Dietary modification in patients with prostate cancer on active surveillance: a randomized, multicentre feasibility study

OBJECTIVES: To evaluate the feasibility of implementing a diet-based intervention in men with prostate cancer on active surveillance, as changes in diet might potentially inhibit the progression of prostate cancer. PATIENTS AND METHODS: As part of the Men’s Eating and Living (MEAL) Study (a multicentre pilot trial of a diet-based intervention for prostate cancer) 43 men aged 50-80 years with prostate cancer and on active surveillance were randomized to receive either telephone-based dietary counselling or standardized, written nutritional information. Telephone counselling targets included increased intakes of vegetables (particularly cruciferous vegetables and tomato products), whole grains, and beans/legumes. Dietary intakes and plasma carotenoid levels were assessed at baseline and at after 6 months. RESULTS: In the intervention arm the mean daily intakes of total vegetables, crucifers and tomato products increased by 71%, 180% and 265%, respectively (P < 0.05); in the control arm there were no significant changes in mean intakes of these components. Similarly, in the intervention arm, mean plasma levels of alpha-carotene, beta-carotene, lutein, lycopene and total carotenoids increased by 37%, 32%, 23%, 30% and 25%, respectively (P < 0.05); in the control arm there were no significant changes in plasma levels of these components. There were no significant changes in either group in whole grain, beans/legumes, or fat intake. CONCLUSIONS: Telephone-based dietary counselling increases vegetable intake and plasma concentrations of potentially anticarcinogenic carotenoids in men with prostate cancer on active surveillance. These data support the feasibility of implementing clinical trials of diet-based interventions in this population.