Obesity and risk of bladder cancer: a meta-analysis of cohort studies

Excess weight by degree and duration and cancer risk (ABACus2 consortium): a cohort study and individual participant data meta-analysis

Background

Elevated body mass index (BMI) ≥25 kg/m2 is a major preventable cause of cancer. A single BMI measure does not capture the degree and duration of exposure to excess BMI. We investigate associations between adulthood overweight-years, incorporating exposure time to BMI ≥25 kg/m2, and cancer incidence, and compare this with single BMI.

Methods

In this cohort study and individual participant data meta-analysis, we obtained data from the ABACus 2 Consortium, consisting of four US cohorts: Atherosclerosis Risk in Communities (ARIC) study (1987-2015), Women's Health Initiative (WHI; 1991 to 2005 [main study], to 2010 [Extension 1], and to 2020 [Extension 2]), Prostate, Lung, Colorectal, Ovarian Cancer Screening (PLCO) Trial (1993-2009), NIH-AARP Diet and Health Study (1996-2011), and one European cohort, the European Prospective Investigation into Cancer and Nutrition (EPIC; participants enrolled in 1990 and administrative censoring was centre-specific). Participants with at least 3 BMI measurements and complete cancer follow-up data were included. We calculated overweight-years: degree of overweight (BMI ≥25 kg/m2) multiplied by the duration of overweight (years). Using random effects two-stage individual participant data meta-analyses, associations between cancer and overweight-years, single BMI, cumulative overweight degree and duration, measured at the same time and captured over a median of 41 years in men and 39 years in women, were evaluated with Cox proportional hazards models. Models were age-adjusted or multivariable (MV) adjusted for baseline age, ethnicity, alcohol, smoking and hormone replacement therapy (HRT). Harrell's C-statistic of metrics were compared. This study is registered at PROSPERO, CRD42021238270.

Findings

720,210 participants, including 312,132 men and 408,078 women, were followed up for cancer incidence over a median 9.85 years (interquartile range (IQR) 8.03, 11.67) in men and 10.80 years (IQR 6.05, 15.55) in women. 12,959 men (4.15%) and 36,509 women (8.95%) were diagnosed with obesity-related cancer. Hazard ratios for obesity-related cancers in men, per 1 standard deviation (SD) overweight-years were 1.15 (95% CI: 1.14, 1.16, I2: 0) age-adjusted and 1.15 (95% CI: 1.13, 1.17, I2: 0%) MV-adjusted and per 1SD increment in single BMI were 1.17 (95% CI: 1.16, 1.18, I2: 0) age-adjusted and 1.16 (95% CI: 1.15, 1.18, I2: 0%) MV-adjusted. The HR for overweight-years in women per 1 SD increment was 1.08 (95% CI: 1.04, 1.13, I2: 82%) age-adjusted and 1.08 (95% CI: 1.04, 1.13, I2: 83%) MV-adjusted and per 1SD increment in single BMI was 1.10 (95% CI: 1.07, 1.14, I2: 72%) age-adjusted and 1.11 (95% CI: 1.07, 1.15, I2: 79%) MV-adjusted. C-statistics for overweight-years and single BMI for obesity-related cancers were 0.612 (95% CI: 0.578, 0.646) and 0.611 (95% CI: 0.578, 0.644) respectively for men and 0.566 (95% CI: 0.534, 0.598) and 0.573 (95% CI: 0.546, 0.600) for women.

Interpretation

Adulthood degree and duration of excess BMI were associated with cancer risk. Both factors should be considered in cancer prevention strategies and policies. This study only focused on adulthood exposure to excess BMI, so the minimal differences in the predictive performance between adiposity metrics may be due to underestimation of cumulative excess BMI exposure.

Funding

Cancer Research UK, the Manchester NIHR Biomedical Research Centre, the National Cancer Institute, the National Heart, Lung, and Blood Institute, National Institutes of Health, Department of Health and Human Services, U.S. Department of Health and Human Services, the Intramural Research Program of the National Cancer Institute, the International Agency for Research on Cancer, Imperial College London, European Commission (DG-SANCO), the Danish Cancer Society, Ligue Contre le Cancer, Institut Gustave-Roussy, Mutuelle Générale de l'Education Nationale, Institut National de la Santé et de la Recherche Médicale, Deutsche Krebshilfe, Deutsches Krebsforschungszentrum, German Federal Ministry of Education and Research, the Hellenic Health Foundation, Associazione Italiana per la Ricerca sul Cancro-AIRC-Italy and National Research Council, Dutch Ministry of Public Health, Welfare, and Sports, Netherlands Cancer Registry, LK Research Funds, Dutch Prevention Funds, Dutch Zorg Onderzoek Nederland, World Cancer Research Fund, Statistics Netherlands, Health Research Fund, Instituto de Salud Carlos III, regional Spanish governments of Andalucía, Asturias, Basque Country, Murcia, and Navarra, the Catalan Institute of Oncology, Swedish Cancer Society, Swedish Scientific Council, and Region Skåne and Region Västerbotten, and the Medical Research Council.

AST/ALT-to-platelet ratio (AARPRI) predicts gynaecological cancers: a 8-years follow-up study in 653 women

Non-alcoholic fatty liver disease (NAFLD), specifically liver steatosis and fibrosis with steatohepatitis (NASH), is often associated with visceral adiposopathy, whose pathogenetic features have been proposed as tumorigenic triggers. We performed a prospective analysis in 653 metabolic women to reveal any conditions that may predict and concur to cancer development during a 8-years period of follow-up. Among clinical and biochemical variables, only AST and non-invasive liver fibrosis scores (AARPRI, APRI, FIB-4, mFIB4) significantly distinguished cancer-developer women (n = 62, 9.5%) from those who did not develop cancer (p < 0.001). In ROC analysis, these scores also showed good sensitivity and specificity in differentiating women who developed cancer (all p < 0.001). We then calculated OR for these indexes finding that increased AARPRI was associated with the highest risk (OR = 6, p < 0.001) of gynaecological cancers development. We further validated these cut-off values in women who had developed other types of cancer, confirming that AARPRI is able to identify the risk for cancer development (OR = 5, p < 0.001). Our findings support the hypothesis that NAFLD, more than obesity per se, is directly associated with the clinical and pathogenic metabolic scenario of gynaecological cancers and encourage the use of liver fibrosis indexes to detect risk of cancer onset in women. Preventing adiposopathy and NAFLD through lifestyle and therapies may represent an instrumental strategy for cancer prevention and/or co-treatment in oncology.

Serum Leptin Receptor and the rs1137101 Variant of the LEPR Gene Are Associated with Bladder Cancer

Globally, bladder cancer (BC) is one of the ten most common tumors. Obesity is a worldwide problem associated with an increased BC risk. Considering that levels of leptin and/or its receptor are often deregulated in obese individuals, we hypothesized that they could contribute to BC. To test this hypothesis, we utilized a case-control study in which 116 patients with a confirmed diagnosis of BC and 116 controls were recruited. The serum levels of leptin and leptin receptor were measured. Patients and controls were also genotyped for SNPs in the LEP (rs7799039, rs791620, and rs2167270) and LEPR genes (rs1137100, rs1137101, and rs1805094). The univariate analysis indicated that BC patients had significantly higher levels of leptin and lower levels of leptin receptor (p < 0.05). Moreover, rs7799039 of LEP and rs1137101 of LEPR were associated with BC (p < 0.05). In the multivariate analysis, leptin receptor levels were protective (OR: 0.98, 95% CI = 0.97-0.99, p = 0.002) while the GG genotype of rs1137101 of LEPR increased BC risk (OR: 3.42, 95% CI = 1.27-9.20, p = 0.02). These findings highlight that lifestyle changes could be useful in preventing BC and that disturbances in energy metabolism could play a role in the pathobiology of BC.

Body composition as a predictor of oncological outcome in patients with non-muscle-invasive bladder cancer receiving intravesical instillation after transurethral resection of bladder tumor

Introduction

Body status, categorized as sarcopenia or obesity and assessed using body mass index and body composition, affects the outcome of bladder cancer patients. However, studies comparing disease progression, recurrence, or overall survival in patients with non-muscle-invasive bladder cancer (NMIBC) with different body compositions are lacking. Therefore, we conducted a retrospective study to identify the impact of body composition, sarcopenia, and obesity on the oncological prognosis of patients with NMIBC who underwent transurethral resection of bladder tumor (TURBT) with Bacillus Calmette-Guerin (BCG) intravesical instillation (IVI).

Methods

Patients with NMIBC who had undergone TURBT with adjuvant IVI with BCG from March 2005 to April 2021 were included. Body composition parameters were evaluated using computed tomography images of the third lumbar vertebrae and further categorized by sarcopenia and obesity. Oncological outcomes including recurrence-free survival (RFS), progression-free survival, and overall survival (OS) after treatment were analyzed.

Results

A total of 269 patients were enrolled. Subcutaneous adipose tissue (SAT) density was a significant predictor of RFS, whereas psoas muscle density was a significant predictor of OS in the multivariate analysis. Patients with sarcopenia but without obesity tolerated significantly fewer BCG IVIs than patients without sarcopenia or obesity. Patients with sarcopenia had poorer RFS and OS than those without sarcopenia. In contrast, patients with obesity had better OS than those without obesity.

Discussion

Body composition parameters, including SAT density and psoas muscle density, emerged as significant predictors of OS and RFS, respectively. Hence, our findings indicate that body composition is a helpful measurement to assess the oncological outcomes of patients with NMIBC.

Anthropometric characteristics and relationship with non-muscle invasive bladder cancer in Greece: A case-control study

BACKGROUND

Risk factors like smoking, radiation, chronic infections and exposure to occupational chemicals are strongly associated with occurrence of bladder cancer. Association between increased body weight and bladder cancer has been controversial. The aim of this case-control study is to evaluate association of anthropometric characteristics on bladder cancer incidence in Greek population.

METHODS

This case-control study was conducted at a tertiary hospital in Greece with cases being patients with bladder cancer diagnosed within the last 2 years and controls patients admitted to hospital for reason other than cancer and not related to common risk factors related to bladder cancer. Anthropometric characteristics like weight, height, body mass index, waist and hip circumference were measured. Analyses was done with R (Vienna, Austria).

RESULTS

Comparison between groups showed that patients with bladder cancer had higher weight, BMI and waist circumference compared to controls. However, multivariate, binomial logistic regression showed that only age (OR 1.03, 95% CI: 1-1.05, p = 0.02), no use of smoke (OR 0.12, 95% CI: 0.07-0.23, p < 0.001) and occupation related to bladder cancer (OR 7.45, 95% CI: 2.53-27.93, p < 0.001) significantly predicted the incidence of bladder cancer.

CONCLUSIONS

Bladder cancer incidence is strongly linked with specific risk factors such as smoking, occupation with exposure to chemicals and smoke, increasing age, radiation and chronic infections. Several studies have shown a weak association between anthropometric characteristics and bladder cancer, although most studies in European populations did not confirm these findings. Similarly in our case-control study in a Greek population, we found potential relationship between increased weight/BMI and waist circumference with bladder cancer, but the association disappeared in multivariate analysis.

Disparities in cause-specific mortality by race and sex among bladder cancer patients from the SEER database

PURPOSE

Previous literature shows that more bladder cancer patients overall die from causes other than the primary malignancy. Given known disparities in bladder cancer outcomes by race and sex, we aimed to characterize differences in cause-specific mortality for bladder cancer patients by these demographics.

METHODS

We identified 215,252 bladder cancer patients diagnosed with bladder cancer from 2000 to 2017 in the SEER 18 database. We calculated cumulative incidence of death from seven causes (bladder cancer, COPD, diabetes, heart disease, external, other cancer, other) to assess differences in cause-specific mortality between race and sex subgroups. We used multivariable Cox proportional hazards regression and Fine-Gray competing risk models to compare risk of bladder cancer-specific mortality between race and sex subgroups overall and stratified by cancer stage.

RESULTS

17% of patients died from bladder cancer (n = 36,923), 30% died from other causes (n = 65,076), and 53% were alive (n = 113,253). Among those who died, the most common cause of death was bladder cancer, followed by other cancer and diseases of the heart. All race-sex subgroups were more likely than white men to die from bladder cancer. Compared to white men, white women (HR: 1.20, 95% CI: 1.17-1.23) and Black women (HR: 1.57, 95% CI: 1.49-1.66) had a higher risk of dying from bladder cancer, overall and stratified by stage.

CONCLUSION

Among bladder cancer patients, death from other causes especially other cancer and heart disease contributed a large proportion of mortality. We found differences in cause-specific mortality by race-sex subgroups, with Black women having a particularly high risk of dying from bladder cancer.

Obesity and main urologic cancers: Current systematic evidence, novel biological mechanisms, perspectives and challenges

Urologic cancers (UC) account for 13.1% of all new cancer cases and 7.9% of all cancer-related deaths. A growing body of evidence has indicated a potential causal link between obesity and UC. The aim of the present review is to appraise in a critical and integrative manner evidence from meta-analyses and mechanistic studies on the role of obesity in four prevalent UC (kidney-KC, prostate-PC, urinary bladder-UBC, and testicular cancer-TC). Special emphasis is given on Mendelian Randomization Studies (MRS) corroborating a genetic causal association between obesity and UC, as well as on the role of classical and novel adipocytokines. Furthermore, the molecular pathways that link obesity to the development and progression of these cancers are reviewed. Available evidence indicates that obesity confers increased risk for KC, UBC, and advanced PC (20-82%, 10-19%, and 6-14%, respectively), whereas for TC adult height (5-cm increase) may increase the risk by 13%. Obese females tend to be more susceptible to UBC and KC than obese males. MRS have shown that a higher genetic-predicted BMI may be causally linked to KC and UBC but not PC and TC. Biological mechanisms that are involved in the association between excess body weight and UC include the Insulin-like Growth Factor axis, altered availability of sex hormones, chronic inflammation and oxidative stress, abnormal secretion of adipocytokines, ectopic fat deposition, dysbiosis of the gastrointestinal and urinary tract microbiomes and circadian rhythm dysregulation. Anti-hyperglycemic and non-steroidal anti-inflammatory drugs, statins, and adipokine receptor agonists/antagonists show potential as adjuvant cancer therapies. Identifying obesity as a modifiable risk factor for UC may have significant public health implications, allowing clinicians to tailor individualized prevention strategies for patients with excess body weight.

Mendelian randomization investigation identified the causal relationship between body fat indexes and the risk of bladder cancer

Background

Observational studies have suggested that obesity is associated with the risk of bladder cancer (BCa). However, their causal relationship remains unclear. This study aimed to prove the causal relationship between obesity and the risk of BCa by using Mendelian randomization.

Methods

Single-nucleotide polymorphisms (SNPs) correlated with body fat indexes were screened from several genome-wide association studies (GWAS) with more than 300,000 individuals. Summary-level genetic data of BCa-related GWAS were obtained from a European cohort with a sample size of 218,792. An inverse-variance-weighted (IVW) method was used as the major MR analysis. The MR-Egger regression, IVW regression, leave-one-out test, and MR-Pleiotropy Residual Sum and Outlier methods were used to test the reliability and stability of MR results.

Results

Genetically predicted per 1-SD increase in body fat indexes (whole body fat mass, and the right leg, left leg, right arm, left arm, and trunk fat mass) were associated with increased BCa risk with values of 51.8%, 77.9%, 75.1%, 67.2%, 59.7%, and 36.6%, respectively. Sensitivity analyses suggested that the genetically determined risk effect of obesity on BCa was stable and reliable.

Conclusions

Our study provided powerful evidence to support the causal hypothesis that the genetically predicted high body fat mass was associated with a risk increase for BCa. The finding is a new idea for drawing up prevention strategies for BCa.

Association of metabolic syndrome and the risk of bladder cancer: A prospective cohort study

Background

Metabolic syndrome (MetS) and its components have been shown as risk factors for several solid cancers. However, current epidemiological evidence about the relevance of MetS and bladder cancer risk was limited.

Methods

We conducted a prospective cohort study of 476,986 participants with undiagnosed bladder cancer based on the UK Biobank. MetS was defined as the presence of at least three of the five selected indicators: hypertension, central obesity, raised triglyceride, reduced HDL-cholesterol, and raised fasting plasma glucose. Bladder cancer has been identified through contact with the British Cancer Registry (median follow-up time: 6.6 years). We assessed hazard ratio (HR) and 95% confidence interval (CI) through Cox proportional hazard regression after adjusting for demographic and lifestyle factors. Non-linear associations for individual MetS components were assessed by the restricted cubic spline method.

Results

During a follow-up of 3,112,566 person-years, 487 cases of bladder cancer were ascertained. MetS (HR = 1.32, 95% CI = 1.08-1.61), central obesity (HR = 1.39, 95% CI = 1.15-1.68), dyslipidemia for HDL cholesterol (HR = 1.31, 95% CI = 1.04-1.66), and hyperglycemia (HR = 1.44, 95% CI = 1.16-1.79) were associated with elevated risk of bladder cancer. Bladder cancer risk increased with the number of MetS components. In stratified analyses, MetS showed similar effects in bladder cancer independently with sex, age, cigarette and alcohol use, physical activity, and dietary factors. Higher waist circumference, BMI, fasting blood glucose, and glycosylated hemoglobin were independently associated with increased risk of bladder cancer, with no evidence against non-linearity.

Conclusion

MetS might be an independent risk factor for bladder cancer. Our findings highlighted the importance of individualized management of MetS components for preventing bladder cancer.

Increased risk of bladder cancer in young adult men with hyperlipidemia: A population-based cohort study

A high-cholesterol diet increases the risk of bladder cancer. The purpose of this nationwide longitudinal population-based retrospective cohort study is to investigate whether hyperlipidemia is a risk factor for bladder cancer.Data from Taiwan National Health Insurance Database were analyzed. The primary study end point was the occurrence of newly diagnosed bladder cancer. The relative risk of bladder cancer in a hyperlipidemia cohort was compared with that in an age- and gender-matched non-hyperlipidemia cohort by using the Cox proportional hazards regression model. Cox regression analyses were further adjusted by the propensity score.Our data revealed that the hyperlipidemia cohort (n = 33,555) had a significantly higher subsequent risk of bladder cancer than did the non-hyperlipidemia cohort (n = 33,555) (adjusted hazard ratio [HR] = 1.37, P = .005) after propensity score adjustment. Subgroup analyses revealed that men in the hyperlipidemia cohort had a significantly higher subsequent risk of bladder cancer than did those in the non-hyperlipidemia cohort (adjusted HR = 1.36, P = .040). However, the risk of bladder cancer was not significantly different between women in the hyperlipidemia cohort and those in the non-hyperlipidemia cohort. Subgroup analyses further revealed that the risk of bladder cancer was significantly higher in men aged 20 to 39 years in the hyperlipidemia cohort than in those in the non-hyperlipidemia cohort (adjusted HR = 5.45, P = .029).In conclusion, hyperlipidemia is a risk factor for bladder cancer in young adult men.

The Sirenic Links between Diabetes, Obesity, and Bladder Cancer

There is considerable evidence of a positive association between the incidence of type 2 diabetes mellitus (T2DM) and obesity with bladder cancer (BCa), with the link between T2DM and obesity having already been established. There also appear to be potential associations between Pleckstrin homology domain containing S1 (PLEKHS1) and the Insulin-like Growth Factor (IGF) axis. Seven literature searches were carried out to investigate the backgrounds of these potential links. PLEKHS1 is a candidate biomarker in BCa, with mutations that are easily detectable in urine and increased expression seemingly associated with worse disease states. PLEKHS1 has also been implicated as a potential mediator for the onset of T2DM in people with obesity. The substantial evidence of the involvement of IGF in BCa, the role of the IGF axis in obesity and T2DM, and the global prevalence of T2DM and obesity suggest there is scope for investigating the links between these components. Preliminary findings on the relationship between PLEKHS1 and the IGF axis signal possible associations with BCa progression. This indicates that PLEKHS1 plays a role in the pathogenesis of BCa that may be mediated by members of the IGF axis. Further detailed research is needed to establish the relationship between PLEKHS1 and the IGF axis in BCa and determine how these phenomena overlap with T2DM and obesity.

Epidemiological link between obesity, type 2 diabetes mellitus and cancer

There exists a complex interaction between obesity, type 2 diabetes mellitus (T2DM) and cancer, and an increase in the incidence of cancer is expected with the growing obesity-diabetes pandemic. The association of cancer with diabetes mellitus and obesity appears to be site-specific, the highest risk being for post-menopausal breast cancer, endometrial cancer, and colorectal cancer. Moreover, there is worsening of hyperglycaemia with the onset of cancer, evidencing a bi-directional link between cancer and diabetes mellitus and the need for monitoring for diabetes in cancer survivors. In this review, we look at the epidemiological evidence from observational studies and Mendelian randomization studies linking obesity, diabetes, and cancer, as well as the complex pathophysiological mechanisms involved, including insulin resistance with associated hyperinsulinaemia, the effect of chronic low-grade inflammation, and the effect of various adipokines that are associated with obesity and T2DM. Additionally, we describe the novel therapeutic strategies, based on their role on the discrete pathophysiological mechanisms involved in the tumourigenesis.

Is metabolic syndrome associated with high tumor grade and stage of bladder cancer: a systematic review and meta-analysis

BACKGROUND

The aim of our study was to elaborate the association between metabolic syndrome (MS) and the tumor stage and grade of bladder cancer (BC).

METHODS

A systematic review and pooled analysis on PubMed, the Cochrane Library, Embase, Web of Science, CNKI, WANFANG and VIP from databases inception to July 24, 2020 was conducted by two independent authors. Relative risk (RR) was used as pooled effect estimates. The data analysis was accomplished by STATA 14.2.

RESULTS

Three English and four Chinese articles were included in the final analysis. A pooled analysis of six studies showed that patients in MS group were at a 1.94-fold risk of high-stage BC when compared to their counterparts (RR: 1.94; 95% CI: 1.59-2.37), and the difference was statistically significant. For the components of MS, except for hypertension, patients with obesity (RR: 1.61; 95% CI: 1.33-1.95), hyperglycemia (RR: 2.20; 95% CI: 1.49-3.26) and low high-density lipoprotein cholesterol (HDL) (RR: 1.98; 95% CI: 1.51-2.58) had significantly higher risks of high-stage BC than the control groups. A pooled analysis of six studies indicated that MS can contribute substantially to the vulnerability of high-grade BC with significant difference (RR: 1.50; 95% CI: 1.37-1.65). Furthermore, patients with obesity (RR: 1.41; 95% CI: 1.18-1.69), hyperglycemia (RR: 1.42; 95% CI: 1.30-1.56), hypertension (RR: 1.13; 95% CI: 1.03-1.24), low HDL (RR: 1.29; 95% CI: 1.14-1.46) and high triglyceride (TG) (RR: 1.28; 95% CI: 1.11-1.46) were at a higher risk of high-grade BC than their counterparts.

CONCLUSIONS

This meta-analysis revealed that MS and its components might be associated with high BC stage and grade.

The Epidemiology of Bladder Cancer

There are many risk factors for bladder cancer. During an initial assessment of a patient with bladder cancer, a careful discussion and history assessment is important. Particular focus should include social history with details regarding occupational background and discussion of any environmental exposure history.

Associating the risk of three urinary cancers with obesity and overweight: an overview with evidence mapping of systematic reviews

BACKGROUND

The relationship between cancer with overweight and obesity has been extensively reported. However, the association between urinary cancers with these risk factors remains unclear, with existing reports showing conflicting findings. The current review, therefore, sought to clarify the latter association by assessing the methodological and reporting quality of existing systematic reviews on the subject.

METHODS

We first screened PubMed, EMBASE, and Cochrane Library databases for relevant literature and subjected the resulting articles to meta-analysis. We adopted the AMSTAR-2 and PRISMA checklists for assessing methodological and reporting quality, respectively, then performed meta-analyses to determine the relationship between incidence and mortality of three types of urinary cancers with obesity and overweight. Indirect comparisons were also done across subgroups.

RESULTS

All systematic reviews (SRs) were of critically low methodological quality. Seventeen SRs had minimal reporting flaws, and 11 SRs had minor reporting flaws. We found an association between obesity with an incidence of kidney (RR = 1.68, 95% CI 1.47-1.92), bladder (RR = 1.1, 95% CI 1.07-1.13), and prostate (RR = 1.02, 95% CI 0.91, 1.13) cancers. Similarly, overweight was associated with the incidence of the three types of cancer, recording RR values of 1.37 (95% CI 1.26-1.48), 1.07 (95% CI 1.03-1.1), and 1 (95% CI 0.93, 1.07) for kidney, bladder, and prostate cancers, respectively. With regard to the dose analysis, the RR of BMI (per 5 kg/m2 increase) was associated with kidney (RR = 1.24, 95% CI 1.2-1.28), bladder (RR = 1.03, 95% CI 1.02-1.05), and prostate (RR = 1.02, 95% CI 1.01, 1.03) cancers.

CONCLUSIONS

This comprehensive quantitative analysis provides an affirmation that overweight and obesity are strong risk factors for kidney cancer, owing to a strong association between them. Conversely, a weak association between overweight and obesity with bladder and prostate cancers confirms their status as mild risk factors for the 2 types of cancer. But due to the low quality of included SRs, the results need to be interpreted with caution.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019119459.

Alterations of Lipid Metabolism in Cancer: Implications in Prognosis and Treatment

Cancer remains the second leading cause of mortality worldwide. In the course of this multistage and multifactorial disease, a set of alterations takes place, with genetic and environmental factors modulating tumorigenesis and disease progression. Metabolic alterations of tumors are well-recognized and are considered as one of the hallmarks of cancer. Cancer cells adapt their metabolic competences in order to efficiently supply their novel demands of energy to sustain cell proliferation and metastasis. At present, there is a growing interest in understanding the metabolic switch that occurs during tumorigenesis. Together with the Warburg effect and the increased glutaminolysis, lipid metabolism has emerged as essential for tumor development and progression. Indeed, several investigations have demonstrated the consequences of lipid metabolism alterations in cell migration, invasion, and angiogenesis, three basic steps occurring during metastasis. In addition, obesity and associated metabolic alterations have been shown to augment the risk of cancer and to worsen its prognosis. Consequently, an extensive collection of tumorigenic steps has been shown to be modulated by lipid metabolism, not only affecting the growth of primary tumors, but also mediating progression and metastasis. Besides, key enzymes involved in lipid-metabolic pathways have been associated with cancer survival and have been proposed as prognosis biomarkers of cancer. In this review, we will analyze the impact of obesity and related tumor microenviroment alterations as modifiable risk factors in cancer, focusing on the lipid alterations co-occurring during tumorigenesis. The value of precision technologies and its application to target lipid metabolism in cancer will also be discussed. The degree to which lipid alterations, together with current therapies and intake of specific dietary components, affect risk of cancer is now under investigation, and innovative therapeutic or preventive applications must be explored.

Carbohydrates, Glycemic Index, and Glycemic Load in Relation to Bladder Cancer Risk

Objective: Epidemiologic studies investigating the association between dietary carbohydrates as well as glycemic index and glycemic load (markers of carbohydrate quality) and bladder cancer risk have yielded inconsistent results. The aim of the present meta-analysis is to summarize the evidence on this association. Materials and Methods: A comprehensive literature search of articles published by December 2019 was performed in PubMed, Scopus, and Web of Science databases. A random-effects model was used to calculate the pooled odds ratios (ORs) and their corresponding 95% confidence intervals (CIs). Results: Twelve observational studies were included in the final analysis. There was no evidence of an association between consumption of carbohydrates and bladder cancer risk (pooled OR, 1.04; 95% CI, 0.92-1.17). No statistically significant association between glycemic load and bladder cancer was likewise found (pooled OR, 1.10; 95% CI, 0.85-1.42). However, there was a significant positive association between glycemic index and bladder cancer risk (pooled OR, 1.25; 95% CI, 1.11-1.41). In the dose-response analysis, the pooled OR (95% CI) per 10 units of glycemic index per day was 1.02 (95% CI, 1.01-1.04). Conclusion: In this meta-analysis, glycemic index showed a positive linear association with bladder cancer risk.

Dairy Product Consumption and Bladder Cancer Risk in the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cohort

Evidence has suggested that dairy product consumption lowers the risk of several cancers, but these benefits may not occur with bladder cancer. In a cohort of 101,721 subjects in the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial, we analyzed the effects of dairy product intake on bladder cancer risk using Cox proportional hazards regression. After a median of 12.5 years of follow-up, 776 new cases of bladder cancer were identified. We found no statistically significant association between total milk intake and bladder cancer risk. The multivariate-adjusted hazard ratio (HR) of bladder cancer for participants in the highest category of total milk intake compared with those in the lowest category was 1.13 (95% CI: 0.92–1.40; p for trend = 0.436). Among individual dairy foods, no statistically significant association was observed for a broad range of dairy products, including whole milk, 2% milk, 1% milk, skim milk, yogurt, regular butter, low fat butter, regular cheese, low fat cheese, and no fat cheese. These associations were not modified by smoking status (p for interaction > 0.05). In conclusion, findings from this large prospective analysis do not support an inverse association between dairy product consumption and bladder cancer risk.

Dietary fiber intake and the risk of bladder cancer in the Prostate, Lung, Colorectal and Ovarian (PLCO) cohort

Dietary fiber intake has been implicated as a protective factor for several human cancers in multiple epidemiologic studies. However, little is known about the effect of fiber intake on bladder cancer. This study examines the association between dietary fiber intake and bladder cancer risk among participants in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. A total of 101 721 participants were included in this study as they completed both the baseline questionnaire and the diet history questionnaire (cancer free before completion of the diet history questionnaire). Hazard ratios (HRs) and the corresponding 95% confidence intervals (CIs) were estimated using the Cox proportional hazards regression model. After a median of 12.5 years of follow-up, 776 new cases of bladder cancer were identified. Higher intake of total fiber, insoluble fiber and soluble fiber were not significantly associated with a reduced risk of bladder cancer. The multi-adjusted HRs (95 CIs) of highest versus lowest tertile of intake were 0.83 (0.66-1.04) for total fiber (P for trend = 0.098), 0.83 (95% CI: 0.67-1.03) for insoluble fiber (P for trend = 0.092) and 0.86 (95% CI: 0.68-1.08) for soluble fiber (P for trend = 0.168), respectively. There was no significant interaction of potential confounders, including education, body mass index and smoking status, with total fiber intake on bladder cancer risk. In summary, the findings of this prospective study show that there is no obvious evidence for a link between dietary fiber consumption and bladder cancer risk. Further large cohort studies are warranted to confirm these findings.

Impact of body size and body composition on bladder cancer outcomes: Risk stratification and opportunity for novel interventions

Body size is emerging as a novel and clinically-relevant patient factor in bladder cancer research. Historically, a patient's body mass index (BMI) has been used as a proxy for obesity but it shows inconsistent associations with risk of developing the disease as well as with most clinical outcomes. More specific body composition features can be derived for patients using a variety of methods. To date, skeletal muscle measurements derived from preoperative computed tomography scans have shown the most consistent associations with clinical outcomes. Importantly, skeletal muscle can potentially be modified through resistance training and/or nutritional interventions. Large scale studies that evaluate the prognostic impact of not only body composition features at baseline but also describe changes in body composition post-treatment are needed to move the field forward to ultimately improve clinical outcomes for bladder cancer patients.

Lifestyle associated factors and risk of urinary bladder cancer: A prospective cohort study from Norway

A number of lifestyle associated factors, such as high body mass index (BMI), low physical activity, and related metabolic disorders, are associated with increased risk of cancer at several sites. For urinary bladder cancer (BC), such studies show inconsistent results, which could result from inadequate adjustment for smoking and occupational exposure. In the population‐based Janus Cohort (n = 292 851), we investigated the independent and combined impact of BMI, physical activity, blood pressure, and blood lipids on the risk of BC, by thorough adjustment for smoking and potential occupational exposure. We used cox proportional hazard regression to estimate hazard ratios (HRs) with 95% confidence intervals (CIs) for the associations between the lifestyle associated factors and BC risk. The associations observed were dependent on smoking status and gender. Among men, diastolic blood pressure (DBP) (HR 1.07, 95% CI 1.02‐1.12) and systolic blood pressure (SBP) (HR 1.04, 95% CI 1.01‐1.07) were positively associated with BC risk. Stratification by smoking status revealed a positive association between DBP and BC risk in never smokers (HR 1.14, 95% CI 1.00‐1.30), while no association was seen for current and former smokers. A risk score, integrating information across the lifestyle factors was positively associated with BC risk in men (p_trend = 0.043). In women, physical activity was associated with a decreased BC risk, but only among never smokers (HR 0.65, 95% CI 0.45‐0.94). In conclusion, relations between lifestyle associated factors and BC risk were most evident in never smokers, suggesting that smoking dominates the relation in current smokers.

Bladder Cancer in Iran: An Epidemiological Review

PURPOSE

Bladder cancer is the sixth most common cancer in Iran. Information about the epidemiological situation of the disease and its risk factors is necessary for conducting a planning program to reduce the disease. This study is conducted with the aim of evaluating the epidemiological features of bladder cancer in Iran.

METHODS

This is a systematic review of the published articles in both Persian and English in international and national journals during the years 2000-2019 with key words of Iran and bladder cancer. Articles were selected from the national information database (SID, Magiran) and international databases (PubMed, Scopus, and Web of Science). Articles related to the epidemiological aspects of the disease, including incidence, prevalence, mortality, and risk factors, were evaluated.

RESULTS

The incidence rate of bladder cancer was about 1.6-115; cumulative survival rate was 0.95, mortality rate was 0.5-0.84 and its prevalence in the Iranian population was between 4.10% and 12.8%. The risk of developing malignancy in major risk factor groups, including smoking and opium, was 6.2 (2.04-18.7), increases in protein and animal fat consumption were about 5- and 19-times higher than in the general population, respectively. In terms of occupational exposure, bus and heavy truck drivers were 11.3 (1.3-92.05) more at risk than others.

CONCLUSION

Regarding the increasing trend of this disease, changes in lifestyle to reduce risk factors can be effective in decreasing the incidence and mortality rate of this malignancy.

The Correlation Between Bladder Cancer and Obesity, Overweight, Physical Inactivity, and Tobacco Use: An Ecological Study in Asian Countries

BACKGROUND

Bladder cancer is the ninth most common cancer in the world.

OBJECTIVES

This study aimed to determine the correlation between age-standardized incidence rates of bladder cancer and some risk factors in Asian countries through an extensive ecological analysis.

METHODS

This ecological study evaluated the correlation between age-standardized incidence rates of bladder cancer and obesity, overweight, physical inactivity, and tobacco use in 30 Asian countries. To determine the factors that were significantly related to age-standardized incidence rate of bladder cancer, a univariate analysis was performed using simple linear regression. In the next step, variables with p-values less than 0.25 were entered into a multivariate linear regression model.

RESULTS

The incidence of bladder cancer was higher in countries with higher prevalence of overweight (r2 = 0.36, p < 0.001), obesity (r2 = 0.34, p = 0.001), current daily tobacco use (r2 = 0.17, p = 0.03), and physical inactivity (r2 = 0.13, p = 0.04). The results of multiple regression analysis indicated a direct correlation between the incidence of bladder cancer and overweight (β = 0.15, p < 0.001) and current daily tobacco use (β = 0.21, p = 0.001).

CONCLUSIONS

There was a significant relationship between the incidence of bladder cancer and overweight and current daily tobacco use. Further epidemiological studies are needed to confirm this relationship.

Association of body mass index with bladder cancer risk in men depends on abdominal obesity

PURPOSE

The previous epidemiological studies about the associations between obesity and bladder cancer risk have reported inconsistent results. Therefore, we analyzed whether the abdominal obesity effected on the risk of developing bladder cancer according to body mass index (BMI) using nationally representative data from the National Health Insurance System (NHIS).

PATIENTS AND METHODS

Among people who underwent at least one health examination from 2009 to 2012 in Korea, 11,823,876 men without a previous diagnosis of bladder cancer were followed up until December 2015. Multiple Cox regression analysis was conducted to determine the hazard ratio (HR) and 95% confidence interval (CI) for the association between bladder cancer and BMI or waist circumference (WC).

RESULTS

Significant upward trends in the risk of bladder cancer were observed with increasing BMI or WC according to the multivariate-adjusted model. However, the association between BMI and bladder cancer is influenced by the presence of abdominal obesity. In the group with WC < 90 cm, there was no significant change in the HRs for bladder cancer development beyond the reference BMI. In contrast, the HRs for bladder cancer showed statistically significant increase as the BMI increased beyond the reference BMI in the group with WC ≥ 90 cm.

CONCLUSION

This population-based study showed that increasing BMI and increasing WC were risk factors for developing bladder cancer in men, independent of confounding variables. However, there was a discrepancy in the trend of bladder cancer development according to BMI between the groups with abdominal obesity and without abdominal obesity.

Body mass index modifies bladder cancer risk associated with low estrogen exposure among Egyptian women after menopause

PURPOSE

Investigators have reported inconsistent findings regarding associations between body mass index (BMI) and bladder cancer risk, and they have postulated that sex steroids mediate such associations. We assessed the impact of BMI on the relationship between bladder cancer risk and combinations of age at first childbirth, parity, and age at menopause, among Egyptian women.

METHODS

We used data from our multicenter case-control study of 419 cases and 786 controls in logistic regression models to estimate adjusted odds ratios (AORs) and 95% confidence intervals (CIs) of such associations.

RESULTS

Age > 18 years at first childbirth and parity ≤ 6 were significantly associated with bladder cancer risk, which was higher when both factors (AOR = 2.31, 95% CI = 1.55-3.43) and age at menopause < 45 years (AOR = 3.51, 95% CI = 1.88-6.55) were present. Early menopause was associated with higher bladder cancer risk in obese (AOR = 2.90, 95% CI = 1.40-5.98) but not normal weight women (AOR = 0.98, 95% CI = 0.58-1.65; P_interaction = 0.11), and the risk was greatest when both first childbirth at age > 18 years and parity ≤ 6 were present (AOR = 7.60, 95% CI = 1.84-31.35); however, overweight and obesity were associated with significantly lower bladder cancer risk (AOR = 0.59, 95% CI = 0.43-0.81, and AOR = 0.26, 95% CI = 0.18-0.38, respectively).

CONCLUSION

Body mass index appears to modify bladder cancer risk in Egyptian women after menopause by slightly enhancing the risk associated with low estrogen exposure among the obese only. Longitudinal studies of the BMI role in bladder malignancy in this distinctive population are required.

Prediagnosis obesity and secondary primary cancer risk in female cancer survivors: A national cohort study

BACKGROUND

This study evaluated the effects of body mass index (BMI) before the diagnosis of the first primary cancer on the development of secondary primary cancers (SPCs) in female cancer survivors.

METHODS

This study population included 146 377 Korean female cancer survivors whose first primary cancer was diagnosed between 2002 and 2010. The incidence of SPCs was evaluated throughout follow-up until December 2011. We used Cox proportional hazards models to calculate the hazard ratios of SPCs with prediagnosis BMI and compared it to those of first cancers in the general population.

RESULTS

After 565 877 person-years of follow-up, 2222 patients with SPC were observed. The higher BMI was more in female cancer survivors than in general population. The age-standardized incidence rate of cancer in cancer survivors was 2.02 times higher than that of the general population. There were positive linear trends between prediagnosis BMI and risk of overall, colorectal, ovary, thyroid, and obesity-related SPCs. In addition, the BMI-SPC risk association was statistically significant in female cancer survivors without smoking history (P_trend  = 0.001) and with a localized first primary cancer (P_trend  = 0.014). However, the magnitude of the BMI-SPC risk association was similar to that for first cancers in the general population (P_{heterogeneity}  = 0.403 in BMI ≥ 30.0 kg/m² ).

CONCLUSIONS

In female cancer survivors, prediagnosis obesity was a risk factor for overall, individual, and obesity-related SPCs. However, the magnitude of the BMI-SPC risk association was similar to that for first cancers in the general population.

The association between serum zinc level and overweight/obesity: a meta-analysis

PURPOSE

The association between serum zinc level and overweight/obesity remains controversial. Hence, we performed a meta-analysis to summarize the relationships.

METHODS

A systematic literature search was performed in PubMed, Web of Science and Embase for relevant English articles up to April 20, 2018. The pooled standardized mean difference (SMD) with 95% confidence interval (CI) was calculated with the random-effect model.

RESULTS

For children and adults, the results showed that serum zinc level was significantly lower in the cases compared to controls ([SMD (95% CI): - 1.13 (- 2.03, - 0.23), Z = 2.45, P for Z = 0.014; I² = 97.1%, P for I² < 0.001] and [SMD (95% CI): - 0.41 (- 0.68, - 0.15), Z = 3.03, P for Z = 0.002; I² = 62.9%, P for I² = 0.009], respectively). The difference of serum zinc level between overweight adults and controls was not statistically significant [SMD (95% CI): - 0.09 (- 0.27, 0.09), Z = 0.97, P for Z = 0.334; I² = 0.0%, P for I² = 0.411]. In subgroup analyses, a lower serum zinc level in obese children compared with non-obese controls was observed [SMD (95% CI): - 2.14 (- 3.20, - 1.09)], and the SMD differ significantly between obese adults and controls in the case-control studies [SMD (95% CI): - 0.49 (- 0.90, - 0.08)].

CONCLUSION

Our meta-analysis suggested that the serum zinc level was significantly lower in obese children and adults. More large observational studies are required to confirm these results in future research.

The association between metabolic syndrome and bladder cancer susceptibility and prognosis: an updated comprehensive evidence synthesis of 95 observational studies involving 97,795,299 subjects

Background

The association between metabolic syndrome (MS) and bladder cancer (BC) was not fully investigated, and most primary studies and pooled analyses were only focused on certain specific components.

Objective

To further investigate this issue and obtain more precise findings, we conducted this updated evidence synthesis of published studies, which involved not only MS components but also the MS in its entirety.

Materials and methods

We searched the PubMed, EMBASE, and Web of Science databases for observational studies on the association between BC susceptibility and/or mortality, and MS and its components. We extracted data from included studies, evaluated heterogeneity, and performed meta-analytic quantitative syntheses.

Results

A total of 95 studies with 97,795,299 subjects were included in the present study. According to the results, MS significantly increased the risk of BC (risk ratio [RR]=1.11, 95% CI=1.00–1.23); diabetes significantly increased the risk of BC (RR=1.29, 95% CI=1.19–1.39) and associated with poor survival (RR=1.24, 95% CI=1.08–1.43). Excessive body weight was associated with increased susceptibility (RR=1.07, 95% CI=1.02–1.12), recurrence (RR=1.46, 95% CI=1.18–1.81), and mortality (RR=1.17, 95% CI=1.00–1.37). As indicated by cumulative meta-analysis, sample size was inadequate for the association between BC susceptibility and MS, the association between BC recurrence and excessive body weight, and the association between BC survival and diabetes. The sample size of the meta-analysis was enough to reach a stable pooled effect for other associations.

Conclusion

Diabetes and excessive body weight as components of MS are associated with increased susceptibility and poor prognosis of BC. Uncertainty remains concerning the impact of overall MS, hypertension, and dyslipidemia on BC susceptibility and prognosis, for which further investigations are needed.

An increased body mass index is associated with a worse prognosis in patients administered BCG immunotherapy for T1 bladder cancer

PURPOSE

The body mass index (BMI) may be associated with an increased incidence and aggressiveness of urological cancers. In this study, we aimed to evaluate the impact of the BMI on survival in patients with T1G3 non-muscle-invasive bladder cancer (NMIBC).

METHODS

A total of 1155 T1G3 NMIBC patients from 13 academic institutions were retrospectively reviewed and patients administered adjuvant intravesical Bacillus Calmette-Guérin (BCG) immunotherapy with maintenance were included. Multivariable Cox regression analysis was performed to identify factors predictive of recurrence and progression.

RESULTS

After re-TURBT, 288 patients (27.53%) showed residual high-grade NMIBC, while 867 (82.89%) were negative. During follow-up, 678 (64.82%) suffered recurrence, and 303 (30%) progression, 150 (14.34%) died of all causes, and 77 (7.36%) died of bladder cancer. At multivariate analysis, tumor size (hazard ratio [HR]:1.3; p = 0.001), and multifocality (HR:1.24; p = 0.004) were significantly associated with recurrence (c-index for the model:55.98). Overweight (HR: 4; p < 0.001) and obesity (HR:5.33 p < 0.001) were significantly associated with an increased risk of recurrence. Addition of the BMI to a model that included standard clinicopathological factors increased the C-index by 9.9. For progression, we found that tumor size (HR:1.63; p < 0.001), multifocality (HR:1.31; p = 0.01) and concomitant CIS (HR: 2.07; p < 0.001) were significant prognostic factors at multivariate analysis (C-index 63.8). Overweight (HR: 2.52; p < 0.001) and obesity (HR: 2.521 p < 0.001) were significantly associated with an increased risk of progression. Addition of the BMI to a model that included standard clinicopathological factors increased the C-index by 1.9.

CONCLUSIONS

The BMI could have a relevant role in the clinical management of T1G3 NMIBC, if associated with bladder cancer recurrence and progression. In particular, this anthropometric factor should be taken into account at initial diagnosis and in therapeutic strategy decision making.

Vitamin D, obesity and leptin in relation to bladder cancer incidence and survival: prospective protocol study

INTRODUCTION

Bladder cancer (BC) (including renal pelvis, ureter and urethra) is one of the most common urogenital cancers and the fourth most frequent cancer in men in the USA. In Norway, the incidence of BC has increased over the last decades. The age-standardised incidence rates per 100 000 for 2011-2015 were 53.7 in men and 16.5 in women. Compared to the 5-year period 2006-2010, the percentage increase in incidence was 6.1% in men and 12.3% in women. The recurrence rate of BC is over 50%, the highest recurrence rate of any malignancy. Smoking and occupational exposure to aromatic amines are recognised as the major risk factors. Recently, low-serum level of 25-hydroxy vitamin D (25(OH)D) and obesity have been suggested to increase the BC risk, and leptin, which is important in weight regulation, may be involved in bladder carcinogenesis. More knowledge on potential risk factors for BC is necessary for planning and implementing primary prevention measures.

METHODS AND ANALYSES

Cohort and nested case-control studies will be carried out using the population-based Janus Serum Bank Cohort consisting of prediagnostic sera, clinical measurement data (body height and weight, body surface area and weight change over time, blood pressure, cholesterol and triglycerides) and self-reported information on lifestyle factors (smoking, physical activity). Participants were followed from cohort inclusion (1972-2003) through 2014. The cohort will be linked to the Cancer Registry of Norway (cancer data), the National Cause of Death Registry (date and cause of death), National Population Registry (vital status) and Statistic Norway (education and occupation). Serum samples will be analysed for 25(OH)D, vitamin D binding protein, leptin, albumin, calcium and parathyroid hormone. Cox regression and conditional logistic regression models and mediation analysis will be used to estimate association between the exposures and BC.

ETHICS AND DISSEMINATION

The study has been approved by the Regional Committee for Medical Research Ethics and is funded by the Norwegian Cancer Society. Results will be published in peer-reviewed journals, at scientific conferences and through press releases.

Review of refractory ceramic fiber (RCF) toxicity, epidemiology and occupational exposure

This literature review on refractory ceramic fibers (RCF) summarizes relevant information on manufacturing, processing, applications, occupational exposure, toxicology and epidemiology studies. Rodent toxicology studies conducted in the 1980s showed that RCF caused fibrosis, lung cancer and mesothelioma. Interpretation of these studies was difficult for various reasons (e.g. overload in chronic inhalation bioassays), but spurred the development of a comprehensive product stewardship program under EPA and later OSHA oversight. Epidemiology studies (both morbidity and mortality) were undertaken to learn more about possible health effects resulting from occupational exposure. No chronic animal bioassay studies on RCF have been conducted since the 1980s. The results of the ongoing epidemiology studies confirm that occupational exposure to RCF is associated with the development of pleural plaques and minor decrements in lung function, but no interstitial fibrosis or incremental lung cancer. Evidence supporting a finding that urinary tumors are associated with RCF exposure remains, but is weaker. One reported, but unconfirmed, mesothelioma was found in an individual with prior occupational asbestos exposure. An elevated SMR for leukemia was found, but was absent in the highly exposed group and has not been observed in studies of other mineral fibers. The industry will continue the product stewardship program including the mortality study.

Association of body mass index with bladder cancer risk: a dose-response meta-analysis of prospective cohort studies

Prospective epidemiologic studies on the association between body mass index (BMI) and bladder cancer yielded inconsistent findings. This study sought to quantitatively summarize the evidence by performing a dose-response meta-analysis on prospective cohort studies. Eligible studies were retrieved via PubMed and Embase databases, and by manual review of the references. Linear and nonlinear trend analyses were conducted to explore the relationships between BMI and bladder cancer risk. Meta-analyses on the categories of overweight and obesity were also conducted. The summary relative risk (SRR) was estimated. Heterogeneity across the studies was explored through subgroup analyses based on gender, age, year of publication, sample size, assessment of BMI, geographic location, physical activity and family history of cancer. A total of 14 prospective cohort studies involving 12,642 cases were included. Result of the dose-response analysis showed a nonlinear positive relationship between BMI and bladder cancer (SRR = 1.03, 95% CI: 1.01-1.06, P-nonlinearity =0.031), suggesting that per 5 kg/m2 increment on BMI corresponded to a 3.1 % increase of bladder cancer risk, especially BMI exceed 30kg/m2.Furthermore, significant positive association was also observed between obesity category and bladder cancer risk (SRR: 1.10, 95%CI: 1.03-1.17). In summary, this dose-response meta-analysis suggests a nonlinear positive association between BMI and bladder cancer risk. Further studies are required to confirm these findings and elucidate the pathogenic mechanisms.

Estimating the impact of body mass index on bladder cancer risk: Stratification by smoking status

We estimated the impact of obesity on bladder cancer with stratification by smoking status using nationally representative data on the Korean population from the National Health Insurance System (NHIS). Of the 45,850,458 people who underwent at last one health examination from 2009 to 2012, 23,378,895 without bladder cancer were followed from the January 2009 to the December 2015. First, the HR for bladder cancer was lowest in people with a BMI < 18.5 (HR = 0.92) and highest for those with BMI ≥ 30 (HR = 1.17) in multiple Cox regression analyses. The positive association between bladder cancer and BMI showed an increasing trend beyond the reference BMI. Second, an analysis of HR for bladder cancer stratified by obesity across smoking status strata showed a significant trend of increasing HR for bladder cancer across obesity and smoking status in multivariate-adjusted models. Conclusively, this population-based study showed that increasing BMI was a risk factor for bladder cancer independent of confounding variables. When stratified by smoking status, there was still a positive association between bladder cancer and BMI (P for trend < 0.01).

Precision Nutrition for Targeting Lipid Metabolism in Colorectal Cancer

Cancer is a multistage and multifactorial condition with genetic and environmental factors modulating tumorogenesis and disease progression. Nevertheless, cancer is preventable, as one third of cancer deaths could be avoided by modifying key risk factors. Nutrients can directly affect fundamental cellular processes and are considered among the most important risk factors in colorectal cancer (CRC). Red and processed meat, poultry consumption, fiber, and folate are the best-known diet components that interact with colorectal cancer susceptibility. In addition, the direct association of an unhealthy diet with obesity and dysbiosis opens new routes in the understanding of how daily diet nutrients could influence cancer prognosis. In the “omics” era, traditional nutrition has been naturally evolved to precision nutrition where technical developments have contributed to a more accurate discipline. In this sense, genomic and transcriptomic studies have been extensively used in precision nutrition approaches. However, the relation between CRC carcinogenesis and nutrition factors is more complex than originally expected. Together with classical diet-nutrition-related genes, nowadays, lipid-metabolism-related genes have acquired relevant interest in precision nutrition studies. Lipids regulate very diverse cellular processes from ATP synthesis and the activation of essential cell-signaling pathways to membrane organization and plasticity. Therefore, a wide range of tumorogenic steps can be influenced by lipid metabolism, both in primary tumours and distal metastasis. The extent to which genetic variants, together with the intake of specific dietary components, affect the risk of CRC is currently under investigation, and new therapeutic or preventive applications must be explored in CRC models. In this review, we will go in depth into the study of co-occurring events, which orchestrate CRC tumorogenesis and are essential for the evolution of precision nutrition paradigms. Likewise, we will discuss the application of precision nutrition approaches to target lipid metabolism in CRC.

Association between Metabolic Syndrome and Recurrence of Nonmuscle Invasive Bladder Cancer following bacillus Calmette-Guérin Treatment

Introduction

Intravesical bacillus Calmette-Guérin (BCG) therapy is the gold standard adjuvant treatment for patients with high-grade non-muscle-invasive bladder cancer (NMIBC). Despite the association between metabolic syndrome (MetS) and bladder cancer, the association between MetS and BCG failure is unknown. The objective of this study was to characterize disease recurrence following BCG in patients with and without MetS.

Methods

We retrospectively evaluated the records of patients undergoing TURBT at our institution in 2012-2015 for NMIBC and identified those who received adjuvant BCG therapy. MetS was defined as having three of four components: diabetes mellitus, hyperlipidemia, hypertension, or body mass index (BMI)≥30kg/m². The primary outcome was recurrence or progression. Descriptive statistics, chi-squared analysis, Kaplan-Meier survival analysis, and Cox multivariable regression analyses were performed.

Results

High grade was present in 83/90 (92.2%) patients. MetS was present in 27/90 (30%) patients. Median follow-up was 20 months. On Kaplan-Meier analysis, patients with MetS had worse DFS compared with patient without MetS. On multivariable analysis, BMI≥30 kg/m² was a significant predictor of recurrence or progression (HR 2.94, 95% CI: 1.43-6.03). Presence of MetS did not significantly affect the type of BCG failure.

Conclusions

The association between MetS and failure to respond to BCG therapy is multifactorial but is in part associated with obesity. Elevated BMI is strongly associated with recurrence or progression. Further studies are warranted to investigate the relationship between increased adiposity and response to BCG, especially as other novel immunotherapeutic agents are likely to enter the NMIBC space.

Risk of second primary cancer associated with pre-diagnostic smoking, alcohol, and obesity in women with keratinocyte carcinoma

Keratinocyte carcinoma (KC), which includes basal-cell carcinoma (BCC) and squamous-cell cancer (SCC), has been associated with an increased risk of second primary cancers (SPCs), although the reason for this increase is unknown. We assessed the effects of smoking, alcohol, and obesity prior to the diagnosis of KC on the development of SPCs, as these are well-established risk factors for multiple cancers and may also contribute to the increased risk of SPCs among those with KC. A total of 15,628 women with self-reported KC were identified in the Nurses' Health Study. Incident SPCs were assessed throughout the follow-up until June 2012. Cox proportional hazards models were used to calculate the hazard ratios (HRs) of SPC associated with pre-diagnostic smoking, alcohol and body mass index (BMI). We also compared these risk estimates to those for first cancers in all cohort participants. During 193,695 person-years of follow-up, we recorded 2839 SPC cases. Compared with never smokers, current smokers had a significantly elevated risk for SPC overall and specifically for lung, colorectal, and bladder cancers. We also found a positive association between higher BMI and risk for SPC overall as well as for endometrial and bladder SPCs. Women with KC who consumed alcohol ≥30g/day had a marginally higher risk of SPC compared to non-drinkers. The associations between incident SPC risk among KC cases and smoking, alcohol, and obesity appeared similar to the associations between these risk factors and the incident first primary cancers in the whole cohort. Only in the heavy smoking (≥25 cigarettes/day) category was the HR for SPC after KC (2.34; 95% CI 1.98-2.76) slightly higher than that for the first cancer in the overall cohort (HR 1.86; 95% CI 1.75-1.98, P_{heterogeneity}=0.01). In conclusion, pre-diagnostic smoking, alcohol and obesity prior to KC diagnosis were associated with risk of SPCs.

Epidemiological bases and molecular mechanisms linking obesity, diabetes, and cancer

The association between diabetes and cancer was hypothesized almost one century ago. Today, a vast number of epidemiological studies support that obese and diabetic populations are more likely to experience tissue-specific cancers, but the underlying molecular mechanisms remain unknown. Obesity, diabetes, and cancer share many hormonal, immune, and metabolic changes that may account for the relationship between diabetes and cancer. In addition, antidiabetic treatments may have an impact on the occurrence and course of some cancers. Moreover, some anticancer treatments may induce diabetes. These observations aroused a great controversy because of the ethical implications and the associated commercial interests. We report an epidemiological update from a mechanistic perspective that suggests the existence of many common and differential individual mechanisms linking obesity and type 1 and 2 diabetes mellitus to certain cancers. The challenge today is to identify the molecular links responsible for this association. Classification of cancers by their molecular signatures may facilitate future mechanistic and epidemiological studies.

Exercise Decreases and Smoking Increases Bladder Cancer Mortality

BACKGROUND

The aim of this study was to investigate modifiable lifestyle factors of smoking, exercise, and obesity with bladder cancer mortality.

PATIENTS AND METHODS

We used mortality-linked data from the National Health Information Survey from 1998 through 2006. The primary outcome was bladder cancer-specific mortality. The primary exposures were self-reported smoking status (never- vs. former vs. current smoker), self-reported exercise (dichotomized as "did no exercise" vs. "light, moderate, or vigorous exercise in ≥ 10-minute bouts"), and body mass index. We utilized multivariable adjusted Cox proportional hazards regression models, with delayed entry to account for age at survey interview.

RESULTS

Complete data were available on 222,163 participants, of whom 96,715 (44%) were men and 146,014 (66%) were non-Hispanic whites, and among whom we identified 83 bladder cancer-specific deaths. In multivariate analyses, individuals who reported any exercise were 47% less likely (adjusted hazard ratio [HR_adj], 0.53; 95% confidence interval [CI], 0.29-0.96; P = .038) to die of bladder cancer than "no exercise". Compared with never-smokers, current (HR_adj, 4.24; 95% CI, 1.89-9.65; P = .001) and former (HR_adj, 2.95; 95% CI, 1.50-5.79; P = .002) smokers were 4 and 3 times more likely, respectively, to die of bladder cancer. There were no significant associations of body mass index with bladder cancer mortality.

CONCLUSION

Exercise decreases and current smoking increases the risk of bladder cancer-specific mortality. These data suggest that exercise and smoking cessation interventions may reduce bladder cancer death.

Prediagnosis Body Mass Index and Risk of Secondary Primary Cancer in Male Cancer Survivors: A Large Cohort Study

Purpose Male cancer survivors have a higher risk of cancer than the general population, which might be caused by an increased prevalence of obesity or susceptibility to obesity-related carcinogenesis. We assessed the effects of obesity before the diagnosis of a first cancer on the development of secondary primary cancers (SPCs). Methods The study population consisted of 239,615 Korean male cancer survivors between January 2003 and December 2010. Incident SPCs were assessed throughout follow-up until December 2011. Cox proportional hazards models were used to calculate the hazard ratios of SPCs associated with prediagnosis body mass index (BMI), which were compared with those of first cancers in all cohort participants. Results After 1,614,583 person-years of follow-up, we observed 4,799 patients with SPC. The age-standardized incidence rate of cancer in cancer survivors was 1.1 times higher than that of the general population. We found positive linear trends between prediagnosis BMI and risk of all-combined, colorectal, liver, lymphoma, biliary tract, kidney, and obesity-related SPCs. The magnitude of the BMI-SPC risk association in male cancer survivors was stronger than that for first cancers in the general population, whereas the mean BMI was similar in both groups. In the severely obese category (BMI ≥ 30 kg/m2), the adjusted hazard ratios for SPCs among cancer survivors (1.41; 95% CI, 1.15 to 1.74) were significantly higher than those for first cancers among all cohort participants (1.12; 95% CI, 1.09 to 1.16; Pheterogeneity < .01). Conclusion Prediagnosis obesity is a risk factor for overall and individual SPCs, and the strength of the BMI-cancer association is slightly stronger in male cancer survivors than in the general population.

Molecular targets in urothelial cancer: detection, treatment, and animal models of bladder cancer

Bladder cancer remains one of the most expensive cancers to treat in the United States due to the length of required treatment and degree of recurrence. In order to treat bladder cancer more effectively, targeted therapies are being investigated. In order to use targeted therapy in a patient, it is important to provide a genetic background of the patient. Recent advances in genome sequencing, as well as transcriptome analysis, have identified major pathway components altered in bladder cancer. The purpose of this review is to provide a broad background on bladder cancer, including its causes, diagnosis, stages, treatments, animal models, as well as signaling pathways in bladder cancer. The major focus is given to the PI3K/AKT pathway, p53/pRb signaling pathways, and the histone modification machinery. Because several promising immunological therapies are also emerging in the treatment of bladder cancer, focus is also given on general activation of the immune system for the treatment of bladder cancer.

Modifiable risk factors for the prevention of bladder cancer: a systematic review of meta-analyses

Each year, 430,000 people are diagnosed with bladder cancer. Due to the high recurrence rate of the disease, primary prevention is paramount. Therefore, we reviewed all meta-analyses on modifiable risk factors of primary bladder cancer. PubMed, Embase and Cochrane database were systematically searched for meta-analyses on modifiable risk factors published between 1995 and 2015. When appropriate, meta-analyses (MA) were combined in meta-meta-analysis (MMA). If not, the most comprehensive MA was selected based on the number of primary studies included. Probability of causation was calculated for individual factors and a subset of lifestyle factors combined. Of 1496 articles identified, 5 were combined in MMA and 21 were most comprehensive on a single risk factor. Statistically significant associations were found for current (RR 3.14) or former (RR 1.83) cigarette smoking, pipe (RR 1.9) or cigar (RR 2.3) smoking, antioxidant supplementation (RR 1.52), obesity (RR 1.10), higher physical activity levels (RR 0.86), higher body levels of selenium (RR 0.61) and vitamin D (RR 0.75), and higher intakes of: processed meat (RR 1.22), vitamin A (RR 0.82), vitamin E (RR 0.82), folate (RR 0.84), fruit (RR 0.77), vegetables (RR 0.83), citrus fruit (RR 0.85), and cruciferous vegetables (RR 0.84). Finally, three occupations with the highest risk were tobacco workers (RR 1.72), dye workers (RR 1.58), and chimney sweeps (RR 1.53). The probability of causation for individual factors ranged from 4 to 68 %. The combined probability of causation was 81.8 %. Modification of lifestyle and occupational exposures can considerably reduce the bladder cancer burden. While smoking remains one of the key risk factors, also several diet-related and occupational factors are very relevant.

Obesity and Outcomes in Patients with Metastatic Urothelial Carcinoma

Background: Obesity has been associated with worse outcomes in patients with clinically localized urothelial cancer. However, this impact has not been evaluated in metastatic disease.

Objective: To assess the impact of obesity on outcomes of patients with metastatic urothelial cancer.

Methods: Data from 537 patients were aggregated from eight phase II and phase III clinical trials investigating first-line cisplatin-based combination therapy in metastatic urothelial cancer. Chemotherapy regimen, adverse events, treatment response, and survival outcomes were compared across body mass index (BMI) and body surface area (BSA) categories.

Results: BMI was classified according to WHO criteria (<18.5 underweight, 18.5–24.99 normal weight, 25–29.99 overweight, >30 obese). BSA was classified as either below or greater than or equal to (average for this cohort (1.87 m² for males and 1.66 m² for females). There was no significant difference in number of chemotherapy cycles, adverse events, and response rate or survival outcomes (overall and progression-free) across BMI and BSA categories. There was no significant difference in adverse events across BMI categories, but the incidences of embolic events and renal failure were higher in patients with an average or higher BSA than those with a lower than average BSA (6.6% vs. 3.1% for renal failure p = 0.06; 5.9% vs. 2.7% for renal failure, p = 0.07). There was no significant difference in response rate or survival outcomes (overall and progression-free) amongst BMI and BSA categories.

Conclusions: Obese patients with metastatic urothelial cancer on cisplatin-based therapies have similar response rates, survival outcomes, and tolerability of cisplatin-based therapy to non-obese patients.

The evaluation of the association between the metabolic syndrome and tumor grade and stage of bladder cancer in a Chinese population

Objective

The objective of this article was to summarize the relationship between some components of metabolic syndrome (MetS) and the histopathologic findings in bladder cancer in a Chinese population.

Methods

We retrospectively analyzed data of 323 patients from the Department of Urology, Second Hospital of Tianjin Medical University between January 2012 and January 2014. All the patients were diagnosed with bladder cancer for the first time. Age, height, weight, histologic stage, grade, the presence of hypertension, diabetes mellitus, and body mass index were evaluated. The 2009 American Joint Committee on Cancer TNM staging system was used, with Ta and T1 tumors accepted as lower stage and T2, T3, and T4 tumors as higher stage bladder cancers. Also, pathologists assigned tumor grade according to the 1973 World Health Organization grading system. Noninvasive papillary urothelial neoplasms of low malignant potential were regarded as low grade. Analyses were completed using chi-square tests and logistic regression analysis.

Results

Of the 323 patients, 164 had hypertension, 151 had diabetes mellitus, and 213 had a body mass index ≥25 kg/m². MetS was significantly associated with histologic grade (P<0.001) and stage (P=0.006) of bladder cancer. Adjusted for age in binary logistic regression analysis, the presence of MetS predicts the risk of higher T stage (odds ratio =4.029, P<0.001) and grade (odds ratio =3.870, P<0.001) of bladder cancer.

Conclusion

The patients with MetS in the People’s Republic of China were found to have statistically significant higher T stage and grade of bladder cancer.

Diabetes Pharmacotherapies and Bladder Cancer: A Medicare Epidemiologic Study

OBJECTIVE

Patients with type II diabetes have an increased risk of bladder cancer and are commonly treated with thiazolidinediones and angiotensin receptor blockers (ARBs), which have been linked to cancer risk. We explored the relationship between use of one or both of these medication types and incident bladder cancer among diabetic patients (diabetics) enrolled in Medicare.

RESEARCH DESIGN AND METHODS

We constructed both a prevalent and incident retrospective cohort of pharmacologically treated prevalent diabetics enrolled in a Medicare fee-for-service plan using inpatient, outpatient (2003-2011) and prescription (2006-2011) administrative data. The association of incident bladder cancer with exposure to pioglitazone, rosiglitazone and ARBs was studied using muitivariable Cox's hazard models with time-dependent covariates in each of the two cohorts.

RESULTS

We identified 1,161,443 prevalent and 320,090 incident pharmacologically treated diabetics, among whom 4433 and 1159, respectively, developed incident bladder cancers. In the prevalent cohort mean age was 75.1 years, mean follow-up time was 38.0 months, 20.2% filled a prescription for pioglitazone during follow-up, 10.4% received rosiglitazone, 31.6% received an ARB and 8.0% received combined therapy with pioglitazone + ARB. We found a positive association between bladder cancer and duration of pioglitazone use in the prevalent cohort (P for trend = 0.008), with ≥24 months of pioglitazone exposure corresponding to a 16% (95% confidence interval 0-35%) increase in the incidence of bladder cancer compared to no use. There was a positive association between bladder cancer and rosiglitazone use for <24 months in the prevalent cohort, but no association with ARB use. There were no significant associations in the incident cohort.

CONCLUSIONS

We found that the incidence of bladder cancer increased with duration of pioglitazone use in a prevalent cohort of diabetics aged 65+ years residing in the USA, but not an incident cohort.

Expression of aquaporin 1 in bladder uroepithelial cell carcinoma and its relevance to recurrence

OBJECTIVES

To explore the expression of aquaporin 1 (AQP1) in bladder uroepithelium cell carcinoma (BUCC) and its relevance to recurrence.

MATERIALS AND METHODS

Tissue samples from 45 BUCC patients who underwent total cystectomy or transurethral resection of bladder tumor (TURBT) and from 40 patients with non-bladder cancers who underwent special detection or treatments were collected. The level of expression of AQP1 in BUCC tissues and normal bladder tissues was assessed by immunohistochemistry so as to analyze the relevance to pathological patterns and time of recurrence in BUCC patients.

RESULTS

The expression levels of AQP1 normal bladder tissues and BUCC tissues were 2.175±0.693 and 3.689±0.701, respectively, and the difference was significant (t=9.99, P<0.0001). Marked increase was noted with BUCC histological grade and pathological stage (P<0.01). Moreover, the expression of AQP1 was evidently higher in cancerous tissues with lymph node metastasis than in those without (P<0.01). With short-term recurrence, the positive cell expression rate of AQP1 was higher in primary tissues, which increased obviously after recurrence. Additionally, the recurrent time of BUCC was negatively associated with the positive cell expression rate of AQP1 and the difference between the expression of AQP1 before and after recurrence (r=-0.843, F=39.302, P=0.000; r=-0.829, F=35.191, P=0.000).

CONCLUSIONS

AQP1, which reflects the grade, stage, lymph node metastasis and recurrence of BUCC, has potential guiding significance in the diagnosis and treatment of bladder cancarcinoma.

Metabolic syndrome and the risk of urothelial carcinoma of the bladder: a case-control study

BACKGROUND

The Metabolic syndrome (MetS) is an emerging condition worldwide, consistently associated with an increased risk of several cancers. Some information exists on urothelial carcinoma of the bladder (UCB) and MetS. This study aims at further evaluating the association between the MetS and UCB.

METHODS

Between 2003 and 2014 in Italy, we conducted a hospital-based case-control study, enrolling 690 incident UCB patients and 665 cancer-free matched patients. The MetS was defined as the presence of at least three of the four selected indicators: abdominal obesity, hypercholesterolemia, hypertension, and diabetes. Odds ratios (ORs) and corresponding 95 % confidence intervals (CIs) for MetS and its components were estimated through multiple logistic regression models, adjusting for potential confounders.

RESULTS

Patients with MetS were at a 2-fold higher risk of UCB (95 % CI:1.38-3.19), compared to those without the MetS. In particular, ORs for bladder cancer were 2.20 (95 % CI:1.42-3.38) for diabetes, 0.88 (95 % CI: 0.66-1.17) for hypertension, 1.16 (95 % CI: 0.80-1.67) for hypercholesterolemia, and 1.63 (95 % CI:1.22-2.19) for abdominal obesity. No heterogeneity in risks emerged across strata of sex, age, education, geographical area, and smoking habits. Overall, 8.1 % (95 % CI: 3.9-12.4 %) of UCB cases were attributable to the MetS.

CONCLUSIONS

This study supports a positive association between the MetS and bladder cancer risk.