Colon to Rectum
Am J Gastroenterol. 2022;117(6):884–94
Green tea extract to prevent colorectal adenomas, results of a randomized, placebo-controlled clinical trial
Introduction: Preclinical, epidemiological, and small clinical studies suggest that green tea extract (GTE) and its major active component epigallocatechingallate (EGCG) exhibit antineoplastic effects in the colorectum.
Methods: A randomized, double-blind trial of GTE standardized to 150 mg of EGCG b.i.d. versus placebo over 3 years was conducted to prevent colorectal adenomas (n = 1001 with colon adenomas enrolled, 40 German centers). Randomization (1:1, n = 879) was performed after a 4-week run-in with GTE for safety assessment. The primary end point was the presence of adenoma/colorectal cancer at the follow-up colonoscopy 3 years after randomization.
Results: The safety profile of GTE was favorable with no major differences in adverse events between the 2 well-balanced groups. Adenoma rate in the modified intention-to-treat (ITT) set (all randomized participants [ITT population] and a follow-up colonoscopy 26–44 months after randomization; n = 632) was 55.7% in the placebo group and 51.1% in the GTE group. This 4.6% difference was not statistically significant (adjusted relative risk [aRR] = 0.905; p = 0.1613). The respective figures for the per-protocol population were 54.3% (151/278) in the placebo group and 48.3% (129/267) in the GTE group, indicating a slightly lower adenoma rate in the GTE group, which was not significant (aRR = 0.883; p = 0.1169).
Discussion: Green tea extract (GTE) was well tolerated, but there was no statistically significant difference in the adenoma rate between the GTE and the placebo groups in the whole study population.