RATIONALE: Studying tissue samples in the laboratory from participants receiving treatment on the Selenium and Vitamin E Cancer Prevention Trial (SELECT) SWOG-S0000 may help doctors predict a participant's response to treatment and help plan the best treatment. PURPOSE: This phase III trial is studying the effect of vitamin E and/or selenium on colorectal polyps in men enrolled on SELECT Trial SWOG-S0000.
OBJECTIVES: Primary * To assess the effect of selenium on colorectal adenoma (CRA) occurrence. * To assess the effect of selenium on number, location, size, histologic type, and degree of dysplasia of CRA. * To assess the effect of selenium on colorectal cancer (CRC) incidence. Secondary * To assess the effect of vitamin E on CRA occurrence. * To assess the effect of vitamin E on CRC incidence. Tertiary * To explore the effect modification of selenium and vitamin E by aspirin on CRA occurrence. * To explore the effect modification of selenium and vitamin E by body mass index. OUTLINE: This is a multicenter study. Endoscopically obtained tissue samples are reviewed by study pathologists to confirm the presence (or absence) of a colorectal adenoma (CRA). If a CRA is present, the number, location, size, histology, and degree of dysplasia are documented. The CRA is also reviewed to exclude a diagnosis of colorectal cancer. Additional data, including aspirin use, height and weight, date of birth, and other demographic and baseline characteristics, is also obtained. Participants' medical records are reviewed periodically. Participants are followed annually.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
QUADRUPLE
Enrollment
8,094
Arizona Cancer Center
Tucson, Arizona, United States
Effect of Selenium on Colorectal Adenoma (CRA) Occurrence, Analyzed by Active Selenium vs. Selenium Placebo
Time frame: From 1 year post randomization through study completion
Effect of Selenium on Advanced Neoplasia, Analyzed by Active Selenium vs. Selenium Placebo
Adenomas with diameter \>=1cm or any adenoma with villous features or high-grade dysplasia
Time frame: From 1 year post randomization through study completion
Effect of Selenium and/or Vitamin E on Colorectal Cancer (CRC) Incidence
Time frame: From 1 year post randomization through study completion
Effect of Selenium on Occurrences of Multiple (>2) Adenomas
Time frame: From 1 year post randomization through study completion
Effect of Vitamin E on CRA Occurrence, Analyzed by Active Vitamin E vs. Vitamin E Placebo
Time frame: From 1 year post randomization through study completion
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1 pill by mouth daily for 7 - 12 years