Objectives: We examined post-diagnostic diet and risk of cancer progression in a cohort of men with prostate cancer from the Health Professionals Follow-up Study.
Methods: We observed 392 progression outcomes among 1,202 men diagnosed with incident localized/regional prostate cancer between 1986 and 1996. Men completed prospective dietary surveys before and after diagnosis and were followed through 2000. We examined post-diagnostic consumption of red meat, grains, vegetables, fruits, milk, tomatoes, tomato sauce, and fish as predictors of progression using Cox proportional hazard regression models adjusted for total energy, age, clinical factors, and pre-diagnostic diet.
Results: Men in the highest versus lowest quartile of post-diagnostic fish consumption had a multivariate hazard ratio (HR) of progression of 0.73 (95% CI 0.52-1.02); the comparable HR for tomato sauce was 0.56 (95% CI 0.38-0.82). We observed inverse linear relationships for fish and tomato sauce and risk of progression (HR = 0.83, p-value = 0.006 and HR = 0.80, p-value = 0.04 for a two serving/week increase of fish and tomato sauce, respectively). Milk and fresh tomato consumption were associated with small elevations in risk.
Conclusions: These data suggest that diet after diagnosis may influence the clinical course of prostate cancer, and fish and tomato sauce may offer some protection against disease progression.