Dietary factors in cancer of the lower urinary tract

The Association between Tea Consumption and Bladder Cancer Risk Based on the Bladder Cancer Epidemiology and Nutritional Determinants (BLEND) International Consortium

OBJECTIVES

Evidence regarding the association between tea consumption and bladder cancer (BC) risk is inconsistent. This study aimed to increase our knowledge of the association by using international data from the Bladder Cancer Epidemiology and Nutritional Determinants Consortium.

METHODS

Individual data on 2,347 cases and 6,871 controls from 15 case-control studies with information on black, green, herbal, or general tea was pooled. The association was estimated using multilevel multivariable logistic regression analysis adjusted for multiple (non-)dietary factors.

RESULTS

Association between tea consumption and BC risk was observed (odds ratio, OR = 0.72, 95% confidence interval, 95% CI = 0.65-0.80) compared to non-tea drinkers. Stratified analyses based on gender and smoking status yielded similar results. Stratified analysis showed no significant association between black or green tea consumption and BC risk across models, while herbal tea consumption was linked to a reduced BC risk (OR = 0.59, 95% CI = 0.36-0.96). As daily tea consumption increased within a suitable range (<5.67 cups/day), BC risk decreased.

CONCLUSIONS

Camellia sinensis tea showed no association with BC risk, while herbal tea was inversely linked to BC incidence. Despite some significant findings in the selected strata, further studies are required to clarify the underlying mechanisms.

Is there a promoting role for artificial sweeteners in the evolution of bladder cancer? A meta-analysis of current literature

INTRODUCTION

Urinary bladder cancer is a frequent neoplasia in the urogenital system. Ageing and smoking are the two main risk factors, however, some chemical agents such as artificial sweeteners could act as initiators or promoters.

EVIDENCE ACQUISITION

After identifying trends in scientific literature, we conducted a wide search in PubMed database and a meta-analysis was performed on extracted data to determine the role of artificial sweeteners in the development of urinary bladder cancer.

EVIDENCE SYNTHESIS

Twenty-one full reports were enrolled from screening of PubMed database into final analysis involving 116,568 subjects in comparisons. Overall, 13,682 and 102,886 cases were identified for bladder cancer patients and healthy controls, respectively. Among artificial sweetener users, 12.5% was the incidence of bladder cancer. In the control group, 11.2% of cases suffered from urothelial carcinoma of the bladder. About 40.7% of the patients suffering from urinary neoplasms and 37.8% of the healthy cases were artificial sweetener users, respectively. There were only minor differences in overall descriptive data. The incidence of urinary bladder cancer among artificial sweetener users and control cases showed no risk difference (RD: 0.00, CI: -0.06 to 0.06). The frequency of artificial sweetener use among patients suffering from urinary bladder neoplasms and healthy subjects was compared which showed equal occurrences (OR: 0.96, CI: 0.79 to 1.17).

CONCLUSIONS

According to our results, the carcinogenic risk of artificial sweeteners is not proven. Saccharin should not be kept as a promoter in urothelial malignant transformation.

Non-sugar sweeteners and cancer: Toxicological and epidemiological evidence

Several toxicological and epidemiological studies were published during the last five decades on non-sugar sweeteners (NSS) and cancer. Despite the large amount of research, the issue still continues to be of interest. In this review, we provided a comprehensive quantitative review of the toxicological and epidemiological evidence on the possible relation between NSS and cancer. The toxicological section includes the evaluation of genotoxicity and carcinogenicity data for acesulfame K, advantame, aspartame, cyclamates, saccharin, steviol glycosides and sucralose. The epidemiological section includes the results of a systematic search of cohort and case-control studies. The majority of the 22 cohort studies and 46 case-control studies showed no associations. Some risks for bladder, pancreas and hematopoietic cancers found in a few studies were not confirmed in other studies. Based on the review of both the experimental data on genotoxicity or carcinogenicity of the specific NSS evaluated, and the epidemiological studies it can be concluded that there is no evidence of cancer risk associated to NSS consumption.

The relationship between the use of artificial sweeteners and cancer: A meta-analysis of case-control studies

Although there are reports that artificial sweeteners (AS) are safe, the relationship between artificial sweeteners and cancer remains controversial. The purpose of the study is to evaluate whether the consumption of artificial sweeteners is associated with the risk of cancers. We conducted a comprehensive search of multiple databases, including MEDLINE, EMBASE, Web of Science, and Cochrane Library. We found all the literature that studied the relationship between artificial sweeteners and cancer. Ten case-control studies were included in the meta-analysis. Our findings indicated that the consumption of artificial sweeteners was not associated with an increase in cancer when all types of cancers are analyzed comprehensively (OR 0.91, 95% CI 0.75-1.11). Interestingly, the use of artificial sweeteners is inversely related to urinary system cancer risk when analyzing women individually (OR 0.76, 95% CI 0.60-0.97). Our meta-analysis found that these is no correlation between artificial sweeteners and occurrence of cancer except urinary system cancer in women. Considering some limitations found in this study, additional data from large clinical trials are needed.

Association of dietary tomato intake with bladder cancer risk in a prospective cohort of 101,683 individuals with 12.5 years of follow-up

Previous studies have provided limited evidence for the effect of tomato intake on bladder cancer incidence. This study aimed to evaluate the association between dietary tomato or lycopene consumption and bladder cancer risk in the Prostate, Lung, Colorectal, and Ovarian Cancer (PLCO) Screening study. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox regression model adjusting for confounders. After a median of 12.5 years of follow-up, 774 incident bladder cancer cases were identified. We found no statistically significant association between dietary intake of raw tomatoes and bladder cancer risk (Adjusted model: HR_{Q5 VS Q1} = 1.20, 95% CI: 0.95-1.52; P for trend = 0.243). Dietary intakes of tomato catsup, tomato salsa and tomato juice were also not associated with the risk of bladder cancer (all P for trend > 0.05). There was no statistically significant association between dietary consumption of lycopene and bladder cancer risk (Adjusted model: HR_{Q5 vs. Q1} = 1.04, 95% CI 0.82-1.33; P for trend = 0.590). In summary, analysis of the PLCO study suggested that dietary consumption of tomato or lycopene was not associated with the risk of bladder cancer.

Association between intake of non-sugar sweeteners and health outcomes: systematic review and meta-analyses of randomised and non-randomised controlled trials and observational studies

OBJECTIVE

To assess the association between intake of non-sugar sweeteners (NSS) and important health outcomes in generally healthy or overweight/obese adults and children.

DESIGN

Systematic review following standard Cochrane review methodology.

DATA SOURCES

Medline (Ovid), Embase, Cochrane CENTRAL, WHO International Clinical Trials Registry Platform, Clinicaltrials.gov, and reference lists of relevant publications.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Studies including generally healthy adults or children with or without overweight or obesity were eligible. Included study designs allowed for a direct comparison of no intake or lower intake of NSS with higher NSS intake. NSSs had to be clearly named, the dose had to be within the acceptable daily intake, and the intervention duration had to be at least seven days.

MAIN OUTCOME MEASURES

Body weight or body mass index, glycaemic control, oral health, eating behaviour, preference for sweet taste, cancer, cardiovascular disease, kidney disease, mood, behaviour, neurocognition, and adverse effects.

RESULTS

The search resulted in 13 941 unique records. Of 56 individual studies that provided data for this review, 35 were observational studies. In adults, evidence of very low and low certainty from a limited number of small studies indicated a small beneficial effect of NSSs on body mass index (mean difference -0.6, 95% confidence interval -1.19 to -0.01; two studies, n=174) and fasting blood glucose (-0.16 mmol/L, -0.26 to -0.06; two, n=52). Lower doses of NSSs were associated with lower weight gain (-0.09 kg, -0.13 to -0.05; one, n=17 934) compared with higher doses of NSSs (very low certainty of evidence). For all other outcomes, no differences were detected between the use and non-use of NSSs, or between different doses of NSSs. No evidence of any effect of NSSs was seen on overweight or obese adults or children actively trying to lose weight (very low to moderate certainty). In children, a smaller increase in body mass index z score was observed with NSS intake compared with sugar intake (-0.15, -0.17 to -0.12; two, n=528, moderate certainty of evidence), but no significant differences were observed in body weight (-0.60 kg, -1.33 to 0.14; two, n=467, low certainty of evidence), or between different doses of NSSs (very low to moderate certainty).

CONCLUSIONS

Most health outcomes did not seem to have differences between the NSS exposed and unexposed groups. Of the few studies identified for each outcome, most had few participants, were of short duration, and their methodological and reporting quality was limited; therefore, confidence in the reported results is limited. Future studies should assess the effects of NSSs with an appropriate intervention duration. Detailed descriptions of interventions, comparators, and outcomes should be included in all reports.

SYSTEMATIC REVIEW REGISTRATION

Prospero CRD42017047668.

Non-Occupational Risk Factors for Bladder Cancer a Case-Control Study

Aims

The aim of this study was to determine non-occupational risk factors for bladder cancer in Serbia.

Methods and design

A hospital-based, case-control study included 130 newly diagnosed bladder cancer patients and the same number of individually matched controls with respect to sex, age (± 2 years) and type of residence (rural or urban), from the Clinical Center of Serbia in Belgrade and from the Clinical Center in Kragujevac in central Serbia. The study took place from June 1997 to March 1999.

Results

According to multivariate logistic regression analysis, there was an association between: frequency of daily urination (OR = 0.18; 95% CI = 0.08-0.39); consumption of liver (OR = 13.81; 95% CI = 2.49-76.69), canned meat (OR = 8.38; 95% CI = 1.74-40.36), fruit juices (OR = 0.08; 95% CI = 0.01-0.56); the highest fertile of pork (OR = 4.55; 95% CI = 1.30-15.93), cabbage (OR = 0.25; 95% CI = 0.06-1.01) and vinegar (OR = 4.41; 95% CI = 1.18-16.50) intake and risk for bladder cancer.

Conclusions

Consumption of liver, canned meat, pork (h vs I tertile) and vinegar (m vs I tertile) was indicated as a risk factor for bladder cancer, whereas frequent daily urination, consumption of fruit juices and cabbage (h vs I fertile) were indicated as protective factors.

Health outcomes of non-nutritive sweeteners: analysis of the research landscape

BACKGROUND

Food products containing non-nutritive sweeteners (NNSs) instead of sugar have become increasingly popular in the last decades. Their appeal is obviously related to their calorie-free sweet taste. However, with the dramatic increase in their consumption, it is reasonable and timely to evaluate their potential health benefits and, more importantly, potential adverse effects. The main aim of this scoping review was to map the evidence about health outcomes possibly associated with regular NNS consumption by examining the extent, range, and nature of research activity in this area.

METHODS

We systematically searched Ovid MEDLINE, EMBASE and the Cochrane CENTRAL databases for studies on NNSs (artificial sweeteners or natural, non-caloric sweeteners, either used individually or in combination) using text terms with appropriate truncation and relevant indexing terms. All human studies investigating any health outcomes of a NNS intervention or exposure were eligible for inclusion. No studies were excluded based on language, study design or methodological quality. Data for each health outcome were summarized in tabular form and were discussed narratively.

RESULTS

Finally, we included 372 studies in our scoping review, comprising 15 systematic reviews, 155 randomized controlled trials (RCTs), 23 non-randomized controlled trials, 57 cohort studies, 52 case-control studies, 28 cross sectional studies and 42 case series/case reports. In healthy subjects, appetite and short term food intake, risk of cancer, risk of diabetes, risk of dental caries, weight gain and risk of obesity are the most investigated health outcomes. Overall there is no conclusive evidence for beneficial and harmful effects on those outcomes. Numerous health outcomes including headaches, depression, behavioral and cognitive effects, neurological effects, risk of preterm delivery, cardiovascular effects or risk of chronic kidney disease were investigated in fewer studies and further research is needed. In subjects with diabetes and hypertension, the evidence regarding health outcomes of NNS use is also inconsistent.

CONCLUSIONS

This scoping review identifies the needs for future research to address the numerous evidence gaps related to health effects of NNSs use.It also specifies the research questions and areas where a systematic review with meta-analyses is required for the proper evaluation of health outcomes associated to regular NNSs consumption.

Tea Consumption and Risk of Bladder Cancer: A Dose-Response Meta-Analysis

Background and Objective: Controversial results of the association between tea (black tea, green tea, mate, and oolong tea) consumption and risk of bladder cancer were reported among epidemiological studies. Thus, we performed a meta-analysis of observational studies to investigate the association. Methods: We searched the PubMed and Embase for studies of tea consumption and bladder cancer that were published in any language up to March, 2016. Cohort or case-control studies were included in the meta-analysis. All statistical analyses were performed in Stata 12.0 software. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess the relationship between tea consumption and risk of bladder cancer. Results: Totally, 25 case-control studies (15 643 cases and 30 795 controls) and seven prospective cohort studies (1807 cases and 443 076 participants) were included. The meta-analysis showed that tea consumption was not significantly associated with bladder cancer risk (OR = 0.96, 95% CI 0.86-1.06) (in a comparison of highest vs. lowest category). No non-linearity association was observed between tea consumption and bladder cancer risk (P = 0.51 for non-linearity). Specific analysis for black tea, green tea, and mate yielded similar results. The dose-response analysis showed the summary OR for an increment of 1 cup/day of tea consumption was 1.01 (95% CI 0.97-1.05). Conclusion: Results based on current meta-analysis indicated that no significant association was observed between tea consumption and risk of bladder cancer.

Association of vitamin C, vitamin D, vitamin E and risk of bladder cancer: a dose-response meta-analysis

A dose-response meta-analysis was conducted to assess the association of vitamin C, D, E with risk of bladder cancer. Pertinent studies were identified in PubMed and Embase. The random-effect model was used. The relative risk (95% confidence interval) of bladder cancer was 0.99 (0.95–1.03) for every 100 IU/day increment in vitamin D from diet plus supplement and 0.95 (0.90–1.00) for every 10 nmol/L increment in circulating vitamin D. The effect for every 10 mg/day increment was 0.96 (0.90–1.02) for vitamin E from diet plus supplement, 0.83 (0.72–0.95) from diet and 0.88 (0.67–1.15) from supplement, and the effect was 0.84 (0.76–0.94) for every 1 mg/dL increment in circulating α-Tocopherol and 1.22 (1.00–1.49) for every 0.1 mg/dL increment in circulating γ-Tocopherol. The observed association for vitamin D and vitamin E was significant among smokers but not among non-smokers. No significant association was found between vitamin C and risk of bladder cancer in the dose-response analysis. Based on the dose-response analysis, the risk of bladder cancer might be inversely associated with vitamin D and E (especially α-Tocopherol), but positively associated with γ-Tocopherol.

Vitamin A and risk of bladder cancer: a meta-analysis of epidemiological studies

BACKGROUND

Epidemiological studies have reported the preventive effect of vitamin A intake on bladder cancer. However, the findings are inconsistent. To address this issue we conducted a meta-analysis to investigate the quantitative effects of vitamin A on bladder cancer.

METHODS

We searched MEDLINE and Embase databases and the references of the relevant articles in English to include studies on dietary or blood vitamin A for the risk of bladder cancer. We performed a meta-analysis using both fixed-effects and random-effects models.

RESULTS

Twenty-five articles on dietary vitamin A or blood vitamin A were included according to the eligibility criteria. The pooled risk estimates of bladder cancer were 0.82 (95% CI 0.65, 0.95) for total vitamin A intake, 0.88 (95% CI 0.73, 1.02) for retinol intake, and 0.64 (95% CI 0.38, 0.90) for blood retinol levels. We also found inverse associations between subtypes of carotenoids and bladder cancer risk.

CONCLUSION

The findings of this meta-analysis indicate that high vitamin A intake was associated with a lower risk of bladder cancer. Larger studies with prospective design and rigorous methodology should be considered to validate the current findings.

Coffee consumption and urologic cancer risk: a meta-analysis of cohort studies

OBJECTIVES

Controversial results were reported among several epidemiologic studies on the relationship between coffee consumption and urologic cancer risk. We, therefore, conducted this meta-analysis to clarify these associations.

METHODS

Electronic databases including Pubmed, Embase and Cochrane library were searched between January 1966 and August 2013 for eligible studies. Pooled relative risk (RR) and its 95 % confidence interval (CI) were calculated. All P values are two tailed.

RESULTS

Thirteen cohorts were eligible for inclusion. As to prostate cancer (PCa), significant reverse association was found among highest versus none/lowest analysis with acceptable heterogeneity (RR 0.86, 95 % CI 0.79-0.95; I(2) 25 %, P value for heterogeneity: 0.221). A pooled RR which assessed advanced PCa was 0.73 (with 95 % CI 0.50-1.07), and a slight stronger reverse association was found in fatal PCa. However, a slight insignificant reverse association, basing on 8 studies with 9 outcomes, was found in dose-response analysis (RR 0.98, 95 % CI 0.93-1.03). For kidney and bladder cancer, insignificant associations were found in both highest versus none/lowest analyses and dose-response analyses.

CONCLUSIONS

Our findings suggest that coffee consumption may reduce the risk of PCa. No associations were found with both bladder and kidney cancer. Further well-designed large-scaled cohort studies are warranted to provide more definitive conclusions.

Chemoprevention of superficial bladder cancer

The American Cancer Society estimates that 57,400 new cases of bladder cancer will be diagnosed in the USA in 2003 and that approximately 70% of these cases will be superficial bladder tumors. Due to the high risk of recurrence, patients with superficial bladder cancer represent an ideal group for chemoprevention. Intravesical chemotherapy or immunotherapy is often administered in an attempt to prevent tumor recurrence in high-risk patients, although it is not without toxicity. A large body of evidence links diet and nutrition with bladder cancer. This review summarizes the efficacy of natural and synthetic agents that have purported chemopreventive activity.

Tea consumption and risk of bladder cancer: a meta-analysis

Background

Tea consumption has been reported to be associated with an decreased risk of several types of cancers. However, the results based on epidemiological studies on the association of tea consumption with bladder cancer were inconsistent. This meta-analysis was undertaken to evaluate the relationship between tea consumption and bladder cancer risk.

Methods

Eligible studies were retrieved via both computer searches and review of references. The summary relative risk (RR) with 95% confidence interval (CI) was calculated.

Results

Twenty three studies met the inclusion criteria of the meta-analysis. No association with bladder cancer was observed in either overall tea consumption group (OR =0.94, 95% CI 0.85-1.04) or subgroups stratified by sex, study design, geographical region or tea types.

Conclusions

Our findings did not support that tea consumption was related to the decreased risk of bladder cancer.

Fruit and vegetable consumption and risk of aggressive and non-aggressive urothelial cell carcinomas in the European Prospective Investigation into Cancer and Nutrition

BACKGROUND

Many epidemiological studies have examined fruit and vegetable consumption in relation to the risk of urothelial cell carcinoma (UCC) of the bladder, but results are inconsistent. The association between fruit and vegetable consumption and UCC risk may vary by bladder tumour aggressiveness. Therefore, we examined the relation between fruit and vegetable consumption and the risk of aggressive and non-aggressive UCC in the European Prospective Investigation into Cancer and Nutrition (EPIC).

METHODS

After 8.9 years of follow-up, 947UCC were diagnosed among 468,656 EPIC participants. Of these, 421 could be classified as aggressive UCC and 433 as non-aggressive UCC cases. At recruitment, fruit and vegetable consumption was assessed by validated dietary questionnaires. Multivariable hazard ratios were estimated using Cox regression stratified by age, sex and center and adjusted for smoking status, duration and intensity of smoking, and energy intake.

RESULTS

Total consumption of fruits and vegetables was not associated with aggressive UCC nor with non-aggressive UCC. A 25 g/day increase in leafy vegetables and grapes consumption was associated with a reduced risk of non-aggressive UCC (hazard ratio (HR) 0.88; 95%confidence interval (CI) 0.78-1.00 and HR 0.87; 95%CI 0.77-0.98, respectively), while the intake of root vegetables was inversely associated with risk of aggressive UCC (HR 0.87; 95%CI 0.77-0.98).

CONCLUSION

Our study did not confirm a protective effect of total fruit and/or vegetable consumption on aggressive or non-aggressive UCC. High consumption of certain types of vegetables and of fruits may reduce the risk of aggressive or non-aggressive UCC; however chance findings cannot be excluded.

A dose-response meta-analysis of coffee consumption and bladder cancer

BACKGROUND

A number of studies have examined the association between coffee consumption and risk of bladder cancer, but uncertainty about the dose-response relationship remains.

MATERIALS AND METHODS

A comprehensive search was performed to identify all observational studies providing quantitative estimates between bladder cancer risk and coffee consumption. Dose-response relationship was assessed by restricted cubic spline model and bivariate random-effect meta-regression.

RESULTS

23 case-control studies with 7690 cases and 13,507 controls, and 5 cohort studies with 700 cases and 229,099 participants, met the inclusion criteria. Compared with non-drinkers and for case-control studies, the pooled smoking-adjusted RRs(95% CI) of bladder cancer were 1.07(1.02-1.13) for 1 cup/day, 1.15(1.05-1.26) for 2 cups/day, 1.22(1.08-1.38) for 3 cups/day, and 1.29(1.12-1.48) for 4 cups/day. For cohort studies, the pooled smoking-adjusted RRs of bladder cancer were 1.09(95% CI, 0.89-1.34) for 1 cup/day, 1.13(95% CI, 0.82-1.55) for 2 cups/day, 1.09(95% CI, 0.77-1.56) for 3 cups/day, and 1.01(95% CI, 0.69-1.48) for 4 cups/day.

CONCLUSIONS

Although data from case-control studies suggested that coffee was a risk factor for bladder cancer, there was no conclusive evidence on this association because of inconsistencies between case-control and cohort studies.

Dietary intake of meat, fruits, vegetables, and selective micronutrients and risk of bladder cancer in the New England region of the United States

Background:

Despite many studies on diet and bladder cancer, there are areas that remain unexplored including meat mutagens, specific vegetable groups, and vitamins from diet.

Methods:

We conducted a population-based case–control study of bladder cancer in Maine, New Hampshire, and Vermont. A total of 1171 cases were ascertained through hospital pathology records and cancer registries from 2001 to 2004. Overall, 1418 controls were identified from the Department of Motor Vehicles (<65 years) and Center for Medicaid and Medicare Services (65–79 years) and were frequency-matched to cases by state, sex, and age (within 5 years). Diet was assessed with a self-administered Diet History Questionnaire. Unconditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI).

Results:

Processed meat intake was positively associated with bladder cancer (highest vs lowest quartile OR: 1.28; 95% CI: 1.00–1.65; P_trend=0.035), with a stronger association for processed red meat (OR: 1.41; 95% CI: 1.08–1.84; P_trend=0.024). There were no associations between intake of fruits or vegetables and bladder cancer. We did, however, observe an inverse association with vitamin B12 intake (OR: 0.77; 95% CI: 0.61–0.99; P=0.019).

Conclusion:

Vitamin B12 from diet may be protective against bladder cancer, whereas consuming processed meat may increase risk.

Pathobiology and chemoprevention of bladder cancer

Our understanding of the pathogenesis of bladder cancer has improved considerably over the past decade. Translating these novel pathobiological discoveries into therapies, prevention, or strategies to manage patients who are suspected to have or who have been diagnosed with bladder cancer is the ultimate goal. In particular, the chemoprevention of bladder cancer development is important, since urothelial cancer frequently recurs, even if the primary cancer is completely removed. The numerous alterations of both oncogenes and tumor suppressor genes that have been implicated in bladder carcinogenesis represent novel targets for therapy and prevention. In addition, knowledge about these genetic alterations will help provide a better understanding of the biological significance of preneoplastic lesions of bladder cancer. Animal models for investigating bladder cancer development and prevention can also be developed based on these alterations. This paper summarizes the results of recent preclinical and clinical chemoprevention studies and discusses screening for bladder cancer.

Chemoprevention in bladder cancer: What's new?

Bladder cancer is the sixth most common tumour in Canada and ranks eighth in terms of cancer mortality. Up to now, management of this condition relied mostly on surgical and intravesical treatments once the disease is established. Chemoprevention is an attractive option to prevent the disease in high-risk populations and may well reduce the costs related to its treatment. This review examines the available data on chemoprevention strategies in bladder cancer, with special emphasis on randomized controlled trials when available.

Minerals and vitamins and the risk of bladder cancer: results from the New Hampshire Study

Objective

Although the effect of fruit and vegetables on the risk of bladder cancer has been widely studied, little is known about their micronutrient components. Our aim was to investigate associations between minerals and vitamins and bladder cancer.

Methods

A case–control study was conducted in New Hampshire, USA. Dietary data were collected from 322 cases and 239 controls using a 121-item food frequency questionnaire. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using logistic regression adjusting for sex, age, smoking characteristics, and energy intake.

Results

The ORs (95% CI) for highest quartile versus lowest quartile for total intake of vitamin E was 0.66 (0.36–1.20; p trend = 0.09) and 0.49 (0.21–1.17; p trend = 0.13) for dietary phosphorus. The odds of bladder cancer for heavy smokers with the highest total intake of vitamin E, carotenoids, and niacin were 0.58 (0.34–0.99), 0.62 (0.36–1.09), and 0.66 (0.39–1.14), respectively. Higher total intakes of carotenoids, vitamin D, thiamin, niacin, and vitamin E were inversely related to bladder cancer risk among older individuals.

Conclusion

Our findings suggest further investigation of the effect of vitamin E, carotenoids, vitamin D, thiamin, and niacin on bladder cancer risk may be warranted. Future studies should focus on high risk groups such as heavy smokers and older individuals.

Dietary intake of vegetables and fruits and the modification effects of GSTM1 and NAT2 genotypes on bladder cancer risk

We analyzed the association between intakes of vegetables and fruits as defined by the U.S. Department of Agriculture pyramid food groups and bladder cancer risk using data collected in a large case-control study. The study included 884 histologically confirmed bladder cancer cases and 878 healthy controls matched to cases by age (+/-5 years), gender, and ethnicity. Significant inverse associations were observed for intakes of total vegetables, cruciferous vegetables, orange vegetables, dark green vegetables, and bladder cancer risk. Compared with those in the lowest quartile of total vegetable intake, the odds ratios for the 2nd, 3rd, and 4th quartiles of total vegetable intake were 0.84 [95% confidence interval (95% CI), 0.64-1.10], 0.71 (95% CI, 0.54-0.95), and 0.67 (95% CI, 0.50-0.90), respectively (P for trend = 0.004). Compared with those in the lowest quartile, those in the highest quartile of cruciferous vegetable intake had an odds ratio of 0.69 (95% CI, 0.52-0.92; P for trend = 0.001) and those in the highest quartile of orange vegetable intake had an odds ratio of 0.68 (95% CI, 0.52-0.91; P for trend = 0.006). Furthermore, the protective effect of cruciferous vegetables was more evident in subjects carrying GSTM1-null (odds ratio, 0.43; 95% CI, 0.25-0.73 for the 4th quartile of intake) and NAT2-slow genotypes (odds ratio, 0.56; 95% CI, 0.33-0.97 for the 4th quartile of intake). No association was observed for intakes of total fruits or citrus fruits. Our data strongly support that high vegetable consumption, especially cruciferous vegetable intake, may protect against bladder cancer and that genetic variants of GSTM1 and NAT2 may modify the association.

Liposome encapsulation of curcumin and resveratrol in combination reduces prostate cancer incidence in PTEN knockout mice

Increasing interest in the use of phytochemicals to reduce prostate cancer led us to investigate 2 potential agents, curcumin and resveratrol as preventive agents. However, there is concern about the bioavailability of these agents pertinent to the poor absorption and thereby limiting its clinical use. With the view to improve their bioavailability, we used the liposome encapsulated curcumin, and resveratrol individually and in combination in male B6C3F1/J mice. Further, we examined the chemopreventive effect of liposome encapsulated curcumin and resveratrol in combination in prostate-specific PTEN knockout mice. In vitro assays using PTEN-CaP8 cancer cells were performed to investigate the combined effects curcumin with resveratrol on (i) cell growth, apoptosis and cell cycle (ii) impact on activated p-Akt, cyclin D1, m-TOR and androgen receptor (AR) proteins involved in tumor progression. HPLC analysis of serum and prostate tissues showed a significant increase in curcumin level when liposome encapsulated curcumin coadministered with liposomal resveratrol (p < 0.001). Combination of liposomal forms of curcumin and resveratrol significantly decreased prostatic adenocarcinoma in vivo (p < 0.001). In vitro studies revealed that curcumin plus resveratrol effectively inhibit cell growth and induced apoptosis. Molecular targets activated due to the loss of phosphatase and tensin homolog (PTEN) including p-Akt, cyclin D1, mammalian target of rapamycin and AR were downregulated by these agents in combination. Findings from this study for the first time provide evidence on phytochemicals in combination to enhance chemopreventive efficacy in prostate cancer. These findings clearly suggest that phytochemicals in combination may reduce prostate cancer incidence due to the loss of the tumor suppressor gene PTEN.

Alcohol, coffee, and bladder cancer risk: a review of epidemiological studies

The objective was to review epidemiological studies that evaluated the association between consumption of coffee and alcohol and urinary bladder cancer. We searched the Medline database for observational studies of bladder neoplasms that included information on coffee or alcohol drinking, and looked for papers quoted as references in reviews of risk factors for bladder cancer and in studies that had been selected for inclusion. Results from epidemiological studies allow excluding a strong association between coffee and bladder cancer. Several studies reported a moderate increase in risk in coffee drinkers as compared with nondrinkers, but no trend with dose has been established. Epidemiological data on alcohol drinking and bladder cancer are suggestive of no association, although findings were not always consistent. For both habits, an explanation of the moderate increase in risk observed in some investigations might be attributed to residual confounding by smoking, or to an association between alcohol, coffee, and yet unidentified risk factors for bladder cancer.

Coffee and alcohol consumption and bladder cancer

Epidemiological studies on coffee, alcohol and bladder cancer risk published up to 2007 were reviewed. Coffee drinkers have a moderately higher relative risk of bladder cancer compared to non-drinkers. The association may partly be due to residual confounding by smoking or dietary factors, but the interpretation remains open to discussion, although the absence of dose and duration-risk relations weighs against the presence of a causal association. Most studies of alcohol and bladder cancer found no association, with some studies finding a direct and other an inverse one. This again may be due to differential confounding effect of tobacco smoking--the major risk factor for bladder cancer--in various populations. Thus, epidemiological findings on the relation between alcohol drinking and bladder cancer exclude any meaningful association.

Coffee, green tea, and caffeine consumption and subsequent risk of bladder cancer in relation to smoking status: a prospective study in Japan

Coffee and caffeine consumption are thought to increase the risk of bladder cancer. However, few studies have stratified this risk by smoking status, which is a potential confounder. Here, we investigated the association between coffee, green tea (another major source of caffeine), and caffeine, and bladder cancer incidence in relation to smoking status. We conducted a population-based prospective study in a cohort of Japanese, comprising a total of 49 566 men and 54 874 women aged 40–69 years who reported their coffee and green tea consumption at baseline. During follow-up from 1990 through 2005, 164 men and 42 women were newly diagnosed with bladder cancer. Cigarette smoking was associated with an increased risk of bladder cancer, with a strong dose–response relationship. Coffee was positively associated with bladder cancer risk in men, without statistical significance. When stratified by smoking status, coffee and caffeine consumption were associated with an increased risk of bladder cancer in never- or former-smoking men, with hazard ratios (95% confidence interval) in the highest categories of coffee (one or more cups per day) and caffeine consumption compared with the lowest of 2.24 (95% CI = 1.21–4.16) and 2.05 (95% CI = 1.15–3.66), respectively. In conclusion, cigarette smoking was confirmed as a risk factor for bladder cancer. Coffee and caffeine may be associated with an increased bladder cancer risk in never or former smokers among Japanese men.

Lycopene in cancer prevention and treatment

Dietary intake of lycopene is inversely associated with the risk of many cancers. Preclinical studies show that lycopene has potent in vitro and in vivo antitumor effects, suggesting potential preventive and therapeutic roles for the compound. However, clinical trials with lycopene have only recently been started, and available clinical data preclude firm conclusions with regard to its use in cancer prevention and treatment. Further mechanistic studies and randomized controlled clinical intervention trials with lycopene involving cancer patients are warranted.

Urinary bladder cancer risk factors in men: a Spanish case–control study

The rising incidence of urinary bladder cancer is alarming and potential relationships with different risk factors have been postulated. The purpose of this study was to examine the possible relationship between different environmental risk factors and urinary bladder cancer. All men with urinary bladder cancer who were admitted to the Department of Urology of Reina Sofia University Hospital of Cordoba, Spain over 1 year were included in our study. Men were administered an interview questionnaire, which included data on history of known urinary bladder cancer risk factors. Comparisons between men with urinary bladder cancer (cases) and those with nonmalignant urological disease (controls) were made. The study included 74 cases and 89 controls. The variables associated with malignant lesions on univariate analysis were age, smoking and drinking alcohol. Meanwhile, fish, poultry and beef consumption were proved to be protective factors. The risk factors identified by the logistic regression analysis were age, smoking and fluid intake. The independent protective factors on the multivariate analysis were fish and poultry consumptions. Smoking was found to be the principal independent risk factors for urinary bladder cancer. Our results call for further investigation of urinary bladder cancer risk factors; future studies should preferably be performed on large prospective cohorts, to increase their validity.

Chemoprevention for Bladder Cancer

PURPOSE

Bladder cancer is the most expensive cancer to treat and follow in the United States due to often extended courses of treatment coupled with the necessity for frequent surveillance examinations. Because direct exposure to carcinogens is implicated in bladder cancer development and many potentially protective compounds are concentrated in urine, bladder cancer is a logical target for chemoprevention.

MATERIALS AND METHODS

We performed a MEDLINE search of the English language literature to identify reports of chemoprevention of bladder cancer. Study outcomes were evaluated and mechanisms of action were identified when possible. In cases of multiple reports of the same compound critical comparisons were performed.

RESULTS

For most putative chemopreventive agents against bladder cancer the results of different studies are conflicting. Megadose vitamins, certain vitamin A analogues and pyridoxines have been associated with promising findings. For vitamins C and E and selenium, studies showing benefit are balanced by studies showing no benefit. Other compounds, such as soy, green tea and isothiocyanates, have been suggested by some studies to be protective and by others to be tumor promoting.

CONCLUSIONS

For most bladder cancer chemopreventive agents studied to date results regarding efficacy vary, precluding the possibility of universal support by health care providers for this specific role. Megadose multivitamin supplements have demonstrated the ability to prevent bladder cancer recurrences in a single smaller study. Some analogues of vitamins A, B6, C and E have been shown to be beneficial in other disease processes, suggesting that these compounds may be advocated with the caveat that they do not have a specific protective role in bladder cancer. Data from randomized, prospective trials show a benefit in bladder cancer only after eliminating early or initial recurrences, suggesting the need for long-term administration of a chosen agent. Additional prospective trials with long-term followup, likely involving multiple institutions, are required before definitive recommendations can be made about chemoprevention for bladder cancer. In 2006 no oral agent can be recommended and to our knowledge the best chemopreventive strategy remains to be determined.

Prevention of Bladder Cancer: A Review

INTRODUCTION

Bladder cancer represents an ideal tumor model to test and apply cancer prevention strategies. In addition to reviewing the epidemiology of transitional cell carcinoma (TCC), we review the current status and the future directions of bladder cancer prevention.

MATERIALS AND METHODS

A literature review of peer-reviewed articles which address bladder cancer prevention was performed.

RESULTS

Pre-clinical and limited clinical data suggest that bladder cancer is responsive to efforts to delay or prevent its development in at-risk patients, and in reducing the risk of recurrence in patients with established disease. Many epidemiologic studies, however, investigating natural products, such as vitamins and herbal compounds, lack conclusive evidence of their chemopreventive effects.

CONCLUSIONS

While many agents hold promise in the prevention of bladder cancer, none currently can be recommended as proven chemoprevention strategies. Improving the accuracy of patient risk assessment and identification of surrogate endpoint biomarkers are crucial to the testing of these strategies. Efficient study design will ensure rapid and substantial advances in the chemoprevention of bladder cancer.

Intake of Fruits and Vegetables, Carotenoids, Folate, and Vitamins A, C, E and Risk of Bladder Cancer Among Women (United States)

OBJECTIVE

To examine the relation between fruits and vegetables, carotenoids, folate, and vitamins A, C, E and the risk of bladder cancer in a prospective study of women.

METHODS

A total of 237 incident bladder cancer cases were documented during 20 years of follow-up among 88,796 women enrolled in the Nurses' Health Study. Dietary intake was assessed by food-frequency questionnaires every two to four years and incident diagnosis of bladder cancer was ascertained every two years. Cox proportional hazard models were used to estimate incidence rate ratios (RR) and 95% confidence intervals (CI) for bladder cancer risk, adjusting for age, pack-years of smoking, current smoking, and total caloric intake.

RESULTS

Consumption of total fruits and vegetables was not associated with bladder cancer risk (RR = 1.08, 95% CI = 0.70-1.65, for > 5.5 compared to < 2.5 servings per day). Similarly, dietary intakes of carotenoids, folate, and vitamins A, C, E, were not related to bladder cancer risk. No association was observed between supplemental intake of multivitamins, vitamins A, C, E and bladder cancer risk.

CONCLUSIONS

We did not observe any association for fruit and vegetable consumption or vitamin intake and bladder cancer risk among women.

Carotenoid actions and their relation to health and disease

Based on extensive epidemiological observation, fruits and vegetables that are a rich source of carotenoids are thought to provide health benefits by decreasing the risk of various diseases, particularly certain cancers and eye diseases. The carotenoids that have been most studied in this regard are beta-carotene, lycopene, lutein and zeaxanthin. In part, the beneficial effects of carotenoids are thought to be due to their role as antioxidants. beta-Carotene may have added benefits due its ability to be converted to vitamin A. Additionally, lutein and zeaxanthin may be protective in eye disease because they absorb damaging blue light that enters the eye. Food sources of these compounds include a variety of fruits and vegetables, although the primary sources of lycopene are tomato and tomato products. Additionally, egg yolk is a highly bioavailable source of lutein and zeaxanthin. These carotenoids are available in supplement form. However, intervention trials with large doses of beta-carotene found an adverse effect on the incidence of lung cancer in smokers and workers exposed to asbestos. Until the efficacy and safety of taking supplements containing these nutrients can be determined, current dietary recommendations of diets high in fruits and vegetables are advised.

Evaluation of the effect of dietary vegetable consumption on reducing risk of transitional cell carcinoma of the urinary bladder in Scottish Terriers

OBJECTIVE

To evaluate the effects of vegetable consumption and vitamin supplementation on the risk of developing transitional cell carcinoma (TCC) of the urinary bladder in Scottish Terriers.

DESIGN

Case-control study.

ANIMALS

92 adult Scottish Terriers with TCC (cases) and 83 Scottish Terriers with other conditions (controls).

PROCEDURE

Owners of dogs with TCC completed a questionnaire regarding their dogs' diet and intake of vitamin supplements in the year prior to diagnosis of TCC; owners of control dogs completed the questionnaire for a comparable time period. The risk (odds ratio [OR]) of developing TCC associated with diet and vitamin supplementation was determined by use of logistic regression.

RESULTS

After adjustment for age, weight, neuter status, and coat color, there was an inverse association between consumption of vegetables at least 3 times/wk (OR, 0.30; 95% confidence interval [CI], 0.15 to 0.62) and risk of developing TCC. For individual vegetable types, the risk of developing TCC was inversely associated with consumption of green leafy vegetables (OR, 0.12; 95% CI, 0.01 to 0.97) and yellow-orange vegetables (OR, 0.31; 95% CI, 0.14 to 0.70). Consumption of cruciferous vegetables was not significantly associated with a similar reduction in risk of developing TCC (OR, 0.22; CI, 0.04 to 1.11). The power of the study to detect a 50% reduction in TCC risk associated with daily vitamin supplementation was considered low (25%).

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that consumption of certain vegetables may prevent or slow the development of TCC in Scottish Terriers.

Diet and Bladder Cancer: A Case–Control Study

To investigate possible relationships between diet and risk for bladder cancer in Serbia, the hospital-based case-control study was carried out. This study included 130 newly diagnosed bladder cancer patients and the same number of controls matched by sex, age (%+/-%2 years) and type of residence (rural or urban). Dietary information was obtained by using a food frequency questionnaire. Initial case-control comparisons were based on tertiles of average daily intake of control group. The odds ratios (ORs) were computed for each tertile, with the lowest tertile defined as the referent category. All variables (food items) significantly related to bladder cancer were included in multivariable logistic regression analysis. According to this analysis, risk factors for bladder cancer appeared to be consumption of liver (OR=6.60, 95%CI=1.89-23.03), eggs (OR=3.12, 95%CI=1.10-8.80), pork (OR=2.99, 95%CI=1.16-7.72), and pickled vegetable (OR=3.25, 95%CI=1.36-7.71). A protective effect was found for dietary intake of kale (OR=0.21, 95%CI=0.06-0.73), cereals (OR=0.19, 95%CI=0.06-0.62), tangerines (OR=0.21, 95%CI=0.07-0.68), cabbage (OR=0.27, 95% CI=0.11-0.68), and carrots (OR=0.15, 95%CI=0.05-0.41). The study indicated a potentially important role for dietary fat and pickled vegetables in bladder carcinogenesis. An inverse association was recorded between consumption of fruits, vegetables and cereals, and the development of bladder cancer.

[Diet in bladder cancer ethiopathogenesis]

The aim of this paper is to show influence of different foods on bladder cancer appearance, as well as possible consequent ways of prevention. Consuption of food rich in animal fat and cholesterol, fried foods, especially several times used cookin oil for frying, processed meat with additives (nitrates, nitrites, azo-colourrs) can influence bladder cancer occurrence. Regularly, continous consumption of fermented milk products, which contains come types of milky--acids bacterias, is considered as protective factor in developing bladder cancer. Reports that fruit and vegetable are protective food items are pretty consistent. Data about mineral intake and bladder cancer are obscure.

Carotenoids/vitamin C and smoking-related bladder cancer

Previous epidemiological studies of fruit and vegetable intake and bladder cancer risk have yielded inconsistent results, especially with respect to the role of cigarette smoking as a possible modifier of the diet-bladder cancer association. A population-based case-control study was conducted in nonAsians of Los Angeles, California, which included 1,592 bladder cancer patients and an equal number of neighborhood controls matched to the index cases by sex, date of birth (within 5 years) and race between January 1, 1987 and April 30, 1996. Information on smoking, medical and medication history, and intake frequencies of food groups rich in preformed nitrosamines, vitamins A and C and various carotenoids, were collected through in-person, structured interviews. Beginning in January 1992, all case patients and their matched control subjects were asked for a blood sample donation at the end of the in-person interviews for measurements of 3- and 4-aminobiphenyl (ABP) hemoglobin adducts, and glutathione S-transferases M1/T1/P1 (GSTM1/T1/P1) and N-acetyltransferase-1 (NAT1) genotypes. Seven hundred seventy-one (74%) case patients and 775 (79%) control subjects consented to the blood donation requests. In addition, all case patients and matched control subjects were asked to donate an overnight urine specimen following caffeine consumption for measurements of cytochrome P4501A2 (CYP1A2) and N-acetyltransferase-2 (NAT2) phenotypes. Urine specimens were collected from 724 (69%) case patients and 689 (70%) control subjects. After adjustment for nondietary risk factors including cigarette smoking, there were strong inverse associations between bladder cancer risk and intake of dark-green vegetables [p value for linear trend (p) = 0.01], yellow-orange vegetables (p = 0.01), citrus fruits/juices (p = 0.002) and tomato products (p = 0.03). In terms of nutrients, bladder cancer risk was inversely associated with intake of both total carotenoids (p = 0.004) and vitamin C (p = 0.02). There was a close correlation (r = 0.58, p = 0.0001) between intakes of total carotenoids and vitamin C in study subjects. When both nutrients were included in a multivariate logistic regression model, only total carotenoids exhibited a residual effect that was of borderline statistical significance (p = 0.07 and p = 0.40 for total carotenoids and vitamin C, respectively). Cigarette smoking was a strong modifier of the observed dietary effects; these protective effects were confined largely to ever smokers and were stronger in current than ex-smokers. Smokers showed a statistically significant or borderline statistically significant decrease in 3- and 4-aminobiphenyl (ABP)-hemoglobin adduct level with increasing intake of carotenoids (p = 0.04 and 0.05, respectively). The protective effect of carotenoids on bladder cancer seemed to be influenced by NAT1 genotype, NAT2 phenotype and CYP1A2 phenotype; the association was mainly confined to subjects possessing the putative NAT1-rapid, NAT2-rapid and CYP1A2-rapid genotype/phenotype. The carotenoid-bladder cancer association was not affected by the GSTM1, GSTT1 and GSTP1 genotypes.

The association between smoking, beverage consumption, diet and bladder cancer: a systematic literature review

In this paper the association between smoking history, beverage consumption, diet and bladder cancer incidence is systematically reviewed. A rating system has been used to summarise the level of scientific evidence (i.e. convincing, probable, possible, and no evidence) and the level of association (i.e. substantially increased, (RR> or =2.5), moderately increased (1.5< or =RR<2.5), slightly increased (1.2< or =RR<1.5), no association (0.8< or =RR<1.2), slightly decreased (0.7< or =RR<0.8), moderately decreased (0.4< or =RR<0.7), and substantially decreased (RR<0.4)). There is convincing evidence that cigarette smoking status, frequency and duration substantially increase the risk of bladder cancer. However, the evidence is not clear for other forms of smoking. A small increased risk for cigar, pipe, and environmental smoking is only possible. There is possible evidence that total fluid intake is not associated with bladder cancer. Although there is convincing evidence for a positive association between alcohol consumption and bladder cancer risk in men, the risk is small and not clinically relevant. Coffee and tea consumption are probably not associated with bladder cancer. The authors conclude that total fruit consumption is probably associated with a small decrease in risk. There is probably no association between total vegetable intake, vitamin A intake, vitamin C intake and bladder cancer and a possibly moderate inverse association with vitamin E intake. Folate is possibly not associated with bladder cancer. There probably is a moderate inverse association between selenium intake and bladder cancer risk.

Bladder cancer prevention. Part I: what do I tell my patients about lifestyle changes and dietary supplements?

PURPOSE OF REVIEW

Comprehensive reviews of lifestyle changes and dietary supplements that may prevent bladder cancer are needed in order to facilitate discussions between clinicians and patients.

RECENT FINDINGS

Novel data exist that numerous lifestyle/diet and dietary supplements may lower the risk of this disease. For example, reducing arsenic exposure, incorporating dietary changes, and vitamin E supplements continue to accumulate research that supports their use with some patients at a higher risk for this disease. Regardless, smoking cessation seems to have the largest impact on reducing risk and incorporating these other changes after smoking cessation may reduce an individual's risk to an even greater extent.

SUMMARY

However, a large percentage of cases of individuals diagnosed with this cancer apparently have no known etiology. Diets lower in calories or possibly specific sub-types of fat, and higher in fruits and especially vegetables, seem to provide some protection. Other dietary/supplement options may affect risk, but these benefits could be seriously attenuated by smoking. Dietary selenium, but currently not selenium supplements, may also affect risk, especially in non-smokers. Dietary vitamin E, and vitamin E supplements, may provide some protection. Non-selective (e.g. non-steroidal anti-inflammatory drugs) and selective cyclooxygenase-2 inhibitors are generating interest because bladder tumors seem to contain higher concentrations of this enzyme. Drinking-water quality, especially arsenic concentrations, may seriously affect risk. Providing recommendations for patients with regard to some of these lifestyle modifications is currently recommended because the majority of these alterations are also recommended currently for cardiovascular or general oncology disease reduction.

Chemoprevention of carcinoma prostate: a review

PURPOSE

Chemoprevention of prostate cancer is the administration of agents to prevent, inhibit, or delay progression of prostate cancer. Opportunities exist for testing various types of chemopreventive interventsion.

MATERIAL AND METHODS

The authors reviewed the relevant articles published in the last twenty years and studied the biology of the prostate cancer. An attempt is made to identify intermediate markers and surrogate endpoint markers. The various interventions and initial clinical trial results are described. End points for evaluation are mainly based on changes in PSA, changes of histological precursors, or time of onset of clinical disease.

RESULTS

Nutritional factors such as reduced fat intake, vitamin A, vitamin E, vitamin C, vitamin D, Lycopene and selenium may have a protective effect against prostate cancer.

CONCLUSION

Numerous studies implicate dietary and nutritional factors in the onset and progression of prostate cancer. Hence, it is possible that bioactive compounds (anti-oxidants) like vits. A, C, D, E, minerals like selenium and carotenoids like lycopene can be a part of chemopreventive strategies for prostate cancer. Ongoing studies on nutrition and prostate cancer may bring the required evidence to support what is still only a hypothesis at present. However, absolute recommendation will have to await the results of long term prospective clinical trials.

Chemoprevention of superficial bladder cancer

Patients who have bladder cancer with superficial disease are at high risk for recurrence but low risk for progression to muscle invasive disease and are regularly monitored with cystoscopy to detect recurrent tumors. This clinical setting (high recurrence rate, excellent surveillance, and low risk of progression in stage) provides an ideal setting for secondary chemoprevention. Vitamins, difluoromethylornithine, and cyclooxygenase inhibitors have demonstrated activity in preclinical models of bladder cancer. Limited clinical data suggests that vitamins and their analogs may be useful for decreasing the rate of tumor recurrence in patients with superficial bladder cancer. Ongoing clinical trials are exploring the roles of fenretinide, difluoromethylornithine, and celecoxib in the treatment of patients with a history of superficial bladder cancer.

The role of nutrition in preventing prostate cancer: a review of the proposed mechanism of action of various dietary substances

BACKGROUND

Dietary modifications to prevent prostate cancer (PCa) continue to gain attention as research demonstrates that various dietary nutrients/supplements are related to decreased risk of developing prostate cancer (PCa). Several studies have focused on the antioxidant and nonantioxidant effects of various dietary substances in the prevention of PCa. Research into the mechanisms by which PCa is prevented, or its disease severity is reduced by dietary micronutrients and vitamins continues to enrich our understanding of the mechanisms by which PCa is initiated and progresses.

METHODS

We reviewed the literature on dietary nutrients with antioxidant properties that have been shown to have a positive effect in reducing the incidence or preventing the occurrence of PCa including carotenoids (e.g., lycopene), retinoids (e.g., vitamin A), vitamin E, vitamin C, selenium, and polyphenols. Other nutrients examined included vitamin D and calcium.

RESULTS

Many dietary micronutrients have demonstrated significant and complex effects on PCa cell proliferation, differentiation, and signaling related to the initiation, progression, and regression of PCa.

CONCLUSION

Understanding the mechanisms by which various dietary nutrients exert their effects on PCa may make it possible to design effective drugs for treating PCa and to promote better nutrition and lifestyle changes in those at risk for PCa.

The role of carotenoids in human health

Dietary carotenoids are thought to provide health benefits in decreasing the risk of disease, particularly certain cancers and eye disease. The carotenoids that have been most studied in this regard are beta-carotene, lycopene, lutein, and zeaxanthin. In part, the beneficial effects of carotenoids are thought to be due to their role as antioxidants. beta-Carotene may have added benefits due its ability to be converted to vitamin A. Furthermore, lutein and zeaxanthin may be protective in eye disease because they absorb damaging blue light that enters the eye. Food sources of these compounds include a variety of fruits and vegetables, although the primary sources of lycopene are tomato and tomato products. Additionally, egg yolk is a highly bioavailable source of lutein and zeaxanthin. These carotenoids are available in supplement form. However, intervention trials with large doses of beta-carotene found an adverse effect on the incidence of lung cancer in smokers and workers exposed to asbestos. Until the efficacy and safety of taking supplements containing these nutrients can be determined, current dietary recommendations of diets high in fruits and vegetables are advised.

Chemoprevention of bladder cancer

The data presented herein, although highly supportive for a protective role of various nutrients against bladder cancer, are far from definitive. Many authorities question the validity of current recommendations for nutritional chemoprevention against bladder cancer. The reason for the wide variations reported in epidemiologic studies lies in the nature of observational studies. Dietary studies are limited in their conclusions because the protection afforded by the consumption of a particular nutrient may be multifactorial, with different components of the food exerting potential chemopreventive effects. Furthermore, measuring levels of nutrients in the food intake of populations is confounded by factors that might affect these levels and also the incidence of cancer. For example, vitamin A can come from animal or vegetarian sources. Because animal fat has been identified as a potential carcinogen in man, depending on the source of the vitamin, varying levels of protection might be deduced. In addition, chemoprevention studies using dietary supplements are expected to have mild effects, and large studies would be required to confirm statistical significance. Even with agents such as intravesical chemotherapy, only half the studies achieve statistical significance [29]. Prospective randomized trials with a large sample size, longer follow-up, and an extended duration of treatment are needed to clarify the association between micronutrients and cancer protection. With these caveats in mind, several recommendations can be made. Simple measures, such as drinking more fluids (especially water), can have a profound impact on the incidence of bladder cancer. Vitamins are being extensively studied in chemopreventive trials for different cancers. There is strong evidence for a chemoprotective effect of vitamin A in bladder cancer. The authors recommend 32,000 IU/day of vitamin A initially, with lower doses (24,000 IU) for persons less than 50 kg. Because liver toxicity is a possibility with long-term administration, the dose should be decreased to 16,000 IU after 3 years. High doses of beta-carotene should be avoided based on a large clinical trial reporting a 25% increase in the number of cases of prostate cancer and a statistically significant increase in the incidence of lung cancer. Vitamin B6 has been studied in several clinical trials in bladder cancer. The US-based Veterans Administration cooperative study found benefit for vitamin B6 when given as a single agent. Data for vitamins C and E are insufficient to recommend either agent as stand-alone treatment. Nonetheless, each of these vitamins is known to have beneficial effects, including improved function of the immune system. It is possible that only a small percentage of patients with bladder cancer respond to vitamins B6, C, or E, yet each is safe, nontoxic, and inexpensive. In an effort to pool the efficacy of individual agents and to increase the power of study, the authors evaluated the combination of vitamins A, B6, C, and E in a double-blind trial. The observed 50% 5-year reduction in tumor recurrence was highly significant and greater than would be expected for any of the individual ingredients and suggests that combinations of nutritional agents may be most appropriate. A large-volume study along similar lines is being conducted. Among the numerous other compounds and dietary substances purported to have chemopreventive effect, soybeans, garlic, and green tea stand out as having the greatest promise and can freely be recommended to patients. For synthetically synthesized agents such as celecoxib, piroxicam, or DFMO, recommendations must be deferred until the results of clinical trials are conclusively in favor of their use. Many of the dietary factors found to be protective against bladder cancer are being investigated in other cancers and are beneficial to general health. Although naturally occurring nutrients are ideal, especially because the delicate balance of various micronutrients might be impossible to synthesize in the laboratory, the general population finds it easier to take vitamin supplements. Unfortunately, dietary changes such as decreasing fat and increasing fruit and vegetable intake are more difficult to initiate. There is a mistaken notion that simply because an agent is naturally occurring, it cannot be as beneficial as taking a substance synthesized in the laboratory. Even in a high-risk group such as nuclear-bomb survivors in Japan, high consumption of vegetables and fruit is protective against bladder cancer [44]. Encouraging patients to follow an essentially healthy food habit lifestyle will be a significant contribution in the fight against cancer.

Potential lifestyle and dietary supplement options for the prevention and postdiagnosis of bladder cancer

Apart from smoking, certain occupational exposures, and schistosomiasis, little is known about other potential lifestyle risk factors for bladder cancer. Other investigations thus far have also been important because of the large number of individuals who are diagnosed with this cancer that apparently have no known risk factors. Preventing the recurrence of bladder cancer has generated some interest because several preliminary trials have found that a combination dietary supplement of vitamins and minerals or a probiotic agent (Lactobacillus casei) may impact this outcome favorably. Advising patients on some of these lifestyle modifications is currently recommended because the majority of them are also currently recommended for cardiovascular disease reduction.

Foods and nutrients in relation to bladder cancer risk: a case-control study in Aichi Prefecture, Central Japan

To elucidate the role of diet in the etiology of bladder cancer, we conducted a case-control study from 1996 to 1999 in Aichi Prefecture, Central Japan. Cases were patients newly diagnosed with bladder cancer, and one hospital control was selected for each case, matching gender, age, and hospital. A well-validated food frequency questionnaire was adopted to estimate intakes of nutrients and food groups. Odds ratios (ORs) adjusted for smoking and occupational history were computed using conditional logistic models. The analyses based on 297 cases and 295 controls revealed the following. 1) The more the intake of milk and dairy products, the lower the OR; the ORs across quartiles in all subjects were 1.02, 0.73, and 0.52. Fruit intake was negatively associated with the risk, particularly in men (ORs across quartiles = 0.76, 0.77, and 0.52). Green-yellow vegetables were associated with a decreased risk in the highest quartile of consumption in men (OR = 0.57). 2) Dietary intakes of retinol and saturated fatty acids were related to a reduced risk in all subjects (ORs across quartiles = 0.75, 0.54, and 0.66 and 0.55, 0.54, and 0.60, respectively). Monounsaturated fatty acids had an inverse association with bladder cancer risk in men.

Are retinol, vitamin C, vitamin E, folate and carotenoids intake associated with bladder cancer risk? Results from the Netherlands Cohort Study

In the Netherlands Cohort Study among 120 852 subjects aged 55-69 years at baseline (1986), the association between vitamins and carotenoids intake, vitamin supplement use, and bladder cancer incidence was examined. Exposure status was measured with a food-frequency questionnaire. After 6.3 years of follow-up, data from 569 cases and 3123 subcohort members were available for case-cohort analyses. The age-, sex-, and smoking-adjusted relative risks (RRs) for retinol, vitamin E, folate, a-carotene, b-carotene, lutein and zeaxanthin, and lycopene were 1.04, 0.98, 1.03, 0.99, 1.16, 1.11, and 1.08, respectively, comparing highest to lowest quintile of intake. Only vitamin C (RR: 0.81, 95% CI: 0.61-1.07, P-trend = 0.08), and b-cryptoxanthin intake (RR: 0.74, 95% CI: 0.53-1.03, P-trend < 0.01) were inversely associated with bladder cancer risk. The association with vitamin C disappeared after adjustment for b-cryptoxanthin but not vice versa. The RRs for supplemental use of vitamin A, C or E compared to no use were around unity. We conclude that dietary or supplemental intake of vitamin A, vitamin C, vitamin E, and intake of folate, and most carotenoids are not associated with bladder cancer. In this study, only b-cryptoxanthin intake appeared to be inversely associated.