Folic acid supplementation inhibits recurrence of colorectal adenomas: a randomized chemoprevention trial.
OBJECTIVE
To determine whether folic acid supplementation will reduce the recurrence of colorectal adenomas, the precursors of colorectal cancer, we performed a double-blind placebo-controlled trial in patients with adenomatous polyps.


METHODS
In the current double-blind, placebo-controlled trial at this VA Medical Center, patients with colorectal adenomas were randomly assigned to receive either a daily 5 mg dose of folic acid or a matched identical placebo for 3 years. All polyps were removed at baseline colonoscopy and each patient had a follow up colonoscopy at 3 years. The primary endpoint was a reduction in the number of recurrent adenomas at 3 years.


RESULTS
Of 137 subjects, who were eligible after confirmation of polyp histology and run-in period to conform compliance, 94 completed the study; 49 in folic acid group and 45 in placebo group. Recurrence of adenomas at 3-year was compared between the two groups. The mean number of recurrent polyps at 3-year was 0.36 (SD, 0.69) for folic acid treated patients compared to 0.82 (SD, 1.17) for placebo treated subjects, resulting in a 3-fold increase in polyp recurrence in the placebo group. Patients below 70 years of age and those with left-sided colonic adenomas or advanced adenomas responded better to folic acid supplementation.


CONCLUSIONS
High dose folic acid supplementation is associated with a significant reduction in the recurrence of colonic adenomas suggesting that folic acid may be an effective chemopreventive agent for colorectal neoplasia.
Jaszewski
Richard
R
John D Dingell VA Medical Center, Detroit, MI 48201, USA.
Misra
Sabeena
S
Tobi
Martin
M
Ullah
Nadeem
N
Naumoff
Jo Ann
JA
Kucuk
Omer
O
Levi
Edi
E
Axelrod
Bradley N
BN
Patel
Bhaumik B
BB
Majumdar
Adhip P N
AP
D000236:Adenoma / Q000517:prevention & control*; D000368:Aged; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000517:prevention & control*; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D005492:Folic Acid / Q000627:therapeutic use*; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000517:prevention & control*; D012307:Risk Factors; D016896:Treatment Outcome
D005492:Folic Acid