Plant-based diets help lower risk of prostate cancer progression

Men with prostate cancer who consume higher amounts of plant-based foods have a lower risk of cancer progression, as shown in a longitudinal observational cohort study.

The study included 2,062 men (median age 65.0 years, 95 percent White) with biopsy-proven nonmetastatic prostate cancer (stage ≤T3a). All men completed a comprehensive diet and lifestyle questionnaire (including a validated food frequency questionnaire [FFQ]). The median time from prostate cancer diagnosis to FFQ completion was 31.3 months.

Data from the FFQ were used to calculate overall plant-based diet index (PDI) and healthful plant-based diet index (hPDI) scores. Prostate cancer progression (recurrence, secondary treatment, bone metastases, or prostate cancer–specific mortality) was the primary outcome, and prostate cancer–specific mortality was the secondary outcome.

Over a median follow-up of 6.5 years, 190 progression events and 61 prostate cancer–specific mortality events were recorded. The risk of progression was 47-percent lower among men scoring in the highest versus lowest quintile of PDI (hazard ratio [HR], 0.53, 95 percent confidence interval [CI], 0.37–0.74; p=0.003 for trend).

There was no association between hPDI scores and the risk of progression overall. However, in the subset of 680 men with Gleason grade 7 or higher at diagnosis, those scoring in the highest versus lowest hPDI quintile had a 55-percent lower risk of progression (HR, 0.45, 95 percent CI, 0.25–0.81; p=0.01 for trend).

The findings highlight the potential of nutritional assessment and counselling for patients with prostate cancer in helping establish healthy dietary practices and support wellbeing and overall health.