A Pilot Intervention Designed to Increase Cruciferous Vegetable Intake to Reduce Bladder Cancer Recurrence and Progression

Abstract

Study Purpose: Bladder cancer is one of the top 10 most common cancers in the US and is the most expensive cancer to treat. The majority of bladder cancers (70–80%) are diagnosed at early stages as non-muscle invasive bladder cancer (NMIBC), which can be removed surgically. However, 50–80% of NMIBC recurs within 5 years, and 15–30% progresses with poor survival. Current treatment is limited. Preclinical and epidemiologic evidence suggests that dietary isothiocyanates (ITCs) in cruciferous vegetables could be a non-invasive and cost-effective strategy to improve NMIBC prognosis. Thus, the purpose of our study was to develop and pilot test a cruciferous vegetable intervention designed to increase ITC exposure in NMIBC survivors. Methods: We used a blinded 2-arm randomized controlled trial (RCT) to test the preliminary efficacy of a 6-month cruciferous vegetable intervention for NMIBC survivors. The intervention consisted of mailed materials, a live phone-call to review the materials, and 11 Interactive Voice Responses calls. Three-day urine samples, 3-day dietary recalls, and survey data were collected at baseline and 6-months. Two-sided Wilcoxon rank-sum tests were used for between-group comparisons. Results: Forty-nine NMIBC patients diagnosed in 2018–2019 were randomized and 42 (22 treatment, 20 control) were retained for 6-month follow-up. Participants were mostly male (71.4%) and White (90.5%), with an average age of 67.4 years. Compared to the control, the treatment group reported 35.0 g (95% CI: −14.9, 85.0; P = 0.014) higher Cruciferae intake (treatment = 58.6 ± 54.5 g vs. control = 23.6 ± 96.1g) and increased urinary ITC levels by 11.1 μmol/g creatinine (treatment = 14.2 ± 24.5 vs. control = 3.1 ± 13.9, P = 0.027) at 6-month follow-up. Conclusion: Our behavioral cruciferous vegetable intervention is the first to significantly increase cruciferous vegetable intake and ITC levels in NMIBC survivors. Our evidence-based dietary intervention has the potential to offer an affordable, scalable option for NMIBC survivors to reduce their risk of recurrence and improve outcomes.