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Selenium for Prevention of Adenomatous Colorectal Polyps

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
ClinicalTrials.gov Identifier: NCT00078897
Recruitment Status : Terminated (Concluded - Terminated by PI)
First Posted : March 9, 2004
Results First Posted : September 24, 2019
Last Update Posted : September 24, 2019
National Cancer Institute (NCI)
Information provided by (Responsible Party):
University of Arizona

Brief Summary:

RATIONALE: Chemoprevention therapy is the use of certain drugs to try to prevent the development or recurrence of cancer. Selenium may be effective in preventing the recurrence of adenomatous colorectal polyps.

PURPOSE: This randomized phase III trial is studying selenium to see how well it works in preventing the recurrence of polyps in patients with adenomatous colorectal polyps.

Condition or disease Intervention/treatment Phase
Colorectal Cancer Adenomatous Colorectal Polyps Precancerous Condition Drug: Selenium Phase 3

Detailed Description:



  • Compare the effects of selenium vs placebo on the recurrence of adenomatous colorectal polyps, in terms of histologic type, degree of dysplasia, number, size, and location, in patients with adenomatous colorectal polyps.
  • Compare the type, incidence, and outcome of side effects in patients treated with these regimens.
  • Determine patient adherence to long-term treatment with these regimens.


  • Determine the effects of regimen modification by baseline blood selenium level, low-dose aspirin, selenoprotein genetic marker polymorphisms (e.g., GPx-1, GPx-2, and SEP15)
  • Determine the effects of low-dose aspirin (81 mg/day) modification by ornithine decarboxylase promoter genotype, and toxicity by slow-metabolizer genotypes of the cytochrome p450 2C9 and UT1A6 loci in these patients.

OUTLINE: This is a randomized, double-blind, placebo-controlled, multicenter study. Patients are stratified according to use of low-dose (≤ 81 mg/day) aspirin (yes vs no). Patients are randomized to 1 of 2 treatment arms.

  • Arm I: Patients receive oral selenium once daily.
  • Arm II: Patients receive oral placebo once daily. In both arms, treatment continues for up to 5 years* in the absence of disease progression or unacceptable toxicity.

Patients undergo follow-up colonoscopy approximately 5 years* after baseline colonoscopy.

NOTE: Some patients will continue participation for up to 7 and a half years

PROJECTED ACCRUAL: A total of 1,600 patients with an adenoma will be randomized to this study, followed by a second group of randomization of 200 patients with at least one advanced adenoma (at baseline) for a substudy. Total planned randomizations = 1,800 participants.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 1621 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Prevention
Official Title: Phase III Study of the Effects of Selenium on Adenomatous Polyp Recurrence
Actual Study Start Date : January 20, 2005
Actual Primary Completion Date : January 7, 2014
Actual Study Completion Date : May 17, 2018

Arm Intervention/treatment
Active Comparator: Selenium
Participants receive oral selenium 200 mcg once daily.
Drug: Selenium
Participants will be randomized either to selenium or placebo, taking the randomized intervention for 3 to 5 years, depending on when their recommended follow up colonoscopy is scheduled.
Other Name: SelenoExcell

Placebo Comparator: Placebo
Participants receive oral placebo once daily.
Drug: Selenium
Participants will be randomized either to selenium or placebo, taking the randomized intervention for 3 to 5 years, depending on when their recommended follow up colonoscopy is scheduled.
Other Name: SelenoExcell

Primary Outcome Measures :
  1. Number of Recurrent Adenomas at Surveillance Colonoscopy [ Time Frame: 3 to 5 years after baseline colonoscopy ]
    Detection of metachronous colorectal adenomas during follow-up, by treatment, in the original cohort. Surveillance colonoscopy is recommended 3 to 5 years after removal of colorectal adenoma(s). Participants will remain on the study intervention until their surveillance colonoscopy. Surveillance colonoscopy is determined by participants' GI physician.

  2. Median Selenium Blood Levels at One Year. [ Time Frame: One year ]
    Adequate adherence to long-term selenium treatment as measured by blood selenium levels (ng/mL) at one year.

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

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Ages Eligible for Study:   40 Years to 80 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes


  • 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



  • 40 to 80

Performance status

  • SWOG 0-1

Life expectancy

  • Not specified


  • Hemoglobin > 11 g/dL
  • WBC 3,000 - 11,000/mm^3


  • AST and ALT < 2 times upper limit of normal
  • Bilirubin < 2.0 mg/dL


  • Creatinine < 1.9 mg/dL


  • 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


  • 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


Biologic therapy

  • No concurrent drugs that regulate the immune system


  • No concurrent chemotherapy

Endocrine therapy

  • Not specified


  • No concurrent radiotherapy


  • See Disease Characteristics


  • 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

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT00078897

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United States, Arizona
Veterans Affairs Medical Center - Phoenix
Phoenix, Arizona, United States, 85012
Virginia G. Piper Cancer Center at Scottsdale Healthcare - Shea
Scottsdale, Arizona, United States, 85258-4512
Mayo Clinic Scottsdale
Scottsdale, Arizona, United States, 85259-5499
Arizona Cancer Center - Tucson Clinic
Tucson, Arizona, United States, 85724-5024
United States, Colorado
University of Colorado Cancer Center at UC Health Sciences Center
Denver, Colorado, United States, 80220
United States, New York
Endoscopy Center of Western New York
Williamsville, New York, United States, 14221
United States, Texas
Baylor University Medical Center - Dallas
Dallas, Texas, United States, 75246
Sponsors and Collaborators
University of Arizona
National Cancer Institute (NCI)
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Principal Investigator: M. Peter Lance, MD University of Arizona
Additional Information:
Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
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Responsible Party: University of Arizona
ClinicalTrials.gov Identifier: NCT00078897    
Other Study ID Numbers: CDR0000353185
P30CA023074 ( U.S. NIH Grant/Contract )
P01CA041108 ( U.S. NIH Grant/Contract )
First Posted: March 9, 2004    Key Record Dates
Results First Posted: September 24, 2019
Last Update Posted: September 24, 2019
Last Verified: September 2019
Keywords provided by University of Arizona:
colon cancer
rectal cancer
colorectal cancer
adenomatous polyp
Additional relevant MeSH terms:
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Colorectal Neoplasms
Precancerous Conditions
Adenomatous Polyps
Intestinal Neoplasms
Gastrointestinal Neoplasms
Digestive System Neoplasms
Neoplasms by Site
Digestive System Diseases
Gastrointestinal Diseases
Colonic Diseases
Intestinal Diseases
Rectal Diseases
Pathological Conditions, Anatomical
Neoplasms, Glandular and Epithelial
Neoplasms by Histologic Type
Molecular Mechanisms of Pharmacological Action
Protective Agents
Physiological Effects of Drugs
Trace Elements