Examining the co-occurrence of bladder and prostate cancer: a worthwhile investigation?

Risk of bladder cancer in patients with diabetes: a retrospective cohort study

OBJECTIVE

The objective of this study was to examine the association between diabetes, and both urinary bladder cancer (UBC) risk and mortality.

METHODS

We conducted a retrospective cohort study using data from the UK Clinical Practice Research Datalink (CPRD) linked to the Office of National Statistics (ONS). Patients diagnosed with diabetes mellitus type 1 or 2, or using antidiabetic drugs (ADDs), were compared to matched non-diabetic controls. Cox proportional hazards models were used to estimate the risk and mortality of UBC. We adjusted for age, sex, smoking status and body mass index.

RESULTS

The cohort included 329,168 patients using ADD, and 307,315 controls with 1295 and 1071 patients, respectively, diagnosed as having UBC during follow-up. The adjusted HRs of UBC were 0.77 (95% CI 0.57 to 1.05) and 1.04 (95% CI 0.96 to 1.14) for type 1 and 2 diabetes, respectively. These results were similar if we restricted our analysis to an inception cohort. We noticed a small increased risk during the first year after diagnosis (HR=1.26 (95% CI 1.05 to 1.52)), which could be explained by detection bias. There was no influence of the severity of diabetes as measured by the glycated haemoglobin. Mortality of UBC was not increased for patients with either type 1 (HR=0.95 (95% CI 0.39 to 2.34)) or type 2 diabetes (HR=1.16 (95% CI 0.91 to 1.46)).

CONCLUSIONS

Neither the risk of UBC nor the mortality from UBC was increased in patients with type 1 and patients with type 2 diabetes in the CPRD data.

Designing the selenium and bladder cancer trial (SELEBLAT), a phase lll randomized chemoprevention study with selenium on recurrence of bladder cancer in Belgium

Background

In Belgium, bladder cancer is the fifth most common cancer in males (5.2%) and the sixth most frequent cause of death from cancer in males (3.8%). Previous epidemiological studies have consistently reported that selenium concentrations were inversely associated with the risk of bladder cancer. This suggests that selenium may also be suitable for chemoprevention of recurrence.

Method

The SELEBLAT study opened in September 2009 and is still recruiting all patients with non-invasive transitional cell carcinoma of the bladder on TURB operation in 15 Belgian hospitals. Recruitment progress can be monitored live at http://www.seleblat.org. Patients are randomly assigned to selenium yeast (200 μg/day) supplementation for 3 years or matching placebo, in addition to standard care. The objective is to determine the effect of selenium on the recurrence of bladder cancer. Randomization is stratified by treatment centre. A computerized algorithm randomly assigns the patients to a treatment arm. All study personnel and participants are blinded to treatment assignment for the duration of the study.

Design

The SELEnium and BLAdder cancer Trial (SELEBLAT) is a phase III randomized, placebo-controlled, academic, double-blind superior trial.

Discussion

This is the first report on a selenium randomized trial in bladder cancer patients.

Trial registration

ClinicalTrials.gov identifier: NCT00729287