[573] Gastric Atrophy Diagnostic Accuracy: Comparison of OLGA with Baylor System

HMT El-Zimaity, RH Riddell, S Abudayyeh, AR Opekun, DY Graham. McMaster University, Hamilton, ON, Canada; Mount Sinai Hospital, Toronto, ON, Canada; Baylor College of Medicine, Houston, TX

Background: The risk of developing intestinal type gastric cancer is related to the extent of atrophy. Two histopathologic based systems (OLGA, and Baylor) have been introduced as an index of gastric atrophy. OLGA incorporates the updated Sydney System (SS) biopsy protocol (3 antral and 2 mid-corpus biopsies along the lesser and greater curvature) and a histopathology scoring system averaging scores by region then combines these scores. Baylor uses Baylors biopsy protocol (which uses SS but adds 2 additional distal corpus biopsies) and scores the antrum and corpus independently. Antral atrophy stage is an average score, but corpus atrophy stage is independent of antral atrophy, independent of individual reading in each biopsy but dependent on location. As corpus atrophy starts at the incisura and extends in continuity proximally and towards the greater curve, atrophy in a distal biopsy is early and atrophy in the most proximal location is advanced. This study compares the diagnostic accuracy of each system.
Design: Biopsies were examined from 127 patients who had endoscopy with biopsy using Baylors protocol. OLGA and Baylor atrophy scores were compared with serum pepsinogen I/II ratio as a marker for corpus atrophy and serum gastrin level as a marker for antral atrophy.
Results: Baylor System of scoring corpus atrophy by location was superior to OLGAs average score from all biopsies (p < 0.0001). Incorporating distal corpus biopsies improved corpus atrophy recognition (p <0.0001) but did not affect the overall OLGA stage (p = 0.6); OLGA was heavily influenced by antral atrophy score, enough to show a positive (not negative) correlation with serum gastrin levels. Corpus atrophy was identified in 57 (36%) patients using Baylor compared to 33 (26%) using OLGA (< p = 0.001). Baylor System showed that, in the antrum, the extent of intestinal metaplasia, and not just antral gland atrophy, correlated best with decreasing fasting serum gastrin levels. Patients with autoimmune gastritis were unrecognized in OLGA but readily identified using Baylor.
Conclusions: In following the SS biopsy site and scoring system recommendations, OLGA systematically underestimated the presence of corpus atrophy and thus cancer risk. In addition, diagnostic information was lost in lumping comparative measures (antral versus corpus atrophic gastritis). Studies for cancer risk should use the Baylor system (biopsy protocol and scoring system).
Category: Gastrointestinal

Wednesday, March 11, 2009 1:00 PM

Poster Session VI # 85, Wednesday Afternoon