Aberrant crypt focus size predicts distal polyp histopathology.

Aberrant crypt foci (ACF) are the earliest histopathologic lesion associated with colorectal cancer. ACFs are commonly used as a surrogate marker for colorectal cancer chemoprevention studies in rodents and, more recently, in humans. However, ACF prevalence in unselected populations is not known, nor which ACF features are important for predicting polyp histopathology. To address these questions, we did magnification chromo-colonoscopy on all patients undergoing routine colorectal cancer screening over a 31-month period. ACFs were classified by location, size (small, <20 crypts/ACF; medium, 20-100 crypts/ACF; large, >100 crypts/ACF), and whether they were elevated above the tissue plane. Overall, 802 magnification chromo-colonoscopies with ACF enumeration were done. Mean patient age was 58.6 +/- 8.5 years, of whom 56% were female, 58% were African American, 21% were Caucasian, and 16% were Latino. Total ACF number, along with increasing ACF size and elevation, correlated with the presence of distal hyperplastic polyps and were higher in African Americans. In contrast, ever-smaller ACFs correlated with the presence of distal adenomas and were independent of age and race. The odds ratio for patients with >or=6 small ACFs and adenomas was 6.02 (95% confidence interval, 2.64-13.70) compared with patients with or=1 large ACF and hyperplastic polyps was 5.88 (95% confidence interval, 3.00-11.67) compared with patients with none. Small flat ACFs correlate with the presence of distal adenomas, whereas large raised ACFs correlate with the presence of hyperplastic polyps.

Relationship of aging and tobacco use with the development of aberrant crypt foci in a predominantly African-American population.

BACKGROUND AND AIMS: In clinical studies, diminished folate availability appears to increase the risk for colorectal neoplasms. Additionally, alcohol and tobacco use are associated with an increased risk for colon cancer, but the early pathologic events by which these agents promote neoplastic transformation are not well understood. Aberrant crypt foci (ACF) are potential precursors of adenoma and cancer, and can be visualized by magnification endoscopy. We hypothesized that folate depletion is linked to ACF formation and therefore studied the association between tissue folate, dietary habits, and ACF number in patients undergoing screening colonoscopy. METHODS: Eighty-three patients, undergoing screening colonoscopy at an urban Veterans Affairs and university hospital, completed a questionnaire concerning alcohol, nonsteroidal anti-inflammatory drug (NSAID), and tobacco use. Folate intake was calculated from food frequency questionnaires. Rectal ACFs were scored using magnification chromoendoscopy (magnification, 35 x) by methylene blue staining. Folate concentrations in rectal biopsy specimens were determined by microtiter bioassay. RESULTS: ACF number increased with age and with increasing tobacco intake. Decreased colonic folate level was associated with increased homocysteine levels and lower dietary folate intake but did not correlate with ACF number. CONCLUSIONS: Increasing age and tobacco use were linked independently to the presence of colonic ACF in this predominantly African-American population. Folate, alcohol, and acetylsalicylic acid (ASA) use did not influence the prevalence of these lesions.