Lycopene, tomato products and prostate cancer-specific mortality among men diagnosed with nonmetastatic prostate cancer in the Cancer Prevention Study II Nutrition Cohort.

Abstract

While dietary lycopene and tomato products have been inversely associated with prostate cancer incidence, there is limited evidence for an association between consumption of lycopene and tomato products and prostate-cancer specific mortality (PCSM). We examined the associations of prediagnosis and postdiagnosis dietary lycopene and tomato product intake with PCSM in a large prospective cohort. This analysis included men diagnosed with nonmetastatic prostate cancer between enrollment in the Cancer Prevention Study II Nutrition Cohort in 1992 or 1993 and June 2011. Prediagnosis dietary data, collected at baseline, were available for 8,898 men, of whom 526 died of prostate cancer through 2012. Postdiagnosis dietary data, collected on follow-up surveys in 1999 and/or 2003, were available for 5,643 men, of whom 363 died of prostate cancer through 2012. Cox proportional hazards regression was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for PCSM. Neither prediagnosis nor postdiagnosis dietary lycopene intake was associated with PCSM (fourth vs. first quartile HR = 1.00, 95% CI 0.78-1.28; HR = 1.22, 95% CI 0.91-1.64, respectively). Similarly, neither prediagnosis nor postdiagnosis consumption of tomato products was associated with PCSM. Among men with high-risk cancers (T3-T4 or Gleason score 8-10, or nodal involvement), consistently reporting lycopene intake ≥ median on both postdiagnosis surveys was associated with lower PCSM (HR = 0.41, 95% CI 0.17-0.99, based on ten PCSM cases consistently ≥ median intake) compared to consistently reporting intake < median. Future studies are needed to confirm the potential inverse association of consistently high lycopene intake with PCSM among men with high-risk prostate cancers.