Higher Dietary Lycopene Intake Associated With Reduced Risk of Lethal Prostate Cancer and Reduced Tumor Angiogenesis
In a study reported in the Journal of the National Cancer Institute, Zu et al found that higher dietary lycopene intake was associated with reduced risk of lethal prostate cancer and reduced tumor angiogenesis. Lycopene-rich foods include tomatoes and tomato-based products.
Study Details
The study involved analysis of dietary information from questionnaires and ascertainment of total and lethal prostate cancers among 49,898 male health professionals from the Health Professionals Follow-up Study from 1986 through January 2010. Tissue microarrays and immunohistochemistry were used to analyze tumor biomarker expression in a subset of men.
Men in the upper quintiles of lycopene intake were slightly younger, more likely to engage in vigorous physical activity, consumed less alcohol, coffee, and fats and slightly more fruits, vegetables, and dietary fiber. Intake of lycopene was positively correlated with consumption of tomato and tomato products, including tomato juice, tomato sauce, and pizza.
Increased Intake and Risk
In multivariate analysis adjusting for age, height, body mass index, race, family history of prostate cancer, vigorous activity, smoking status, and dietary intake of calcium, alpha-linolenic acid, coffee, and total calories, increased lycopene intake was associated with reduced risk for total prostate cancer (hazard ratio [HR] = 0.91, 95% confidence interval [CI] = 0.84–1.00, for highest vs lowest quintile; P = .009 for trend) and reduced risk for lethal prostate cancer (HR = 0.72, 95% CI = 0.56–0.94, P = .04 for trend).
In the time period before widespread use of prostate-specific antigen screening (before 1994), hazard ratios were 0.85 (95% CI = 0.72–1.00, P = .07 for trend) for total prostate cancer and 0.72 (95% CI = 0.51–1.00, P = .07 for trend) for lethal cancer. In the prostate-specific antigen era, hazard ratios were 0.95 (95% CI = 0.86-1.10, P = .05 for trend) for total cancer and 0.72 (95% CI = 0.49–1.10, P = .10 for trend) for lethal cancer.
Risk in Screened Population
When multivariate analysis was restricted to men with at least one negative prostate-specific antigen test to further adjust for effects of prostate-specific antigen screening, increased intake was associated with significantly reduced risk of total prostate cancer (HR = 0.88, 95% CI = 0.79–0.98, P = .02 for trend) and lethal cancer (HR = 0.47, 95% CI = 0.29–0.75, P = .009 for trend). The risk reductions for total cancer (HR = 0.86, P = .004 for trend) and lethal cancer (HR = 0.48, P = .009 for trend) were significant in analysis by baseline intake, but not in analysis by updated intake (HR = 0.92, P = .09 for trend, and HR = 0.66, P = .06 for trend).
In analysis of updated lycopene intake, higher lycopene intake was associated with tumor biomarkers indicative of less angiogenic potential—ie, better vessel diameter, vessel area, irregularity of vessel lumen, and angiogenic score in all tumors (P < .001 for trend for all) and in organ-confined tumors (P ≤ .01 for trend for all).
The investigators concluded, “Dietary intake of lycopene was associated with reduced risk of lethal prostate cancer and with a lesser degree of angiogenesis in the tumor. Because angiogenesis is a strong progression factor, an endpoint of lethal prostate cancer may be more relevant than an endpoint of indolent prostate cancer for lycopene in the era of highly prevalent prostate-specific antigen screening.”
Edward Giovannucci, MD, ScD, of Harvard School of Public Health, is the corresponding author for the Journal of the National Cancer Institute article.
The study was funded by grants from the National Institutes of Health.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
