Antioxidant Supplement and Reduction of Metachronous Adenomas of the Large Bowel: a Double Blind Randomized Trial

Study Overview
=================
Brief Summary
-----------------
The trial was aimed at evaluating the efficacy of a multiagent antioxidant compound (vitamin A, C, E, selenium and zinc) in reducing the incidence of metachronous adenomas of the large bowel after endoscopic polypectomy. This is a randomized study: a 50% reduction in the incidence of metachronous adenomas was expected in patients allocated to the active compound (intervention) arm as compared to those assigned to a placebo.

Detailed Description
-----------------
Adenomatous polyps (or adenoma) are benign lesions of the large bowel that are frequent in people aged 60 or more: about one in four of them has at least one adenoma. In time, adenoma could progress to cancer. Even though only a small rate of adenomas will develop into cancer almost 70-80% of colorectal cancer origin from an adenoma and colorectal cancer is one of the most frequent malignant tumors in the western world. Several epidemiological studies showed that subjects who had low intake and/or low blood levels of selenium were at increased risk of developing colorectal cancer.

Official Title
-----------------
Evaluation of the Efficacy of a Combination of Micronutrients (Vitamin A, C, E, Selenium and Zinc) in Reducing the Incidence of Colorectal Metachronous Adenomas. A Double Blind, Phase III, Randomized, Placebo-controlled Trial

Conditions
-----------------
Colorectal Adenomas

Intervention / Treatment
-----------------
* Drug: antioxidants
* Drug: placebo


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: age 25-75 years at least one histologically confirmed adenoma endoscopically removed from the large bowel resulting in a polyp-free colon-rectum (clean colon). Exclusion Criteria: polypectomy performed more than 6 months before enrolment in the trial history of Familial Adenomatous Polyposis inflammatory bowel disease adenoma with invasive carcinoma ten or more adenomas large sessile adenoma (3 cm or more colorectal resection invasive cancer at any site life-threatening and/or chronic heart, liver or kidney diseases current use of vitamin or calcium supplements mental disability

Ages Eligible for Study
-----------------
Minimum Age: 25 Years
Maximum Age: 75 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: antioxidants<br>tablets composed of 200 mcg selenium [as l-selenomethionine], 30 mg zinc, 2 mg vitamin A [retinol], 180 mg vitamin C [ascorbic acid] and 30 mg vitamin E [D-α-tocopherol acetate] | Drug: antioxidants<br>* tablets composed of 200 mcg selenium [as l-selenomethionine], 30 mg zinc, 2 mg vitamin A [retinol], 180 mg vitamin C [ascorbic acid] and 30 mg vitamin E [D-α-tocopherol acetate]<br>* Other names: Bio-selenium, Pharma Nord (DK);|
| Placebo Comparator: Sugar pill<br>placebo had an identical appearance as intervention | Drug: placebo<br>* placebo had an identical appearance as intervention<br>* Other names: placebo was provided by Pharma Nord;|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| occurrence of metachronous adenomas or cancer detected during endoscopic follow up examinations |  | five years | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
chemoprevention, colorectal cancer, metachronous adenoma, randomized trial