Selenium for Prevention of Adenomatous Colorectal Polyps

You may be eligible if

• DISEASE CHARACTERISTICS:
• Histologically confirmed colorectal adenomatous polyps
• Meets the following criteria by colonoscopy (performed within the past 6 months):
• * Cecum was totally visualized or reached
• * At least 90% visualization of colon surface area
• * Removed at least 1 adenomatous polyp of at least 3 mm in size during procedure (For the Advanced Adenoma Sub-study: Removal of at least 1 advanced colorectal adenomatous polyp during procedure. An adenoma is considered advanced if it is 10 mm or greater in size, and/or has villous histology and/or shows high grade dysplasia)
• * Removed no more than 10 adenomatous polyps of any size by endoscopy
• * All other neoplastic and non-neoplastic colon polyps must have been completely removed (except for diminutive \[less than 3 mm\] sessile rectal polyps)
• * For the sub-study, at least 1 advanced adenomatous polyp defined as 10 mm or greater in size and/or has villous histology and/or shows high grade dysplasia
• No prior diagnosis of any of the following:
• * Colorectal cancer
• * Familial adenomatous polyposis
• * Ulcerative colitis
• * Crohn's disease
• * Hereditary non-polyposis colon cancer (HNPCC), defined as:
• * Histologically confirmed colorectal cancer in at least 3 relatives, 1 of whom is a first-degree relative of the other 2
• * Disease occurrence in at least 2 consecutive generations
• * Colorectal cancer diagnosis in at least 1 family member who is less than 50 years of age
• * Patients with a family history of colorectal cancer but who are not diagnosed with HNPCC are allowed
• No more than 1 prior segmental colon resection
• PATIENT CHARACTERISTICS:
• Age
• 40 to 80
• Performance status
• SWOG 0-1
• Life expectancy
• Not specified
• Hematopoietic
• Hemoglobin \> 11 g/dL
• WBC 3,000 - 11,000/mm\^3
• Hepatic
• AST and ALT \< 2 times upper limit of normal
• Bilirubin \< 2.0 mg/dL
• Renal
• Creatinine \< 1.9 mg/dL
• Cardiovascular
• No unstable\* cardiac disease despite medication (e.g., diuretics or digitalis)
• No uncontrolled hypertension (i.e., systolic blood pressure ≥ 170 mm Hg and/or diastolic blood pressure ≥ 110 mm Hg) despite medication NOTE: \*Unstable defined as unable to walk across the room without chest pain or shortness of breath
• Other
• Not pregnant or nursing
• Fertile patients must use effective contraception for at least 2 months before and during study treatment
• Resident of a clinical center metropolitan area or obtaining regular health care in a clinical metropolitan area for at least 6 months out of the year
• Must be able to swallow pills
• No unexpected weight loss of 10% or more within the past 6 months
• No prior rheumatoid arthritis
• No poorly controlled diabetes mellitus despite medication, defined as:
• * Blood sugar level ≥ 200 mg/dL on more than half of the readings taken within the past month
• No invasive malignancy within the past 5 years that required medical excision, radiotherapy, or chemotherapy except basal cell or squamous cell carcinoma
• PRIOR CONCURRENT THERAPY:
• Biologic therapy
• No concurrent drugs that regulate the immune system
• Chemotherapy
• No concurrent chemotherapy
• Endocrine therapy
• Not specified
• Radiotherapy
• No concurrent radiotherapy
• Surgery
• See Disease Characteristics
• Other
• Prior enrollment in another adenoma prevention study allowed
• Concurrent routine aspirin (≤ 81 mg/day) allowed
• No regular use of non-steroidal anti-inflammatory drugs (NSAIDs)
• No concurrent enrollment in another research study using pharmacological cancer drugs, a cyclo-oxygenase-2 inhibitor, or selenium
• No other concurrent selenium unless dosage is ≤ 50 µg/day