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

IRCCS Azienda Ospedaliera Universitaria San Martino - IST Istituto Nazionale per la Ricerca sul Cancro, Genoa, Italy

Status and phase: Terminated; Phase 3

Conditions: Colorectal Adenomas

Treatments: Drug: placebo; Drug: antioxidants

Study type: Interventional

Funder types: Other

Identifiers

NCT01437826

IST-1988

Details and patient eligibility

About

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.

Full 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.

Enrollment: 411 patients

Sex: All

Ages: 25 to 75 years old

Volunteers: No Healthy Volunteers

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

Trial design

Primary purpose: Prevention

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Double Blind

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411 participants in 2 patient groups, including a placebo group

antioxidants

Experimental group

Description:

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 \[D-α-tocopherol acetate\]

Treatment:

Drug: antioxidants

Sugar pill

Placebo Comparator group

Description:

placebo had an identical appearance as intervention

Treatment:

Drug: placebo