This is a randomized, placebo controlled, multicentric trial to investigate the effect of diet supplementation with green tea extract containing 300mg epigallocatechin gallate (EGCG), the major polyphenol of green tea, on the recurrence of colon adenomas.

Prevention of colorectal cancer is a major health care issue because of the high incidence of this cancer. So far, pharmaceutical chemoprevention has not gained widespread acceptance due to side effects of the chemopreventive agents used. Nutraceuticals such as polyphenols from tea plants have demonstrated remarkable therapeutic and preventive effects in molecular, epidemiological and clinical trials. However, controlled trials demonstrating the efficacy of nutraceuticals fo the prevention of colorectal cancer are largely missing.

The investigators present this randomized, placebo controlled, multicentric trial to investigate the effect of diet supplementation with green tea extract containing 300mg epigallocatechin gallate (EGCG), the major polyphenol of green tea, on the recurrence of colon adenomas.

Patients who underwent polypectomy for colonic polyps will be randomized after a one month verum run-in period to receive either 150mg EGCG two times daily or placebo over the course of three years. The beneficial safety profile of decaffeinated green tea extract, the quantifiable and known active content EGCG, and the accumulating evidence on its cancer preventive potential require in our view a validation of this compound for the "nutriprevention" of colorectal adenoma. Good accessibility and low costs might render this nutraceutical a top candidate for a wider use as food supplement in colon cancer prevention.

Inclusion Criteria:

• Between 50-80 years of age
• Histologically confirmed colorectal adenomas or serrated lesions removed during colonoscopy within the last 6 months
• Good performance status (ECOG < 2) at study entrance
• Written informed consent.

Exclusion Criteria:

• History of hereditary nonpolyposis colorectal cancer (HNPCC) or familial adenomatous polyposis (FAP)
• History of colon or rectal cancer, other concomitant cancers with the exemption of basalioma or curative treated cancers without actual anticancer medication.
• Intestinal malabsorption, short bowel syndrome or surgical bowel interventions leading to malabsorption
• Liver failure (hepatitis, cirrhosis, elevation of liver enzymes ALT, AST or bilirubin to more than 2.5 fold of the reference levels)
• Inflammatory bowel disease
• Regular intake of NSAIDs (also Cox2 inhibitors) for more than 3 months per year except of low-dose aspirin (100 mg per day)
• Immunosuppressive medication
• Impaired capacity to consent or who are impaired in swallowing a pill
• Regular consumption of green tea extract as nutritional supplement (with a content of EGCG of more than 100mg per day) of longer than 6 months during the past two years
• Allergic reactions towards green tea