e13559 Background: The popular beverage tea, brewed from infused leaves of camellia sinesis, contains non-phytoestrogenic polyphenols such as flavonoids, anthocyanidins, flavanols (epigallocatechin gallate); phenolic acids (ellagic acid) and stimulants (caffeine, theophylline). Laboratory studies report tea promotes antioxidant enzyme formation, slows cancer cell proliferation and unblocks apoptosis. Clinically, the Pomi-T randomised study reported tea extract (along with three other foods) reduced PSA progression in men with prostate cancer1. Evidence of prostate cancer prevention, however, from prospective cohort data is conflicting with one recent study even implying an increased risk2. Methods: We analysed 25,097 men within the intervention arm of the 155,000 participant PLCO screening trial. Histological confirmed cases of prostate cancer were reported in 3,088 men (12.3%) during the 11.5 year follow up. Tea consumption was assessed with a food frequency questionnaire (FFQ). Baseline characteristics were compared between groups using Chi-square and Kruskal-Wallis tests. Cox regression models were used to assess the association between tea intake and prostate cancer incidence. Results: Overall tea consumption was associated with a significantly lower risk of prostate cancer (p = 0.009). More precisely, the participants in the highest third of consumption group had a significantly lower risk compared to those in the lowest third (HR 1.16 (CI 1.05-1.29, p = 0.004). This pattern persisted with adjustments for age, sex, race and education level (p = 0.034), family history of cancer (p = 0.037). Those who never drank tea, however, had no statistical lower risk of prostate cancer compared to other groups (p = 0.501). Conclusions: Among tea drinkers, this data revealed a positive association between drinking tea and a reduced risk of prostate cancer. This data supports the consideration of future prospective intervention studies investigating the role of tea as part of a prostate cancer prevention programme. 1. Thomas et al. The NCRN Pomi-T RCT. Prostate cancer & prostatic diseases (2014), 2,180. 2. Reger et al. Dietary isoflavones and prostate cancer risk. Int J. Cancer (2017), 142; 4, 719.
Dietary consumption of tea and the risk of prostate cancer in the prostate, lung, colorectal, and ovarian cancer screening trial.
