Fruit and vegetable consumption, dietary and plasma carotenoids and risks of recurrence and progression in patients with non-muscle-invasive bladder cancer
Fruit and vegetable consumption may decrease bladder cancer risk, but research on its relation to outcomes of non-muscle-invasive bladder cancer (NMIBC) is scarce. We investigated the association of (changes in) pre- and postdiagnosis fruit and vegetable consumption, as well as postdiagnosis dietary and plasma carotenoids, with risks of recurrence and progression in patients with NMIBC. Data from patients with newly diagnosed NMIBC between 2014 and 2021 from the prospective multi-centre cohort UroLife was used. Patients reported prediagnosis diet (n = 1396), and diet at 3 and 15 months postdiagnosis (n = 1270). Plasma carotenoid concentrations were measured at 3 and 15 months postdiagnosis (n = 910). Multivariable proportional hazards regression analyses were performed to assess associations with risks of first recurrence, multiple recurrences, and progression. Median follow-up time was 4.7 years, 466 patients had at least one recurrence, 139 had multiple recurrences, and 153 showed progression. Total fruit and vegetable consumption at 3 months postdiagnosis as well as pre-to-postdiagnosis increases in consumption were inversely associated with first recurrence risk (per 100 g/day: hazard ratio [HR] = 0.91, 95% confidence interval ([95%CI] 0.85–0.99 and HR = 0.90, 95%CI 0.81–0.99, respectively). Results were attenuated at 15 months after diagnosis. Total and individual dietary and plasma carotenoids were not associated with first recurrence risk. No associations with multiple recurrences and progression, and for prediagnosis fruit and vegetable consumption were found. Higher postdiagnosis fruit and vegetable consumption may have a beneficial role in NMIBC recurrence but not progression risk while no associations for dietary and plasma carotenoids were found.