Purpose: Active surveillance is increasingly used as a management strategy for localized prostate cancer. Coffee intake has been associated with a lower prostate cancer incidence. We assessed whether coffee was associated with disease progression in men on active surveillance.
Materials and methods: A total of 411 patients with newly diagnosed Gleason score 6 or 7 prostate cancer were enrolled on a prospective active surveillance protocol for at least 6 months and completed a baseline dietary assessment. The active surveillance protocol included a biennial monitoring regimen with disease progression defined as an increase in the Gleason score. Cox proportional hazards models were used to evaluate associations of coffee intake with progression-free survival. We also evaluated patient genotype in the caffeine metabolism related single nucleotide polymorphism rs762551.
Results: Median followup was 36 months (range 6 to 126) and the Gleason score progressed in 76 of the 411 patients (18.5%). Compared to 0 cups per day, in the multivariable model adjusting for prostate specific antigen, patient age and tumor length, less than 1 cup (HR 0.85, 95% CI 0.40-1.71), 1 to 1.9 cups (HR 0.64, 95% CI 0.29-1.43), 2 to 3.9 cups (HR 0.71, 95% CI 0.35-1.47) and 4 cups or more (HR 1.67, 95% CI 0.81-3.45) were not significantly associated with progression-free survival (p for nonlinearity = 0.01). Patients with low/moderate coffee intake and the AA fast caffeine metabolizer genotype were less likely to experience grade progression than nonconsumers (HR 0.36, 95% CI 0.15-0.88, p = 0.03).
Conclusions: Low to moderate coffee intake appears safe in men on active surveillance of localized prostate cancer. Further work is needed to determine whether high consumption is associated with shorter progression-free survival in sensitive groups.