Selenium and Vitamin E for Prevention of Non-Muscle-Invasive Bladder Cancer Recurrence and Progression: A Randomized Clinical Trial.

Importance: Selenium and vitamin E have been identified as promising agents for the chemoprevention of recurrence and progression of non-muscle-invasive bladder cancer. Objective: To determine whether selenium and/or vitamin E may prevent disease recurrence in patients with newly diagnosed NMIBC. Design, Setting, and Participants: This multicenter, prospective, double-blinded, placebo-controlled, 2 × 2 factorial randomized clinical trial included patients with newly diagnosed NMIBC recruited from 10 secondary or tertiary care hospitals in the UK. A total of 755 patients were screened for inclusion; 484 did not meet the inclusion criteria, and 1 declined to participate. A total of 270 patients were randomly assigned to 4 groups (selenium plus placebo, vitamin E plus placebo, selenium plus vitamin E, and placebo plus placebo) in a double-blind fashion between July 17, 2007, and October 10, 2011. Eligibility included initial diagnosis of NMIBC (stages Ta, T1, or Tis); randomization within 12 months of first transurethral resection was required. Interventions: Oral selenium (200 µg/d of high-selenium yeast) and matched vitamin E placebo, vitamin E (200 IU/d of d-alfa-tocopherol) and matched selenium placebo, selenium and vitamin E, or placebo and placebo. Main Outcome and Measures: Recurrence-free interval (RFI) on an intention-to-treat basis (analyses completed on November 28, 2022). Results: The study randomized 270 patients (mean [SD] age, 68.9 [10.4] years; median [IQR] age, 69 [63-77] years; 202 male [75%]), with 65 receiving selenium and vitamin E placebo, 71 receiving vitamin E and selenium placebo, 69 receiving selenium and vitamin E, and 65 receiving both placebos. Median overall follow-up was 5.5 years (IQR, 5.1-6.1 years); 228 patients (84%) were followed up for more than 5 years. Median treatment duration was 1.5 years (IQR, 0.9-2.5 years). The study was halted because of slow accrual. For selenium (n = 134) vs no selenium (n = 136), there was no difference in RFI (hazard ratio, 0.92; 95% CI, 0.65-1.31; P = .65). For vitamin E (n = 140) vs no vitamin E (n = 130), there was a statistically significant detriment to RFI (hazard ratio, 1.46; 95% CI, 1.02-2.09; P = .04). No significant differences were observed for progression-free interval or overall survival time with either supplement. Results were unchanged after Cox proportional hazards regression modeling to adjust for known prognostic factors. In total, 1957 adverse events were reported; 85 were serious adverse events, and all were considered unrelated to trial treatment. Conclusions and Relevance: In this randomized clinical trial of selenium and vitamin E, selenium supplementation did not reduce the risk of recurrence in patients with NMIBC, but vitamin E supplementation was associated with an increased risk of recurrence. Neither selenium nor vitamin E influenced progression or overall survival. Vitamin E supplementation may be harmful to patients with NMIBC, and elucidation of the underlying biology is required. Trial Registration: isrctn.org Identifier: ISRCTN13889738.

Relationship between Bladder Cancer, Nutritional Supply, and Treatment Strategies: A Comprehensive Review.

Bladder cancer (BC) is the predominant neoplasm affecting the urinary system and ranks among the most widespread malignancies globally. The causes of bladder cancer include genetic factors; age; sex; and lifestyle factors, such as imbalanced nutrition, obesity, and metabolic disorders. The lack of proper nutrient intake leads to the development of bladder cancer because insufficient nutrients are consumed to prevent this disease. The purpose of this review was to analyze the nutrients closely linked to the onset and advancement of bladder cancer and to explore the relationship between dietary nutrients and bladder cancer. Particular emphasis was placed on nutrients that are frequently ingested in daily life, including sugar, fat, protein, and others. The focus of this research was to analyze how nutritional intake before and after surgery affects the recovery process of patients who have been diagnosed with bladder cancer. This article seeks to increase awareness among both society and the medical community about the significance of implementing appropriate dietary nutrition to reduce the chances of developing bladder cancer, enhance perioperative care for patients with bladder cancer, and aid in their recuperation.

Dietary vitamin D intake and the bladder cancer risk: A pooled analysis of prospective cohort studies.

BACKGROUND & AIMS: Diet may play an essential role in the aetiology of bladder cancer (BC). Vitamin D is involved in various biological functions which have the potential to prevent BC development. Besides, vitamin D also influences the uptake of calcium and phosphorus, thereby possibly indirectly influencing the risk of BC. The aim of the present study was to investigate the relation between vitamin D intake and BC risk. METHODS: Individual dietary data were pooled from ten cohort studies. Food item intake was converted to daily intakes of vitamin D, calcium and phosphorus. Pooled multivariate hazard ratios (HRs), with corresponding 95% confidence intervals (CIs) were obtained using Cox-regression models. Analyses were adjusted for gender, age and smoking status (Model 1), and additionally for the food groups fruit, vegetables and meat (Model 2). Dose-response relationships (Model 1) were examined using a nonparametric test for trend. RESULTS: In total, 1994 cases and 518,002 non-cases were included in the analyses. The present study showed no significant associations between individual nutrient intake and BC risk. A significant decreased BC risk was observed for high vitamin D intake with moderate calcium and low phosphorus intake (Model 2: HRhigh vitD, mod Ca, low P: 0.77, 95% CI: 0.59-1.00). No significant dose-response analyses were observed. CONCLUSION: The present study showed a decreased BC risk for high dietary vitamin D intake in combination with low calcium intake and moderate phosphorus intake. The study highlights the importance of examining the effect of a nutrient in combination with complementary nutrients for risk assessment. Future research should focus on nutrients in a wider context and in nutritional patterns.

Fatty foods and the risk of bladder cancer: A case-control study.

OBJECTIVE: The aim of this study was to explore the association between dietary fatty foods and the risk for bladder cancer. METHODS: Patients newly diagnosed with bladder cancer (n = 113) and 292 controls were recruited. A food frequency questionnaire (FFQ) was used to investigate the food intake within 1 y. Multivariate logistic regression model was used to estimated odds ratio (OR) between different types of fatty food consumption and bladder cancer. RESULTS: The consumption of soybean oil, the largest proportion of cooking oil, in both groups were much higher than the Chinese recommended dietary intake, especially in the control group. Higher intake of red meat was also observed in bladder cancer cases, although lower intakes of marine fish, egg, milk, and dairy products and nuts were observed in controls. After adjusting for potential confounders, the intakes of marine fish and milk and dairy products were negatively correlated with bladder cancer, with the adjusted OR of 0.28 (95% confidence interval [CI], 0.15-0.55) and 0.36 (95% CI, 0.19-0.69). Total nuts were related to a 76% reduction in bladder cancer risk (OR, 0.24; 95% CI, 0.12-0.48). There was clear and positive association between soybean oil and bladder cancer risk with OR of 3.47 (95 % CI, 1.69-7.14). In stratified analyses by sex and smoking status, the relationship was similar for most results, except for milk and dairy products. The negative correlation between milk and dairy products and bladder cancer risk was only found in men; and milk and dairy products and bladder cancer risk were irrelevant by smoking status. No significant association was found between the intakes of other foods and bladder cancer risk. CONCLUSIONS: Intake of nuts and marine fish may be beneficial for the prevention of bladder cancer. The protective effect of milk and dairy products was only found in men with bladder cancer. High soybean oil intake was a risk factor for bladder cancer.

Omega-3 polyunsaturated fatty acids: a modified approach for chemo-prevention of bladder cancer in a rat model and molecular studies of antineoplastic mechanisms.

OBJECTIVES: To test the chemo-preventative effects of omega-3 against bladder cancer (BC) induction in a rat model and its potential antineoplastic mechanisms. MATERIAL AND METHODS: Ninety male Fisher rats were divided into three groups during a 22-week protocol: group 1 (control), group 2 (Placebo + N-butyl-N-4- hydroxybutyl nitrosamine (BBN) for induction of BC and group 3 received omega-3 (1200 mg/kg/day) + BBN. At the end, blood samples and bladder tissues were collected and checked for the presence of malignancy, markers of angiogenesis (VEGF relative gene expression), inflammation (IL-6), proliferation (KI-67 expressions), oxidative stress (serum MDA and serum SOD) and epigenetic control (miRNA-145 level). RESULTS: At the end of the study, 60% and 86.6% rats survived in group 2 and 3 with significant weight loss among rats in group 2 when compared with other groups. In group 2, all rats developed visible bladder lesions of which five and 13 developed squamous cell carcinoma (SCC) and transitional cell carcinoma (TCC). In omega3-treated group, only one developed low grade SCC and one developed high grade non- invasive TCC. Bladders from omega-3-treated rats showed lower expression ofKI-67 (p < 0.05), VEGF (p < 0.001) and IL-6 (p < 0.001) and significant higher expression of mi-RNA (p < 0.001). Also, omega-3-treated group showed statistically significant lower MDA level (p < 0.001). CONCLUSION: Omega-3 inhibits bladder tumor growth in the BBN-induced BC rat model, due to anti-inflammatory, antioxidant, anti-proliferative, and anti-angiogenic properties together with epigenetic control.

Clinical Potential of Fruit in Bladder Cancer Prevention and Treatment.

Bladder cancer (BC) is the most common tumor of the urinary system in the world. Moreover, despite using anticancer therapies, BC is also characterized by a high recurrence risk. Among numerous risk factors, cigarette smoking, occupational exposure to certain aromatic compounds, and genetic factors contribute most strongly to BC development. However, the epidemiological data to date suggests that diet quality may influence some carcinogenic factors of BC and, therefore, might have a preventative effect. Adequate consumption of selected fruits with scientifically proven properties, including pomegranates and cranberries, can significantly reduce the risk of developing BC, even in those at risk. Therefore, in this article, we aim to elucidate, using available literature, the role of fruits, including pomegranates, cranberries, citrus fruits, cactus pears, and apples, in BC prevention and treatment. Previous data indicate the role of compounds in the above-mentioned fruits in the modulation of the signaling pathways, including cell proliferation, cell growth, cell survival, and cell death.

Transurethral resection in women with symptomatic keratinizing squamous metaplasia of urinary bladder: A retrospective study of 92 cases.

OBJECTIVES: To investigate the efficacy of transurethral resection (TUR) on relieving urinary symptoms in patients with keratinizing squamous metaplasia (KSM) of the urinary bladder. METHODS: Data were analyzed from a retrospective study of patients receiving transurethral bipolar plasma resection (bi-TUR) treatment for symptomatic KSM. Urinary symptoms were assessed by the International Prostate Symptom Score (IPSS) and a numeric rating scale pain score. Efficacy was assessed using the IPSS to determine changes from baseline in lower urinary tract symptoms (LUTS). Self-reported quality of life (QoL) was assessed by the last question of the IPSS questionnaire. RESULTS: A total of 92 female patients were included in the analysis. The median age was 42 years. LUTS, pain, and hematuria were the most common symptoms that affected patients. The median follow-up duration was 51 months. There were significant improvements in LUTS from baseline IPSS after TUR (P < .001). The percentage of the patients with moderate to severe LUTS went down from 52.2% to 18.5%. The median Numeric Rating Scale (NRS)-11 pain score reduced from 3 at baseline to 0 at the last visit. Twenty-one out of 40 patients reported that the pain symptoms disappeared completely. No patients reported hematuria symptoms at the final follow-up. Improvement of self-reported QoL was significant (P < .001). A total of 57.6% of patients reported an improvement, 26.1% of patients reported no improvement, and 16.3% reported deterioration. CONCLUSIONS: Bi-TUR therapy significantly relieved urinary symptoms in women with KSM. Improvement of QoL was acceptable with a success rate of 57.6%. Considering the very low complication rate, our study supported bi-TUR as an alternative treatment for patients who are resistant to medical therapy.

Lifestyle and nutritional modifiable factors in the prevention and treatment of bladder cancer.

Bladder cancer is one of the top 5 most common cancers diagnosed in the U.S. It is also one of the most expensive cancers to treat through the life course given its high rate of recurrence. While cigarette smoking and occupational exposures have been firmly established as risk factors, it is less certain whether modifiable lifestyle factors such as diet and physical activity play roles in bladder cancer etiology and prognosis. This literature review based on a PubMed search summarizes the research to date on key dietary factors, types of physical activity, and smoking in relation to bladder cancer incidence, and discusses the potential public health implications for formalized smoking cessation programs among recently diagnosed patients. Overall, population-based research in bladder cancer is growing, and will be a key platform to inform patients diagnosed and living with bladder cancer, as well as their treating clinicians, how lifestyle changes can lead to the best outcomes possible.

Bladder Cancer Chemopreventive Agents: Current Knowledge and Concepts.

Bladder cancer is the most prevalent malignancy of the urinary tract and is associated with significant morbidity and mortality. Preventative efforts to reduce the medical and financial burdens of bladder cancer are highly desirable. However, the utilization of natural and pharmaceutical products for the prevention and treatment of bladder cancer remains largely controversial. Herein, we review the current body of evidence surrounding a number of natural dietary substances and their roles in chemoprevention of bladder cancer. Possible chemopreventative properties of several pharmaceutical agents are also reviewed. Overall, the current body of evidence is insufficient to establish a clear link between these proposed chemopreventive agents and risk of bladder cancer.

Clinical Proteomics for Precision Medicine: The Bladder Cancer Case.

Precision medicine can improve patient management by guiding therapeutic decision based on molecular characteristics. The concept has been extensively addressed through the application of -omics-based approaches. Proteomics attract high interest, as proteins reflect a "real-time" dynamic molecular phenotype. Focusing on proteomics applications for personalized medicine, a literature search was conducted to cover: a) disease prevention, b) monitoring/ prediction of treatment response, c) stratification to guide intervention, and d) identification of drug targets. The review indicates the potential of proteomics for personalized medicine by also highlighting multiple challenges to be addressed prior to actual implementation. In oncology, particularly bladder cancer, application of precision medicine appears especially promising. The high heterogeneity and recurrence rates together with the limited treatment options, suggest that earlier and more efficient intervention, continuous monitoring, and the development of alternative therapies could be accomplished by applying proteomics-guided personalized approaches. This notion is backed by studies presenting biomarkers that are of value in patient stratification and prognosis, and by recent studies demonstrating the identification of promising therapeutic targets. Herein, we aim to present an approach whereby combining the knowledge on biomarkers and therapeutic targets in bladder cancer could serve as basis towards proteomics-guided personalized patient management.

Prevention of bladder cancer incidence and recurrence: nutrition and lifestyle.

PURPOSE OF REVIEW: We review the influence of nutrition and lifestyle on bladder cancer incidence and recurrence and summarize food items, diets and lifestyle practices that physicians may wish to prioritize for discussion with their patients. RECENT FINDINGS: Recent study results suggest an association between bladder cancer incidence and several food items including meat, fruit, vegetables, milk products and oil. Micronutrient deficiency is associated with bladder cancer risk; however, it remains unclear if micronutrient supplementation can modify bladder cancer incidence. Furthermore, total fluid intake, alcohol, coffee and tea seem to have no influence on bladder cancer incidence. There is weak evidence that stress, anxiety and lack of sleep may increase the risk of developing bladder cancer, whereas exercise may reduce the risk of dying from it. SUMMARY: Several dietary items and life styles are associated with bladder cancer incidence and recurrence. However, besides smoking cessation, there is no evidence that a certain diet or lifestyle can decrease bladder cancer incidence.

Effectivity of intravescical thermo-chemotherapy prophylaxis for patients with high recurrence and progression risk for non-muscle invasive bladder cancer.

Background&Aim: High grade non-muscle invasive bladder cancer (NMIBC) is common in urological practice. Most of these cancers are or become refractory to intravesical immunotherapy and chemotherapy. Here we evaluated the efficacy of combined local bladder hyperthermia and intravesical mitomycin-C (MMC) instillation in patients with high-risk recurrent NMIBC. MATERIALS AND METHODS: Between February 2014 and December 2015, 18 patients with high risk NMIBC were enrolled. Patients were treated in an outpatient basis with 6 weekly induction sessions followed by monthly maintenance sessions with intravesical MMC in local hyperthermia with bladder wall thermo-chemotherapy (BWT) system (PelvixTT system, Elmedical Ltd., Hod Hasharon, Israel). The follow-up regimen included cystoscopy after the induction cycle and thereafter with regular intervals. Time to disease recurrence was defined as time from the first intravesical treatment to endoscopic or histological documentation of a new bladder tumour. Adverse events were recorded according to CTC 4.0 (Common Toxicity Criteria) score system. RESULTS: Mean age was 72 (32-87) years. 10 patients had multifocal disease, 9 had CIS, 6 had recurrent disease and 2 had highly recurrent disease (> 3 recurrences in a 24 months period). 6 patients underwent previous intravesical chemotherapy with MMC. The average number of maintenance sessions per patient was 7.6. After a mean follow-up of 433 days, 15 patients (83.3%) were recurrence-free. 3 patients had tumour recurrence after a mean period of 248 days without progression. Side effects were limited to grade 1 in 2 patients and grade 2 in 1 patient. CONCLUSIONS: BWT seems to be feasible and safe in high grade NMIBC. More studies are needed to identify the subgroup of patients who may benefit more from this treatment.

Garlic extract in bladder cancer prevention: Evidence from T24 bladder cancer cell xenograft model, tissue microarray, and gene network analysis.

There is a growing interest in the use of naturally occurring agents in cancer prevention. This study investigated the garlic extract affects in bladder cancer (BC) prevention. The effect of garlic extract in cancer prevention was evaluated using the T24 BC BALB/C-nude mouse xenograft model. Microarray analysis of tissues was performed to identify differences in gene expression between garlic extract intake and control diet, and gene network analysis was performed to assess candidate mechanisms of action. Furthermore, we investigated the expression value of selected genes in the data of 165 BC patients. Compared to the control group, significant differences in tumor volume and tumor weight were observed in the groups fed 20 mg/kg (p<0.05), 200 mg/kg, and 1000 mg/kg of garlic extract (p<0.01). Genes (645) were identified as cancer prevention-related genes (fold change >2 and p<0.05) by tissue microarray analysis. A gene network analysis of 279 of these genes (p<0.01) was performed using Cytoscape/ClueGo software: 36 genes and 37 gene ontologies were mapped to gene networks. Protein kinase A (PKA) signaling pathway including AKAP12, RDX, and RAB13 genes were identified as potential mechanisms for the activity of garlic extract in cancer prevention. In BC patients, AKAP12 and RDX were decreased but, RAB13 was increased. Oral garlic extract has strong cancer prevention activity in vivo and an acceptable safety profile. PKA signaling process, especially increasing AKAP12 and RDX and decreasing RAB13, are candidate pathways that may mediate this prevention effect.

Effects of Vitamin and Antioxidant Supplements in Prevention of Bladder Cancer: a Meta-Analysis of Randomized Controlled Trials.

This study aimed to investigate the effects of vitamin and antioxidant supplements in the prevention of bladder cancer using a meta-analysis of randomized controlled trials (RCTs). Fourteen RCTs were included in the final analysis. In a fixed-effect meta-analysis, vitamin and antioxidant supplements showed no preventive effect for bladder cancer (relative risk [RR] = 1.04; 95% confidence interval [CI] 0.92-1.17; I² = 39.7%). Also, there was no preventive effect of these supplements in the subgroup meta-analyses by various factors such as type of supplements, type of cancer prevention, methodological quality, providers of supplements, type of control group, and number of participants. Among the subgroup analyses by type of supplements, beta-carotene supplementation alone marginally increased the risk of bladder cancer (RR = 1.44; 95% CI 1.00-2.09; I² = 0.0%; n = 3). The current meta-analysis found that vitamin and antioxidant supplements have no preventive effect against bladder cancer.

Preventive effect of intravesical ozone supplementation on n-methyl-n-nitrosourea-induced non-muscle invasive bladder cancer in male rats.

Although non-muscle invasive bladder cancer (NMIBC) is widely seen in men, most laboratory studies of new intravesical therapies to prevent NMIBC have been conducted on female animals. In addition, ozone (O3) has been shown to be a beneficial agent as an intravesical application in the treatment of various disorders. In the current study, we evaluated the immunohistopathological and oxidative-antioxidative effects of intravesical O3 treatment on n-methyl-n-nitrosourea (MNU)-induced NMIBC. Male Wistar-Albino rats (n=51) were divided into four groups: sham (n=6), O3 only (n=15), MNU only (n=15), and MNU+O3 (n=15). The MNU-only and MNU+O3 groups received MNU, and the O3-only group received saline every other week for 10 weeks. The MNU-only group received 1 ml saline in place of O3 treatment, whereas the O3-only and MNU+O3 groups were treated with 1 ml 25 µg/ml O3 between the 7th and 12th weeks. Rat bladders were collected in the 15th week for immunohistopathology and oxidant-antioxidant quantitation. Oxidant-antioxidant parameters were determined by ELISA. Although all surviving rats in the MNU-only group had preneoplastic (4/11, 36.4%) or neoplastic changes (7/11, 63.6%), a completely normal urothelium was observed in 2 rats (2/12, 16.7%) in the MNU+O3-group (P=0.478). More high-grade lesions were observed in the MNU-only group (4/11, 36.4%) than in the MNU+O3 group (1/12, 8.3%) (P=0.120). All oxidant-antioxidant parameters significantly increased (P<0.05) in the O3-only group compared with the sham group. However, only antioxidant superoxide dismutase was remarkably higher (178.9%, P=0.060) in the MNU+O3 group compared with the MNU-only group. This is the first methodologically and pathologically well-described male rat orthotopic bladder carcinogenesis model with intravesical MNU and administration of O3 in NMIBC.

Chemopreventive effect of omega-3 polyunsaturated fatty acids and atorvastatin in rats with bladder cancer.

Bladder cancer remains a huge concern for the medical community because of its incidence and prevalence rates, as well as high percentage of recurrence and progression. Omega-3 polyunsaturated fatty acids and atorvastatin proved anti-inflammatory effects through peroxisome proliferator-activated receptor gamma mechanism. However, their chemopreventive effect still remained to be examined and clarified. In this study, bladder cancer was induced in rats by the chemical carcinogen N-butyl-N-(4-hydroxybutyl)nitrosamine. Omega-3 polyunsaturated fatty acids (docosahexaenoic acid and eicosapentaenoic acid: 2:3 w/w; 1200 mg/kg) and/or atorvastatin (6 mg/kg) were given orally daily to rats for eight consecutive weeks concomitantly with N-butyl-N-(4-hydroxybutyl)nitrosamine and continued for further 4 weeks after cessation of N-butyl-N-(4-hydroxybutyl)nitrosamine administration. The histopathological examination of rat bladder revealed the presence of tumors and the absence of apoptotic bodies in sections from N-butyl-N-(4-hydroxybutyl)nitrosamine group, while tumors were absent and apoptotic bodies were clearly observed in sections from rat groups treated with omega-3 polyunsaturated fatty acids, atorvastatin, or both drugs. The study of the molecular mechanisms illustrated downregulation of COX-2 and P53 (mutant) genes and suppression of transforming growth factor beta-1 and the lipid peroxidation product malondialdehyde in serum of rats of the three treated groups. This chemopreventive effect was confirmed by and associated with lower level of bladder tumor antigen in urine. However, the combined treatment with both drugs exhibited the major protective effect and nearly corrected the dyslipidemia that has been induced by N-butyl-N-(4-hydroxybutyl)nitrosamine. Collectively, omega-3 polyunsaturated fatty acids and atorvastatin, besides having anti-inflammatory properties, proved a chemopreventive effect against bladder cancer, which nominates them to be used as adjuvant therapy with other chemotherapeutics.

The association between coffee consumption and bladder cancer incidence in a pooled analysis of the Miyagi Cohort Study and Ohsaki Cohort Study.

Recent epidemiological studies of the association between coffee consumption and the risk of bladder cancer have yielded conflicting results. The aim of the present study was to examine the association between coffee consumption and the incidence of bladder cancer on the basis of pooled data from two cohort studies carried out in Miyagi Prefecture, northeastern Japan. We delivered self-administered questionnaires inquiring about the frequency of coffee consumption and other lifestyle factors in 1990 for the Miyagi Cohort Study and in 1994 for the Ohsaki Cohort Study. We followed 73 346 individuals from both cohorts and identified 274 cases of bladder cancer during 17.6 years for the Miyagi Cohort Study and 13.3 years for the Ohsaki Cohort Study. The multivariate-adjusted hazard ratios (95% confidence intervals) of bladder cancer incidence for the individuals who drank coffee occasionally, 1-2 cups/day, and 3 or more cups/day compared with never drinkers were 1.22 (0.90-1.66), 0.88 (0.61-1.26), and 0.56 (0.32-0.99), respectively (Ptrend=0.04). The inverse association remained even after stratification for smoking status. These data indicate that there is a significant inverse association between coffee consumption and the risk of bladder cancer.

Dietary factors associated with bladder cancer.

It is biologically plausible for dietary factors to influence bladder cancer risk considering that beneficial as well as harmful components of a diet are excreted through the urinary tract and in direct contact with the epithelium of the bladder. However, studies that investigated the association between dietary factors and bladder cancer (BC) risk have largely reported inconsistent results. The macronutrient intake and risk of BC could have yield inconsistent results across studies because of lack of details on the type, source and the quantities of different dietary fatty acids consumed. There is evidence to suggest that consumption of processed meat may increase BC risk. Dietary carbohydrate intake does not appear to be directly associated with BC risk. Even though a large number of studies have investigated the association between fruit/vegetable consumption/micronutrients in those and BC risk, they have yielded inconsistent results. Gender-specific subgroup analysis, details of how fruits and vegetables are consumed (raw vs. cooked), adequate control for smoking status/aggressiveness of the cancer and consideration of genetic make-up may clarify these inconsistent results. There is no strong evidence to suggest that supplementation with any common micronutrient is effective in reducing BC risk. These limitations in published research however do not totally eclipse the observation that a diet rich in fruits and vegetables and low in processed meat along with especially smoking cessation may convey some protective effects against BC risk.

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.