Standardizing endoscopic protocols increases detection of gastric cancer during surveillance of patients with precancerous conditions: a systematic review and meta-analysis

Patients with gastric atrophy (GA) and intestinal metaplasia (GIM) are considered to be at risk for gastric neoplasia (GN: dysplasia or cancer). During the last decades, standards of practice and endoscopic technologies have been developed and proposed. This meta-analysis reassesses GN incidence rates in GA and GIM patients, analyzing its evolution and the impact of standard protocols and scores. MEDLINE, Web of Science, and Scopus were systematically searched for cohort studies and Helicobacter pylori eradication or placebo arms of randomized controlled trials published after 2009 that allowed for the determination of the GN incidence rate in patients with GA or GIM. Common or random effects models were employed to calculate incidence rates, and heterogeneity was assessed using the I² statistic. Of 1242 studies, 15 met the inclusion criteria and were thus included. The annual incidence rates of GN (95 % confidence interval [CI]) were as follows: in GA patients, 0.21 % (95 % CI, 0.10-0.31) overall, 0.14 % (95 % CI, 0.00-0.42) for OLGA I/II, and 1.92 % (95 % CI, 1.37-2.47) for OLGA III/IV; in GIM patients, 0.57 % (95 % CI, 0.30-0.84) overall, 0.30 % (95 % CI, 0.00-0.69) for complete GIM, 1.08 % (95 % CI, 0.75-1.42) for incomplete GIM, 0.38 % (95 % CI, 0.09-0.68) for OLGIM I/II, and 1.12 % (95 % CI, 0.53-1.81) for OLGIM III/IV. When comparing studies using or not several histologic or endoscopic methods, the incidence rates of GN for both precancerous conditions were consistently higher than in those that did not: for the Sydney and/or MAPS biopsy protocols - in GA, 0.26 % (95 % CI, 0.08-0.44) vs. 0.17 % (95 % CI, 0.00-0.41); in GIM, 0.86 % (95 % CI, 0.35-1.36) vs. 0.44 % (95 % CI, 0.13-0.74); for the OLGA/OLGIM histological scores - in GA, 0.27 % (95 % CI, 0.08-0.46) vs. 0.16 % (95 % CI, 0.02-0.31); in GIM, 0.81 % (95 % CI, 0.27-1.36) vs. 0.47 % (95 % CI, 0.16-0.78); and for high-resolution endoscopy - in GA, 1.61 % (95 % CI, 0.32-2.90) vs. 0.19 % (95 % CI, 0.09-0.30); in GIM, 0.74 % (95 % CI, 0.15-1.33) vs. 0.52 % (95 % CI, 0.21-0.82). Patients with advanced stages of GA or GIM (OLGA/OLGIM stages III/IV) present >1 % annual risk for gastric cancer, meriting surveillance. Importantly, the application of validated histological and endoscopic methods that improve the quality of procedures influences the detection rate of GN.