Active surveillance (AS) is increasingly used as a management strategy for localized prostate cancer. Coffee intake has been associated with lower prostate cancer incidence; and we assessed whether coffee was associated with disease progression in men on AS.

Patients with newly diagnosed Gleason score (GS) 6 or 7 prostate cancer were enrolled on a prospective AS protocol for at least 6 months and completed a baseline dietary assessment (n=411). The AS protocol included a biennial monitoring regimen with disease progression defined as an increase in GS. Cox proportional hazards models were used to evaluate associations of coffee intake with progression-free survival. Patient genotype in the caffeine metabolism-related SNP rs762551 was also evaluated.

Median follow-up was 36 months (range 6 - 126), and 76/411 (18.5%) had GS progression. In the multivariable model adjusting for PSA, age and tumor length, compared to 0 cups/day, <1 cup (HR 0.85, 95%CI 0.40-1.71), 1-1.9 cups (HR 0.64, 95%CI 0.29-1.43), 2-3.9 cups (HR 0.71, 95%CI 0.35-1.47), and ≥4 cups (HR 1.67, 95%CI 0.81-3.45) were not significantly associated with progression-free survival (P for non-linearity = 0.01). Patients with low/moderate coffee intake and the AA "fast caffeine metabolizer" genotype were less likely to experience grade progression, as compared to non-consumers (HR 0.36, 95% CI 0.15-0.88, P=0.03).

Low to moderate coffee intake appears safe in men on AS for localized prostate cancer. Further work is needed to determine if high consumption is associated with shorter progression-free survival in sensitive groups.