The effects of calendar year, age and acid suppression medication on the amount of change in Barrett's esophagus surface area.

A6

Barrett's esophagus, a metaplastic transition of squamous epithelium to specialized intestinal epithelium, is a premalignant neoplasm leading to esophageal adenocarcinoma, and can serve as a model for studying clonal competition between normal and precancerous cells. We hypothesized that Barrett's cells can out-compete squamous cells in the acid environment of gastric reflux but when acid is controlled by medication, squamous cells may out-compete Barrett's cells, leading to regression. To determine whether factors, such as medication, age, and BMI, can modulate the amount of squamous vs. intestinal epithelium, we analyzed 4-quadrant biopsy data from 477 Barrett's esophagus patients over 2,814 person-years to estimate total BE surface area and account for squamous islands within the segment. Regression analyses showed a slight but significant increase in the amount of Barrett's tissue with increasing age (0.03cm per year, p<0.05) and calendar year (0.09cm per year, p<0.01) among patients on proton pump inhibitors (PPIs). Patients on PPIs exhibited dramatically more variation in the rate of change in Barrett's surface area compared to patients on H2 blockers (p < 0.001). This variation was not associated with body mass index, waist to hip ratio, cigarette use, non-steroidal anti-inflammatory drug use, or the number of biopsies taken in a prior endoscopy. Our results suggest that, on average, PPI's do not lead to regression of the Barrett's epithelium, and all acid suppression medications are associated with stable amounts of Barrett's epithelium over time. However, due to unknown factors, the Barrett's segments in a minority of patients on PPI's either grow or shrink rapidly. Future studies will examine factors that account for patients' variability in responsiveness to PPIs.