Associations of dietary isothiocyanate exposure from cruciferous vegetable consumption with recurrence and progression of non-muscle-invasive bladder cancer: findings from the Be-Well Study.
Level 3 - non-randomized controlled study
Prospective cohort study evaluating dietary/biomarker exposures and clinical outcomes without randomization.
PubMed 37044209 · doi:10.1016/j.ajcnut.2023.04.006
What was done
The Be-Well study analyzed 1,143 participants newly diagnosed with non-muscle-invasive bladder cancer (NMIBC) between 2015 and 2019 without prior bladder cancer history. Dietary isothiocyanate (ITC) exposure at diagnosis was assessed via self-reported cruciferous vegetable (CV) intake, estimated ITC intake, urinary metabolites, and plasma ITC-albumin adducts. Over a mean follow-up of 25 months, associations with recurrence and progression were evaluated using Cox proportional hazards regression and logistic regression.
What was found
Recurrence occurred in 347 participants (30%) and progression in 77 (6.7%). Overall recurrence risk was not significantly associated with ITC exposure. However, urinary ITC metabolites (OR: 1.96; 95% CI: 1.01, 4.43) and dietary ITC intake (OR: 2.13; 95% CI: 1.03, 4.50) were associated with late recurrence (after 12 months vs. before 12 months). Raw CV intake was associated with lower odds of multiple recurrences (≥2 vs. 1: OR: 0.34; 95% CI: 0.16, 0.68). Higher plasma concentrations of ITC-albumin adducts were associated with reduced risk of progression, including progression to muscle-invasive disease (benzyl ITC HR: 0.40; 95% CI: 0.17, 0.93; phenethyl ITC HR: 0.40; 95% CI: 0.19, 0.86).
Why it matters
This study provides prospective evidence linking circulating biomarkers of cruciferous vegetable intake to a reduced risk of non-muscle-invasive bladder cancer progression. It suggests that dietary isothiocyanate exposure may have prognostic value in bladder cancer management.
Limits
The observational design cannot establish causality and is subject to residual confounding. Follow-up was relatively short (mean 25 months) with few progression events (n = 77), and dietary exposure was measured only around diagnosis without accounting for subsequent dietary changes.
Cited by
- context Epidemiological studies show that dietary intake of cruciferous vegetables, such as broccoli, is associated with a reduced risk of bladder cancer and bladder cancer recurrence.