Can green tea extract prevent colorectal adenoma recurrence?

Use of green tea extract (GTE) is well tolerated but does not appear to prevent colorectal adenomas, results of a recent trial have shown.

A team of investigators carried out a randomized, double-blind trial of GTE standardized to 150 mg of epigallocatechingallate (EGCG) twice a day compared with placebo over 3 years to prevent recurrence in patients with colon adenomas at 40 German centres. A total of 879 patients were randomized 1:1 after a 4-week run-in with GTE for safety assessment.

The presence of adenoma/colorectal cancer (CRC) at follow-up colonoscopy 3 years after randomization was the primary endpoint.

GTE was found safe, with no major differences in adverse events between the GTE and placebo groups. Adenoma rate in the modified intention-to-treat population was 51.1 percent in the GTE group and 55.7 percent in the placebo group. The 4.6-percent difference was not statistically significant (adjusted relative risk, 0.905; p=0.1613).

In the per-protocol population, the adenoma rate was 54.3 percent (151/278) in the placebo group and 48.3 percent (129/267) in the GTE group. This suggested a slightly lower adenoma rate in the GTE arm, which was statistically nonsignificant (adjusted relative risk, 0.883; p=0.1169).

“GTE/EGCG intake over 3 years was safe but had no significant effect on colorectal adenoma recurrence in the whole population of a nationwide CRC screening program,” the investigators said.