Protocol Number: 02-C-0194
The primary objective of this study is to investigate the effects of celecoxib on rectal aberrant crypt foci among individuals with above average-risk for developing colorectal tumors. All subjects will be prospectively recruited from among adult colonoscopy patients seen at the National Naval Medical Center. Eligible participants will include patients found to have one adenoma greater than 1 cm in diameter or three adenomas greater than or equal to 5 mm in diameter (if 18-49 years of age) or one adenoma greater than or equal to 5 mm in diameter (if greater than or equal to 50 years of age) and at least 5 rectal aberrant crypt foci. Enrolled subjects (n=40) will be randomly assigned to receive either celecoxib 400 mg by mouth twice per day or placebo. After an intervention period of six months, a follow-up endoscopic (flexible sigmoidoscopy) examination of the distal colorectum will be performed. At the baseline colonoscopy procedure, rectal aberrant crypt foci will be quantitated and ascending and descending colon normal-appearing mucosa will be biopsied to measure proliferation, apoptosis, and gene expression biomarkers. The same will occur on the samples collected during the follow-up flexible sigmoidoscopy with biopsies of normal-appearing mucosa of the descending colon. Efficacy of the chemopreventive agent will be assessed by comparing pre-versus post-intervention changes across treatment arms. Informed consent for the baseline biomarker assessments will be documented prior to the initial colonoscopy. In most cases, the presence or absence of colorectal neoplasia will not be know prior to this procedure. Thus, we plan to obtain ascending and descending,normal,colonic mucosa samples from approximately 40 subjects with no colorectal adenomas and 40 subjects with at least one adenoma. Exact sample sizes will be determined by the subject subgroup distribution at the time of full accrual into the intervention trial. Colorectal neoplasms identified during the baseline colonoscopy will additionally be sampled to allow for biomarker comparisons to be made between normal and dysplastic tissues. As designed, this study will (1) provide novel data regarding the baseline prevalence and effects of celecoxib on rectal aberrant crypt foci among patients with sporadic colorectal adenomas and (2) help to clarify the utility of rectal mucosal biomarkers for ongoing and future chemoprevention research.
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Warren Grant Magnuson Clinical Center (CC) |
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