile acids. The unmet medical needs for obesity-related CRC are still remarkable. Understanding the molecular basis of these associations will help develop novel therapeutic targets and approaches for the treatment of obesity-related CRC.

Recurrence Rate in a Patient Treated with Colon Resection Followed by Chemotherapy in Comparison to a Patient Treated with Colon Resection without Chemotherapy

Given that colon cancer is one of the most prevalent cancers worldwide, it is essential to employ strategies to try to reduce its incidence and recurrence rate. Though colon cancer is a sporadic disease in the vast majority of cases, multiple risk factors are linked to this disease, namely, obesity and cigarette smoking. Additionally, not many studies have been done in Saudi Arabia studying the recurrence rate of colon cancer. Therefore, we conducted a retrospective cohort study at King Khalid Hospital, King Abdulaziz Medical City, National Guard Health Affairs (NGHA), Jeddah, Saudi Arabia to investigate the recurrence rate of colon cancer in patients treated with complete colon resection followed by chemotherapy versus patients treated with colon resection alone via electronic and paper medical records. A total of 120 patients were included in this study; 61 were males (50.8%) and 59 were females (49.2%). According to our findings, the recurrence rate in patients who underwent surgical resection with adjuvant chemotherapy was 15.6% (n = 10), while the recurrence rate in patients with surgery alone was 21.4% (n = 12). Cancer recurrence is associated with significant morbidity and mortality. Therefore, further studies should be done to investigate the recurrence rate in patients with risk factors to identify and deal with the causes of recurrence.

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.

Risk Factors for Colorectal Cancer in Korea: A Population-Based Retrospective Cohort Study

Purpose

The incidence of colorectal cancer in Korea has recently increased, making it the second most common cancer in men and the third most common cancer in women. Risk factors for colorectal cancer have been studied worldwide, but risk factors specific for the Korean population have not been established. In this study, we investigated incidence trends and risk factors of colorectal cancer in Korea.

Methods

A total of 8,846,749 subjects were included. Colorectal cancer incidence was investigated using Korea National Health Insurance Service claim data from 2004 to 2014. Colorectal cancer diagnoses were obtained by evaluating colorectal cancer diagnostic codes and the cancer registry for cost sharing. Risk factor identification for colorectal cancer was obtained from National Health Examination data from 2004 to 2005. Cox proportional hazard model statistical analysis was used to determine risk factors of colorectal cancer.

Results

The incidence of colorectal cancer gradually increased from 2006 to 2014 (from 45.4/100,000 to 54.5/100,000). There was a predominance among men (1.47:1), but incidence trends were similar in both sexes. Old age, high body mass index, and no history of colonoscopy were identified as risk factors in both sexes. High fasting blood glucose, familial history of cancer, frequent alcohol intake, and current smoker were identified as risk factors, especially in men.

Conclusion

The incidence of colorectal cancer has been increasing in Korea. Colonoscopy screening was a protective factor for colorectal cancer, and active use of colonoscopy may reduce incidence. Early diagnosis and care are important, particularly for the high-risk group.

Longitudinal associations between BMI change and the risks of colorectal cancer incidence, cancer-relate and all-cause mortality among 81,388 older adults : BMI change and the risks of colorectal cancer incidence and mortality

Background

It remains controversial whether weight change could influence the risks of colorectal cancer (CRC) and mortality. This study aimed to quantify the associations between full-spectrum changes in body mass index (BMI) and the risks of colorectal cancer (CRC) incidence, cancer-related and all-cause mortality among midlife to elder population.

Methods

A total of 81,388 participants who were free of cancer and aged 55 to 74 years from the Prostate, Lung, Colorectal, and Ovarian (PLCO) screening program were involved. The percentage change of BMI was calculated as (BMI in 2006 - BMI at baseline)/BMI at baseline, and was categorized into nine groups: decrease (≥ 15.0%, 10.0–14.9%, 5.0–9.9%, 2.5–4.9%), stable (decrease/increase < 2.5%), increase (2.5–4.9%, 5.0–9.9%, 10.0–14.9%, ≥ 15.0%). The associations between percentage change in BMI from study enrolment to follow-up (median: 9.1 years) and the risks of CRC and mortality were evaluated using Cox proportional hazard regression models.

Results

After 2006, there were 241 new CRC cases, 648 cancer-related deaths, and 2361 all-cause deaths identified. Overall, the associations between BMI change and CRC incidence and cancer-related mortality, respectively, were not statistically significant. Compared with participants whose BMI were stable, individuals who had a decrease in BMI were at increased risk of all-cause mortality, and the HRs were 1.21 (95% CI: 1.03–1.42), 1.65 (95% CI: 1.44–1.89), 1.84 (95% CI: 1.56–2.17), and 2.84 (95% CI: 2.42–3.35) for 2.5–4.9%, 5.0–9.9%, 10.0–14.9%, and ≥ 15.0% decrease in BMI, respectively. An L-shaped association between BMI change and all-cause mortality was observed. Every 5% decrease in BMI was associated with a 27% increase in the risk of all-cause mortality (HR = 1.27, 95% CI: 1.22–1.31, p < 0.001). The results from subgroups showed similar trends.

Conclusions

A decrease in BMI more than 5% shows a significantly increased risk of all-cause mortality among older individuals; but no significant association between increase in BMI and all-cause mortality. These findings emphasize the importance of body weight management in older population, and more studies are warranted to evaluate the cause-and-effect relationship between changes in BMI and cancer incidence/mortality.

Risk factors for colorectal cancer significantly vary by anatomic site

Objective

To conduct an anatomic site-specific case–control study of candidate colorectal cancer (CRC) risk factors.

Design

Case–control study of US veterans with >1 colonoscopy during 1999–2011. Cases had cancer registry-identified CRC at colonoscopy, while controls were CRC free at colonoscopy and within 3 years of colonoscopy. Primary outcome was CRC, stratified by anatomic site: proximal, distal, or rectal. Candidate risk factors included age, sex, race/ethnicity, body mass index, height, diabetes, smoking status, and aspirin exposure summarised by adjusted ORs and 95% CIs.

Results

21 744 CRC cases (n=7017 rectal; n=7039 distal; n=7688 proximal) and 612 646 controls were included. Males had significantly higher odds relative to females for rectal cancer (OR=2.84, 95% CI 2.25 to 3.58) than distal cancer (OR=1.84, 95% CI 1.50 to 2.24). Relative to whites, blacks had significantly lower rectal cancer odds (OR=0.88, 95% CI 0.82 to 0.95), but increased distal (OR=1.27, 95% CI 1.19 to 1.37) and proximal odds (OR=1.62, 95% CI 1.52 to 1.72). Diabetes prevalence was more strongly associated with proximal (OR=1.29, 95% CI 1.22 to 1.36) than distal (OR=1.15, 95% CI 1.08 to 1.22) or rectal cancer (OR=1.12, 95% CI 1.06 to 1.19). Current smoking was more strongly associated with rectal cancer (OR=1.81, 95% CI 1.68 to 1.95) than proximal cancer (OR=1.53, 95% CI 1.43 to 1.65) or distal cancer (OR=1.46, 95% CI 1.35 to 1.57) compared with never smoking. Aspirin use was significantly more strongly associated with reduced rectal cancer odds (OR=0.71, 95% CI 0.67 to 0.76) than distal (OR=0.85, 95% CI 0.81 to 0.90) or proximal (OR=0.91, 95% CI 0.86 to 0.95).

Conclusion

Candidate CRC risk factor associations vary significantly by anatomic site. Accounting for site may enable better insights into CRC pathogenesis and cancer control strategies.

Weight change since age 20 and incident risk of obesity-related cancer in Japan: a pooled analysis of the Miyagi Cohort Study and the Ohsaki Cohort Study

It is unclear whether weight change during adulthood affects the risk of obesity-related cancers such as those of the esophagus, colorectum, pancreas, breast, endometrium, and kidney among Japanese, where obesity is less frequent and less severe. We examined the association between weight change during adulthood and the risk of obesity-related cancer among Japanese by conducting a pooled analysis of two prospective studies of residents in Miyagi Prefecture, Japan. A total of 78,743 persons (40,422 women and 38,321 men) aged 40-79 years participated in the Miyagi Cohort Study in 1990 and in the Ohsaki Cohort Study in 1994. Weight change since age 20 was divided into four categories (weight loss; stable weight; moderate weight gain; high weight gain). Cox proportional hazards regression analysis was used to estimate the multivariate hazard ratios (HRs) and 95% confidence intervals (CIs) for obesity-related cancer incidence. During 1,057,899 person-years of follow up, 4,467 cases of obesity-related cancer (women; 1,916 cases, men; 2,551cases) were identified. In women, compared to the stable weight, weight gain was associated with an increased risk of obesity-related cancer (moderate weight gain; HRs = 1.10, 95%CIs: 0.97-1.26, high weight gain; HRs = 1.29, 95%CIs: 1.14-1.47). The results indicate that weight gain since age 20 was associated with a significantly increased risk of obesity-related cancer among Japanese women. By contrast, in men, our study found that weight change is not associated with the incidence of obesity-related cancer.

Global patterns in excess body weight and the associated cancer burden

The prevalence of excess body weight and the associated cancer burden have been rising over the past several decades globally. Between 1975 and 2016, the prevalence of excess body weight in adults-defined as a body mass index (BMI) ≥ 25 kg/m² -increased from nearly 21% in men and 24% in women to approximately 40% in both sexes. Notably, the prevalence of obesity (BMI ≥ 30 kg/m² ) quadrupled in men, from 3% to 12%, and more than doubled in women, from 7% to 16%. This change, combined with population growth, resulted in a more than 6-fold increase in the number of obese adults, from 100 to 671 million. The largest absolute increase in obesity occurred among men and boys in high-income Western countries and among women and girls in Central Asia, the Middle East, and North Africa. The simultaneous rise in excess body weight in almost all countries is thought to be driven largely by changes in the global food system, which promotes energy-dense, nutrient-poor foods, alongside reduced opportunities for physical activity. In 2012, excess body weight accounted for approximately 3.9% of all cancers (544,300 cases) with proportion varying from less than 1% in low-income countries to 7% or 8% in some high-income Western countries and in Middle Eastern and Northern African countries. The attributable burden by sex was higher for women (368,500 cases) than for men (175,800 cases). Given the pandemic proportion of excess body weight in high-income countries and the increasing prevalence in low- and middle-income countries, the global cancer burden attributable to this condition is likely to increase in the future. There is emerging consensus on opportunities for obesity control through the multisectoral coordinated implementation of core policy actions to promote an environment conducive to a healthy diet and active living. The rapid increase in both the prevalence of excess body weight and the associated cancer burden highlights the need for a rejuvenated focus on identifying, implementing, and evaluating interventions to prevent and control excess body weight.

Mediation of associations between adiposity and colorectal cancer risk by inflammatory and metabolic biomarkers

Inflammation and hyperinsulinemia may drive associations between adiposity and colorectal cancer (CRC) risk, but few studies have examined this hypothesis using mediation analysis. We used inverse odds ratio weighting and logistic regression to calculate odds ratios (OR) and 95% confidence intervals (CI) for estimated total effects (OR^TE ) of body mass index, waist circumference, and adult weight gain on CRC risk, and estimated effects operating through seven inflammatory and metabolic biomarkers (natural indirect effect; OR^NIE ) or through paths independent of these biomarkers (natural direct effect; OR^NDE ) among 209 CRC cases and 382 matched controls nested within the Health Professionals Follow-up Study, a prospective cohort of male health professionals. A one-interquartile range (IQR) increase in body mass index (3.6 kg/m² ) was associated with an OR^TE of 1.40 (95% CI: 1.13, 1.73), which decomposed into an OR^NIE of 1.26 (95% CI: 0.97, 1.52) and an OR^NDE of 1.11 (0.87, 1.42), with possibly stronger mediation by these biomarkers for adult weight gain (IQR = 10.4 kg; OR^TE = 1.32 [95% CI: 1.06, 1.64]; OR^NIE = 1.47 [95% CI: 1.01, 1.81]; OR^NDE = 0.89 [95% CI: 0.72, 1.11]), but no mediation for waist circumference. Mediation appeared to be stronger for the metabolic biomarkers than the inflammatory biomarkers. Inflammatory and metabolic mechanisms may mediate associations between both body mass index and adult weight gain with CRC risk.

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

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

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

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

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

Cancers Potentially Preventable through Excess Weight Reduction in Germany in 2010

OBJECTIVE

In order to quantify the preventive potential of body weight reduction in Germany, population-attributable risks (PARs) were estimated for 13 cancer types.

METHODS

PARs were calculated using body weight prevalence from a nationwide survey from 1998, cancer incidence estimates for 2010 from cancer registry data and relative risk estimates from published meta-analyses. Three counterfactual scenarios were evaluated: reducing BMI to maximally 21 kg/m² (main analysis) and weight reductions among overweight and obese persons of 5% and 10%.

RESULTS

An estimated 9% of all incident cancer cases in Germany - 40,748 cases - could be attributed to excess body weight in 2010. The highest proportions were estimated for endometrial cancer (48%) and oesophageal adenocarcinoma (48% for women, 46% for men). The largest case numbers were estimated for postmenopausal breast (9,081 cases), colorectal (8,002 cases among men, 3,297 cases among women) and endometrial cancer (5,468 cases). The additional counterfactual scenarios suggested that weight reductions of 5% and 10% could prevent 5,572 cases and 11,427 cases, respectively.

CONCLUSIONS

In Germany there is a considerable preventive potential for cancers associated with excess body weight. Efforts to prevent further weight gain and encourage weight loss should be promoted.

Progress in primary prevention of colorectal cancer

Colorectal cancer (CRC) is one of the most common malignant tumors in the digestive tract, with high incidence and mortality. Most of CRC cases are diagnosed at the late stage, and the treatment effect is therefore poor. Thus, the prevention of CRC is particularly important. There have been many studies on the prevention of CRC in recent years. This paper will summarize the latest research on the primary prevention of CRC.

Midlife weight gain is a risk factor for obesity-related cancer

Background

Overweight and diabetes are known cancer risk factors. This study examines independent and combined effects of weight gain and metabolic dysfunction during middle-adult years on obesity-related cancer risk.

Methods

Subjects (n = 3850) aged 45–69 years at exams 3–5 in the Framingham Offspring Study were classified according to current and prior (~14 years earlier) weight status, interim weight change and prevalent metabolic dysfunction. Cancer risk among subjects who were overweight at baseline and remained overweight, as well as those who became overweight during follow-up, was compared with risk among normal-weight individuals.

Results

Gaining ≥0.45 kg (≥1.0 pound)/year (vs. maintaining stable weight) over ~14 years increased cancer risk by 38% (95% confidence interval (CI), 1.09, 1.76); combined with metabolic dysfunction, weight gain increased cancer risk by 77% (95% CI, 1.21, 2.59). Compared with non-overweight adults, men and women who became overweight during midlife had 2.18-fold and 1.60-fold increased cancer risks; those who were overweight from baseline had non-statistically significant 28 and 33% increased cancer risks, respectively, despite having a midlife body mass index that was 3.4 kg/m² higher than those who gained weight later.

Conclusion

Midlife weight gain was a strong cancer risk factor. This excess risk was somewhat stronger among those with concurrent metabolic dysfunction.

Adult weight gain and colorectal adenomas-a systematic review and meta-analysis

Background

Colorectal adenomas are known as precursors for the majority of colorectal carcinomas. While weight gain during adulthood has been identified as a risk factor for colorectal cancer, the association is less clear for colorectal adenomas. We conducted a systematic review and meta-analysis to quantify the evidence on this association.

Methods

We searched Medline up to September 2016 to identify observational (prospective, cross-sectional and retrospective) studies on weight gain during adulthood and colorectal adenoma occurrence and recurrence. We conducted meta-analysis on high weight gain versus stable weight, linear and non-linear dose-response meta-analyses to analyze the association. Summary odds ratios (OR) and 95% confidence intervals (95% CI) were estimated using a random effects model.

Results

For colorectal adenoma occurrence, the summary OR was 1.39 (95% CI: 1.17-1.65; I2: 43%, N = 9 studies, cases = 5507) comparing high (midpoint: 17.4 kg) versus stable weight gain during adulthood and with each 5 kg weight gain the odds increased by 7% (2%-11%; I2: 65%, N = 7 studies). Although there was indication of non-linearity (Pnon-linearity < 0.001) there was an increased odds of colorectal adenoma throughout the whole range of weight gain. Three studies were identified investigating the association between weight gain and colorectal adenoma recurrence and data were limited to draw firm conclusions.

Conclusions

Even a small amount of adult weight gain was related to a higher odds of colorectal adenoma occurrence. Our findings add to the benefits of weight control in adulthood regarding colorectal adenoma occurrence, which might be relevant for early prevention of colorectal cancer.

Genetically predicted high body mass index is associated with increased gastric cancer risk

Epidemiological studies have linked body mass index (BMI) with risk of gastrointestinal cancers. However, for gastric cancer, the relationship is more controversial. In particular, it is unclear whether the observed association is due to confounding or bias inherent in conventional observational studies. To investigate whether BMI is causally associated with gastric cancer risk, we applied Mendelian randomization using individual-level data from 2631 gastric cancer cases and 4373 cancer-free controls. We derived a weighted genetic risk score (wGRS) using 37 BMI-associated genetic variants as an instrumental variable. We used logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI) for associations between genetically predicted BMI and gastric cancer risk. We observed that higher genetically determined BMI was associated with increased gastric cancer risk (per standard deviation (SD) increase in the wGRS: OR=1.07, 95% CI: 1.02-1.13, P=4.94 × 10^-3). Compared with individuals in the bottom tertile of the BMI wGRS, those in the top tertile had 1.14-fold (95% CI: 1.01-1.29) increased risk of developing gastric cancer. Sensitivity analyses using alternative causal inference measures demonstrated consistent association. Our study indicated that genetically high BMI was associated with increased gastric cancer risk, suggesting that high BMI may have a causal role in the etiology of gastric cancer.

Apc inactivation, but not obesity, synergizes with Pten deficiency to drive intestinal stem cell-derived tumorigenesis

Obesity is a major risk factor for colorectal cancer and can accelerate Lgr5+ intestinal stem cell (ISC)-derived tumorigenesis after the inactivation of Apc However, whether non-canonical pathways involving PI3K-Akt signaling in ISCs can lead to tumor formation, and if this can be further exacerbated by obesity is unknown. Despite the synergy between Pten and Apc inactivation in epithelial cells on intestinal tumor formation, their combined role in Lgr5+-ISCs, which are the most rapidly dividing ISC population in the intestine, is unknown. Lgr5+-GFP mice were provided low-fat diet (LFD) or high-fat diet (HFD) for 8 months, and the transcriptome was evaluated in Lgr5+-ISCs. For tumor studies, Lgr5+-GFP and Lgr5+-GFP-Pten^flox/flox mice were tamoxifen treated to inactivate Pten in ISCs and provided LFD or HFD until 14-15 months of age. Finally, various combinations of Lgr5+-ISC-specific, Apc- and Pten-deleted mice were generated and evaluated for histopathology and survival. HFD did not overtly alter Akt signaling in ISCs, but did increase other metabolic pathways. Pten deficiency, but not HFD, increased BrdU-positive cells in the small intestine (P < 0.05). However, combining Pten and Apc deficiency synergistically increased proliferative markers, tumor pathology and mortality, in a dose-dependent fashion (P < 0.05). In summary, we show that HFD alone fails to drive Akt signaling in ISCs and that Pten deficiency is dispensable as a tumor suppressor in Lgr5+-ISCs. However, combining Pten and Apc deficiency in ISCs synergistically increases proliferation, tumor formation and mortality. Thus, aberrant Wnt/β-catenin, rather than PI3K-Akt signaling, is requisite for obesity to drive Lgr5+ ISC-derived tumorigenesis.

Metabolic Mediators of the Association Between Adult Weight Gain and Colorectal Cancer: Data From the European Prospective Investigation into Cancer and Nutrition (EPIC) Cohort

Evidence indicates that gaining weight in adult life is associated with an elevated risk of colorectal cancer; however, biological mechanisms that may explain this association remain unclear. We evaluated the mediation effect of 20 different biomarkers on the relationship between adult weight gain and colorectal cancer, using data from a prospective nested case-control study of 452 incident cases diagnosed between 1992 and 2003 and matched within risk sets to 452 controls within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. The proportions of mediated effects (%) were estimated on the basis of differences in percent effect changes in conditional logistic regression models with and without additional adjustment for individual biomarkers. Greater adult weight gain (≥300 g/year vs. <300 g/year) was associated with a higher risk of colon cancer (multivariable-adjusted relative risk = 1.54, 95% confidence interval: 1.07, 2.24) but not rectal cancer (relative risk = 1.07, 95% confidence interval: 0.68, 1.66). This association was accounted for mostly by attained waist circumference (reduction of 61%) and by the biomarkers soluble leptin receptor (reduction of 43%) and glycated hemoglobin (reduction of 28%). These novel data suggest that the observed association between adult weight gain and colon cancer could be primarily explained by attained abdominal fatness and biomarkers of metabolic dysfunction.

Adiposity and cancer at major anatomical sites: umbrella review of the literature

Objective To evaluate the strength and validity of the evidence for the association between adiposity and risk of developing or dying from cancer.Design Umbrella review of systematic reviews and meta-analyses.Data sources PubMed, Embase, Cochrane Database of Systematic Reviews, and manual screening of retrieved references.Eligibility criteria Systematic reviews or meta-analyses of observational studies that evaluated the association between indices of adiposity and risk of developing or dying from cancer.Data synthesis Primary analysis focused on cohort studies exploring associations for continuous measures of adiposity. The evidence was graded into strong, highly suggestive, suggestive, or weak after applying criteria that included the statistical significance of the random effects summary estimate and of the largest study in a meta-analysis, the number of cancer cases, heterogeneity between studies, 95% prediction intervals, small study effects, excess significance bias, and sensitivity analysis with credibility ceilings.Results 204 meta-analyses investigated associations between seven indices of adiposity and developing or dying from 36 primary cancers and their subtypes. Of the 95 meta-analyses that included cohort studies and used a continuous scale to measure adiposity, only 12 (13%) associations for nine cancers were supported by strong evidence. An increase in body mass index was associated with a higher risk of developing oesophageal adenocarcinoma; colon and rectal cancer in men; biliary tract system and pancreatic cancer; endometrial cancer in premenopausal women; kidney cancer; and multiple myeloma. Weight gain and waist to hip circumference ratio were associated with higher risks of postmenopausal breast cancer in women who have never used hormone replacement therapy and endometrial cancer, respectively. The increase in the risk of developing cancer for every 5 kg/m2 increase in body mass index ranged from 9% (relative risk 1.09, 95% confidence interval 1.06 to 1.13) for rectal cancer among men to 56% (1.56, 1.34 to 1.81) for biliary tract system cancer. The risk of postmenopausal breast cancer among women who have never used HRT increased by 11% for each 5 kg of weight gain in adulthood (1.11, 1.09 to 1.13), and the risk of endometrial cancer increased by 21% for each 0.1 increase in waist to hip ratio (1.21, 1.13 to 1.29). Five additional associations were supported by strong evidence when categorical measures of adiposity were included: weight gain with colorectal cancer; body mass index with gallbladder, gastric cardia, and ovarian cancer; and multiple myeloma mortality.Conclusions Although the association of adiposity with cancer risk has been extensively studied, associations for only 11 cancers (oesophageal adenocarcinoma, multiple myeloma, and cancers of the gastric cardia, colon, rectum, biliary tract system, pancreas, breast, endometrium, ovary, and kidney) were supported by strong evidence. Other associations could be genuine, but substantial uncertainty remains. Obesity is becoming one of the biggest problems in public health; evidence on the strength of the associated risks may allow finer selection of those at higher risk of cancer, who could be targeted for personalised prevention strategies.

Diet-induced weight loss leads to a switch in gene regulatory network control in the rectal mucosa

BACKGROUND

Weight loss may decrease risk of colorectal cancer in obese individuals, yet its effect in the colorectum is not well understood. We used integrative network modeling, Passing Attributes between Networks for Data Assimilation, to estimate transcriptional regulatory network models from mRNA expression levels from rectal mucosa biopsies measured pre- and post-weight loss in 10 obese, pre-menopausal women.

RESULTS

We identified significantly greater regulatory targeting of glucose transport pathways in the post-weight loss regulatory network, including "regulation of glucose transport" (FDR=0.02), "hexose transport" (FDR=0.06), "glucose transport" (FDR=0.06) and "monosaccharide transport" (FDR=0.08). These findings were not evident by gene expression analysis alone. Network analysis also suggested a regulatory switch from NFΚB1 to MAX control of MYC post-weight loss.

CONCLUSIONS

These network-based results expand upon standard gene expression analysis by providing evidence for a potential mechanistic alteration caused by weight loss.

Change in weight and waist circumference and risk of colorectal cancer: results from the Melbourne Collaborative Cohort Study

BACKGROUND

Studies reporting the association between change in weight or body mass index during midlife and risk of colorectal cancer have found inconsistent results, and only one study to date has reported the association between change in waist circumference (a measure of central adiposity) and risk of colorectal cancer.

METHODS

We investigated the association between risk of colorectal cancer and changes in directly measured waist circumference and weight from baseline (1990-1994) to wave 2 (2003-2007). Cox regression, with age as the time metric and follow-up starting at wave 2, adjusted for covariates selected from a causal model, was used to estimate the Hazard Ratios (HRs) and 95 % Confidence Intervals (CIs) for the change in waist circumference and weight in relation to risk of colorectal cancer.

RESULTS

A total of 373 cases of colorectal cancer were diagnosed during an average 9 years of follow-up of 20,605 participants. Increases in waist circumference and weight were not associated with the risk of colorectal cancer (HR per 5 cm increase in waist circumference = 1.02; 95 % CI: 0.95, 1.10; HR per 5 kg increase in weight = 0.93; 0.85, 1.02). For individuals with a waist circumference at baseline that was less than the sex-specific mean value there was a slight increased risk of colorectal cancer associated with a 5 cm increase in waist circumference at wave 2 (HR = 1.08; 0.97, 1.21).

CONCLUSION

Increases in waist circumference and weight during midlife do not appear to be associated with the risk of colorectal cancer.

Obesity and Colorectal Cancer

There is strong evidence that modifiable lifestyle factors such as obesity play a key role in colorectal carcinogenesis. Epidemiologic data have consistently reported a positive association between obesity and colorectal cancer. The relative risk associated with general obesity (as assessed by BMI) is higher in men than in women and for cancer of the colon than for cancer of the rectum. Abdominal obesity (as assessed by waist circumference (WC) or waist-to-hip ratio) is associated with an increased risk of colorectal cancer in both sexes, with stronger associations for cancer of the colon than for cancer of the rectum. Plausible biological mechanisms include insulin resistance, hyperinsulinemia, chronic inflammation, altered levels of growth factors, adipocytokines and steroid hormones. In addition to its effect on colorectal cancer incidence, obesity may play a role in colorectal cancer recurrence, treatment outcomes and survival. Understanding the effects of childhood and adolescent obesity and weight change over the life course in relation to future risk of colorectal cancer is incomplete but essential for targeted preventive recommendations. This chapter summarizes the current evidence on the relationship between obesity and colorectal cancer and colorectal adenoma, a common precursor lesion.