Coffee is known to contain a variety of bioactive compounds and plant-derived antioxidants that help to reduce systemic inflammation. As a result, coffee may slow the progression of solid tumours, and its consumption has been linked to lower colorectal cancer recurrence rates and mortality. A higher coffee consumption has also been linked to a lower risk of prostate cancer, but few studies have examined associations between coffee consumption and survival after prostate cancer diagnosis.
The single-nucleotide variant (SNV; *1F allele) 163A>C (rs762551) indicates cytochrome P450 1A2 enzyme activity (CYP1A2). It is used to classify caffeine metabolizers as fast or slow. Against this backdrop, Justin R. Gregg, Department of Urology, Division of Surgery, University of Texas, Houston, TX, USA, and colleagues investigated the relationship between coffee consumption, rs762551 genotype, and survival. They used a large consortium database of prostate cancer cases that had been followed for death from prostate cancer and other causes.
The researchers hypothesised that a higher coffee intake would be associated with prostate cancer-specific survival, particularly in men who metabolise caffeine quickly. The researchers used data from the PRACTICAL Consortium database for 5727 men with prostate cancer from seven studies in Australia, the United States, and Europe for this purpose. The cases included data for the CYP1A2 163C>A rs762551 single-nucleotide variant associated with coffee consumption, caffeine metabolism, and more than 6 months of follow-up.
The effect of coffee consumption (classified as low [reference], high, or none/very low) was compared across pooled patient-level data on prostate cancer-specific survival and overall survival using multivariable-adjusted Cox proportional hazards models (OS). According to the findings of the study, high coffee consumption appeared to be associated with longer PCSS (hazard ratio [HR] 0.85) and overall survival (HR 0.90), though the results were not statistically significant.
High coffee consumption was associated with a longer PCSS (HR 0.66) in the group with clinically localised disease, with comparable results in the group with advanced disease (HR 0.92). High coffee consumption was associated with longer PCSS among men with the CYP1A2 AA genotype (HR 0.67) but not the AC/CC genotype; an interaction was found. Subgroup analyses revealed no associations with OS. The nominal statistical significance and residual confounding are two limitations. "Coffee consumption was associated with a longer prostate cancer-specific survival among men with a CYP1A2 163AA (*1F/*1F) genotype," the researchers wrote. "More research is required to fully understand which men may benefit and why."
Gregg JR, Kim J, Logothetis C, Hanash S, Zhang X, Manyam G, Muir K; UKGPCS Collaborative Group, Giles GG, Stanford JL, Berndt SI, Kogevinas M, Brenner H, Eeles RA; PRACTICAL Consortium, Wei P, Daniel CR; PRACTICAL Consortium, Wei P, Daniel CR; PRACTICAL Consortium, Wei P, Daniel CR Coffee Consumption, Caffeine Metabolism Genotype, and Prostate Cancer Survival in Men S2588-9311(22)00138-9, Eur Urol Oncol, 2022 Aug 19. doi: 10.1016/j.euo.2022.07.008. Epub before print. PMID: 35995710.