Evidence Explorer · MS-N293 · Nutrition and dietary patterns · Appraised November 10, 2026
A six-month randomized behavioral intervention increased cruciferous-vegetable intake and urinary isothiocyanate exposure. The trial did not test whether this prevented bladder-cancer recurrence or progression.
Evidence at a glance
- Population: 49 survivors of non-muscle-invasive bladder cancer were randomized; 42 were retained at six months.
- Intervention: counseling and automated calls targeting one cup of cruciferous vegetables per day versus a general fruit-and-vegetable intervention.
- Primary result: urinary isothiocyanates increased by 11.1 μmol/g creatinine versus control (P=.027). Reported cruciferous intake was 0.94 cups/day higher (95% CI 0.24–1.65).
- Cancer outcome: recurrence, progression and disease-specific survival were not trial endpoints.
- Evidence label: successful dietary-behavior and exposure intervention; cancer-control benefit unproven.
- Evidence label: Diet and biomarker change; recurrence untested.
What was studied
The POW-R Health program used mailed materials, a live review call and eleven interactive voice-response calls. It showed that a targeted food intervention can change both reported intake and a urinary exposure biomarker.
The authors linked the biomarker target to laboratory and observational research. Those sources generate a hypothesis; they do not convert the biomarker result into proof that the intervention prevents recurrence.
What this evidence cannot establish
The trial was small, seven randomized participants were not retained, intake was partly self-reported, and the comparator also promoted fruits and vegetables. It was not powered or followed long enough for recurrence, progression or survival.
Safety and practical context
Cruciferous vegetables are foods, not substitutes for cystoscopy, intravesical therapy or other surveillance and treatment. Concentrated isothiocyanate products are different from food. People with swallowing difficulty, restricted potassium intake, warfarin management or significant gastrointestinal symptoms should individualize intake with their care team.
Questions for the care team
- What cancer outcome would a future trial need to measure before making a recurrence claim?
- Am I using food or a concentrated supplement with different exposure and safety?
- How does this fit with standard bladder surveillance and treatment?
Sources and identifiers
- Randomized POW-R Health trial — PMID 38408431
- Open full text — PMCID PMC11325219
Funding and conflicts: Supported by National Cancer Institute awards R21 CA253910-01 and P30 CA016056. The authors reported no financial consideration supporting preparation, analysis or discussion of the article.
Source access and dates: Primary reports, registries and official guidance available through the links above were checked November 10, 2026. Last literature search November 10, 2026. Fields unavailable from accessible full text are labeled not reported or not verified rather than assumed absent.
Educational evidence summary, not individualized medical advice. Restrictive diets or supplements should not replace established cancer treatment or adequate nutrition. Symptom, weight, biomarker, laboratory, imaging, pathology or animal findings do not by themselves establish tumor control, recurrence prevention or longer survival.
