Folic Acid in Preventing Colorectal Polyps in Patients With Previous Colorectal Polyps

Study Overview
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Brief Summary
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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.

Detailed Description
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OBJECTIVES: Primary Determine if folic acid supplementation lowers the adenoma recurrence rate. Secondary 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.

Official Title
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The Nurses' Health Study (NHS) and Health Professionals Follow-Up Study (HPFS) Folic Acid Prevention Trial

Conditions
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Adenoma of Large Intestine

Intervention / Treatment
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* Dietary Supplement: Folic acid
* Other: Placebo


Participation Criteria
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Eligibility Criteria
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DISEASE CHARACTERISTICS: Inclusion criteria: Participated in the Nurses' Health Study (NHS I) or the Health Professionals Follow-Up Study (HPFS) and have had a previous confirmed diagnosis of adenomatous polyp of the colon or rectum Plan on having an endoscopy within 4 years after initiation of the trial Must release medical records regarding past and any future endoscopies PATIENT CHARACTERISTICS: Inclusion criteria: Plasma vitamin B12 concentration of ≥ 300 pg/mL or have a vitamin B12 concentration between 200 and 299 pg/mL and a methylmalonic acid (MMA) level ≤ 32 µg/L Exclusion criteria: Diagnosis of cancer other than non-melanoma skin cancer, or early stage breast or prostate cancer Diagnosis of homocystinemia Diagnosis of pernicious anemia Any gastrointestinal disorder that could lead to a vitamin B12 deficiency Diagnosis of cirrhosis or pancreatitis Diagnosis of epilepsy, Alzheimer's disease, Parkinsonism, and psychiatric disorders that may interfere with normal functioning PRIOR CONCURRENT THERAPY: Exclusion criteria: No prior gastrectomy, total colectomy, or pancreatectomy Other concurrent multivitamins or supplements that contain folic acid (they may take specific supplements, such as A, C, E, calcium, and iron, or antioxidant formula vitamins) No concurrent methotrexate or anticonvulsant

Ages Eligible for Study
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Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Folic acid<br>Folic acid supplement 1g/day | Dietary Supplement: Folic acid<br>* Intervention group 1g folic acid per day<br>|
| Other: Placebo<br>Placebo pill once per day | Other: Placebo<br>* One placebo pill per day<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Recurrent colorectal adenoma |  | May 1996-March 2004 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| recurrent adenoma by location, size, stage, number, |  | May1996-March 2004 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Folic acid, Adenoma of Large Intestine