Folic Acid in Preventing Colorectal Polyps in Patients With Previous Colorectal Polyps
RATIONALE: Chemoprevention is the use of certain substances to keep cancer from forming. The use of folic acid may prevent colorectal cancer.
PURPOSE: This randomized clinical trial is studying how well folic acid works compared with a placebo in preventing colorectal polyps in patients who have had previous colorectal polyps.
|Study Design:||Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double Blind (Subject, Investigator)
Primary Purpose: Prevention
|Official Title:||The Nurses' Health Study (NHS) and Health Professionals Follow-Up Study (HPFS) Folic Acid Prevention Trial|
- Recurrent colorectal adenoma [ Time Frame: May 1996-March 2004 ] [ Designated as safety issue: No ]
- recurrent adenoma by location, size, stage, number, [ Time Frame: May1996-March 2004 ] [ Designated as safety issue: No ]
|Study Start Date:||May 1996|
|Estimated Study Completion Date:||January 2016|
|Primary Completion Date:||March 2004 (Final data collection date for primary outcome measure)|
Folic acid supplement 1g/day
Dietary Supplement: Folic acid
Intervention group 1g folic acid per day
Placebo pill once per day
One placebo pill per day
- Determine if folic acid supplementation lowers the adenoma recurrence rate.
- Determine the number of adenomas per patient and the size and histology of the adenoma.
- Assess the interaction between folic acid and alcohol, methionine, and aspirin intake.
- Assess the interaction between folic acid and pretrial and midtrial folate levels.
- Assess other complementary biomarkers such as DNA methylation and blood folate level as risk factors for polyp recurrence.
OUTLINE: Patients are randomized to 1 of 2 treatment arms.
- Arm I: Patients receive oral folic acid once daily.
- Arm II: Patients receive oral placebo once daily. At least 1 year after beginning treatment, patients are sent a blood collection kit in order to measure plasma vitamin B12 levels, to measure folate to assess compliance.
|Principal Investigator:||Edward L. Giovannucci, MD, ScD||Dana-Farber/Brigham and Women's Cancer Center|