UCSF

Purpose

Diet after prostate cancer diagnosis may impact disease progression. We hypothesized that consuming saturated fat after prostate cancer diagnosis would increase risk of mortality, and consuming vegetable fat after diagnosis would lower the risk of mortality.

Methods

This was a prospective study among 926 men with non-metastatic prostate cancer in the Physicians' Health Study who completed a food frequency questionnaire a median of 5 years after diagnosis and were followed for a median of 10 years after the questionnaire. We examined post-diagnostic saturated, monounsaturated, polyunsaturated, and trans fat, as well as animal and vegetable fat, intake in relation to all-cause and prostate cancer-specific mortality. Hazard ratios (HR) and 95 % confidence intervals (CI) were estimated using multivariate Cox proportional hazards regression.

Results

We observed 333 deaths (56 prostate cancer deaths) during follow-up. Men who obtained 5 % more of their daily calories from saturated fat and 5 % less of their daily calories from carbohydrate after diagnosis had a 1.8-fold increased risk of all-cause mortality (HR 1.81; 95 % CI 1.20, 2.74; p value 0.005) and a 2.8-fold increased risk of prostate cancer-specific mortality (HR 2.78; 95 % CI 1.01, 7.64; p value 0.05). Men who obtained 10 % more of their daily calories from vegetable fats and 10 % less of their daily calories from carbohydrates had a 33 % lower risk of all-cause mortality (HR 0.67; 95 % CI 0.47, 0.96; p value 0.03).

Conclusions

Among men with non-metastatic prostate cancer, saturated fat intake may increase risk of death and vegetable fat intake may lower risk of death.