Systematic review: gastric cancer incidence in pernicious anaemia

Background Pernicious anaemia (PA) has an increased risk for gastric cancer (GC). It is not established whether PA patients need to undergo endoscopic/histological follow-up. Aim To provide a systematic overview of the literature on PA and the development of gastric cancer, to estimate the gastric cancer incidence-rate. Methods According to PRISMA, we identified studies on PA patients reporting the incidence of gastric cancer. Quality of studies was evaluated using the Newcastle-Ottawa Quality Assessment Scale. Meta-analysis on annual gastric cancer incidence rates was performed. Results Twenty-seven studies met eligibility criteria. 7 studies were of high, 6 of medium, 10 of low and 4 of very low quality. Gastric cancer incidence-rates ranged from 0% to 0.2% per person-years in 7 American, from 0% to 0.5% in 2 Asiatic, from 0% to 1.2% in 11 Northern European studies and from 0% to 0.9% in 7 studies from other European countries. The incidence-rates of gastric cancer ranged from 0% to 1.2% per person-years in studies which used gastroscopy, from 0.1% to 0.9% in those based on International Classification of Disease. Heterogeneity between studies was not statistically significant at the 5% level (Chi-squared test = 17.9, P = 0.08). The calculated pooled gastric cancer incidence-rate was 0.27% per person-years. Meta-analysis showed overall gastric cancer relative risk in PA as 6.8 (95% CI: 2.618.1). Conclusions This systematic review shows a pooled gastric cancer incidence-rate in pernicious anaemia of 0.27% per person-years and an estimated nearly sevenfold relative risk of gastric cancer in pernicious anaemia patients. Further high quality studies are needed to confirm this higher risk.