A prospective study of lycopene and tomato product intake and risk of prostate cancer

Background: Dietary lycopene and tomato products may reduce risk of prostate cancer; however, uncertainty remains about this possible association. Methods: We evaluated the association between intake of lycopene and specific tomato products and prostate cancer risk in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, a multicenter study designed to investigate cancer early detection methods and etiologic determinants. Participants completed both a general risk factor and a 137-item food frequency questionnaire at baseline. A total of 1,338 cases of prostate cancer were identified among 29,361 men during an average of 4.2 years of follow-up. Results: Lycopene intake was not associated with prostate cancer risk. Reduced risks were also not found for total tomato servings or for most tomato-based foods. Statistically nonsignificant inverse associations were noted for pizza [all prostate cancer: relative risk (RR), 0.83; 95% confidence interval (95% CI), 0.67-1.03 for >= 1 serving/wk versus < 0.5 serving/mo; P-trend = 0.06 and advanced prostate cancer: RR, 0.79; 95% CI, 0.56-1.10; P-trend = 0.12] and spaghetti/tomato sauce consumption (advanced prostate cancer: RR = 0.81, 95% Cl, 0.57-1.16 for >= 2 servings/wk versus < 1 serving/mo; P-trend = 0.31). Among men with a family history of prostate cancer, risks were decreased in relation to increased consumption of lycopene (P-trend = 0.04) and specific tomato-based foods commonly eaten with fat (spaghetti, P-trend = 0.12; pizza, P-trend = 0.15; lasagna, P-trend = 0.02). Conclusions: This large study does not support the hypothesis that greater lycopene/tomato product consumption protects from prostate cancer. Evidence for protective associations in subjects with a family history of prostate cancer requires further corroboration.