Conditions: Colorectal Cancer Precancerous Condition
Keywords: colon cancer rectal cancer adenomatous polyp
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 8094
Healthy volunteers: yes

Brief summary:
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.

Detailed description:
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.

Arms:
arm 1: Vitamin E and selenium placebo daily for 7 - 12 years arm 2: Selenium and vitamin E placebo daily for 7 - 12 years arm 3: Vitamin E and selenium daily for 7 - 12 years arm 4: Vitamin E placebo and selenium placebo daily for 7 - 12 years

Interventions: intervention 1: Vitamin E intervention 2: Selenium intervention 3: Vitamin E placebo intervention 4: selenium placebo
Intervention descriptions: intervention 1: 400 IU daily by mouth for 7 - 12 years intervention 2: 200 mcg daily for 7 - 12 years intervention 3: 1 pill by mouth daily for 7 - 12 years intervention 4: 1 pill by mouth daily for 7 - 12 years

Protocol document: