Diet and Dietary Supplement Intervention Trials for the Prevention of Prostate Cancer Recurrence: A Review of the Randomized Controlled Trial Evidence

Purpose

We review the effect of diet and dietary supplement interventions on prostate cancer progression, recurrence and survival.

Materials and Methods

A literature search was conducted in MEDLINE^®, EMBASE^® and CINAHL^® to identify diet and dietary supplement intervention studies in men with prostate cancer using prostate specific antigen or prostate specific antigen doubling time as a surrogate serum biomarker of prostate cancer recurrence and/or survival.

Results

Of the 32 studies identified 9 (28%) were randomized controlled trials and the focus of this review. In these studies men had confirmed prostate cancer and elevated or increasing prostate specific antigen. Only 1 trial included men with metastatic disease. When body mass index was reported, men were overweight or obese. A significant decrease in prostate specific antigen was observed in some studies using a low fat vegan diet, soy beverage or lycopene supplement. While not often reported as an end point, a significant increase in prostate specific antigen doubling time was observed in a study on lycopene supplementation. In only 1 randomized controlled trial in men undergoing orchiectomy was a survival end point of fewer deaths with lycopene supplementation reported.

Conclusions

A limited number of randomized controlled trials were identified in which diet and dietary supplement interventions appeared to slow disease progression in men with prostate cancer, although results vary. Studies were limited by reliance on the surrogate biomarker prostate specific antigen, sample size and study duration. Well designed trials are warranted to expand knowledge, replicate findings and further assess the impact of diet and dietary supplement interventions on recurrence and treatment associated morbidities.

Key Words: diet, dietary supplements, prostatic neoplasms, recurrence

Abbreviations and Acronyms: BMI, body mass index, HRPC, hormone refractory prostate cancer, PSA, prostate specific antigen, PSADT, prostate specific antigen doubling time, RCT, randomized, controlled trial