Body Mass Index, Diet-Related Factors, and Bladder Cancer Prognosis: A Systematic Review and Meta-Analysis

Abstract

Background:Urologists are frequently confronted with questions of urinary bladder cancer (UBC) patients about what they can do to improve their prognosis. Unfortunately, it is largely unknown which lifestyle factors can influence prognosis.Objective:To systematically review the available evidence on the association between body mass index (BMI), diet, dietary supplements, and physical activity and UBC prognosis.Methods:We searched PubMed and Embase up to May 2017. We included thirty-one articles reporting on observational and randomized controlled trials investigating BMI, diet and dietary supplements in relation to recurrence, progression, cancer-specific or all-cause mortality in UBC patients.Results:In non-muscle invasive bladder cancer (NMIBC) patients, both overweight (3 studies, pooled hazard ratio (HR) 1.29, 95% CI 1.05–1.58, I2 = 0%) as well as obesity (3 studies, pooled HR 1.82, 95% CI 1.12–2.95, I2 = 79%) were associated with increased risk of recurrence when compared to normal weight. No association of BMI with risk of progression was found. Results for BMI and prognosis in muscle-invasive or in all stages series were inconsistent. Observational studies on diet and randomized controlled trials with dietary supplements showed inconsistent results. No studies on physical activity and UBC prognosis have been published to date.Conclusions:Evidence for an association of lifestyle factors with UBC prognosis is limited, with some evidence for an association of BMI with risk of recurrence in NMIBC. Well-designed, prospective studies are needed to develop evidence-based guidelines on this topic.

Modifiable lifestyle behaviours impact the health‐related quality of life of bladder cancer survivors

“…This is in contrast to reports from other cancer sites, which have reported that being overweight or obese may result in functional decline and reduced HRQoL . Despite this finding, there is emerging evidence to suggest an association between BMI and cancer recurrence, and counselling regarding weight loss is recommended .…”

No clear associations of adult BMI and diabetes mellitus with non-muscle invasive bladder cancer recurrence and progression

“…Although obesity and DM seem to be associated with UBC risk, only few studies are published on their associations with risk of tumour recurrence or progression in NMIBC patients. In a recent meta-analysis based on three historical cohort studies, our group found a pooled hazard ratio (HR) of 1.82 (95% CI: 1.12-2.95) for recurrence and 1.90 (95% CI: 0.93-3.88) for progression in obese versus healthy weight NMIBC patients [9,[19][20][21]. Hwang et al (2011) found increased risks of recurrence and progression for diabetic compared with non-diabetic NMIBC patients [22].…”

“…These tables focus mainly on primary tumour characteristics. However, lifestyle factors such as smoking and obesity, as well as diabetes mellitus (DM), may also be relevant in the prognosis of NMIBC [9], and may contribute to more personalized follow-up schedules.…”

Lifestyle and Non-muscle Invasive Bladder Cancer Recurrence, Progression, and Mortality: Available Research and Future Directions

“…Eighteen studies have assessed the association between body mass index (BMI) and prognosis [7,24,25,30,34,39,59,[65][66][67][68][69][70][71][72][73][74][75]. One study assessed BMI at diagnosis, [24] 13 studies assessed BMI at time of treatment (e.g., transurethral resection of bladder tumor (TURBT), radical cystectomy), [25,30,34,39,59,[65][66][67][68][69][70][71][72] and three studies did not report timing of BMI measurement [73][74][75].…”