NCRI Conference 2017
10 November 2017
This year’s National Cancer Research Institute (NCRI) Conference took place 5 - 8 November 2017 in Liverpool. Amongst the poster presentations was "A randomized controlled feasibility trial of green tea and lycopene interventions in men at elevated risk of prostate cancer (ProDiet)"
Abstract: Prostate specific antigen (PSA) testing identifies some men with elevated PSA levels below biopsy thresholds and others without cancer at biopsy who have an increased risk of prostate cancer. The ProDiet trial aimed to establish the feasibility of dietary modification for lycopene and green tea in these groups which could potentially lower cancer risk.
Men aged 50-69 years were identified through community-based PSA testing in the Prostate cancer testing and Treatment trial with PSA results between 2.0-2.95 ng/ml or negative prostatic biopsies. Participants were randomized, according to a 2x3 factorial design, to daily green tea drink (3 cups, open label) or capsules (blinded, 600 mg flavanols or placebo) and to daily lycopene-rich foods (open label) or capsules (blinded, 15 mg lycopene or placebo) for six months. Primary outcomes were recruitment and intervention adherence (blinded assessment of circulating metabolites) with acceptability, weight, blood pressure and PSA also assessed at six months.
133/469 men invited were randomised and 131 completed follow-up. Mean plasma lycopene levels were 1.25x higher in the lycopene capsule group (p = 0.005) and 1.42x higher in tomato-enriched diet group (p<0.001) compared to placebo. Median plasma flavanol levels were 12.3 nM higher in the flavanol capsule group and 24.9 nM higher in the green tea drink group compared with placebo (both p<0.001). Interventions were acceptable, although some men preferred capsules to dietary changes. No major alterations occurred in clinical outcomes. Most men would consider participating in a longer trial (99/133).
Conclusion: Men adhered successfully to two dietary interventions with elevation of circulating green tea flavanols and lycopene at 6 months. Dietary prevention is acceptable to men at risk of prostate cancer, and a randomized trial is feasible.