Nahel A. Tunio, MD1, Mohammed Z. Sheriff, MD1, Gregory Cooper, MD2; 1Case Western Reserve University/University Hospitals Cleveland Medical Center, Cleveland, OH; 2University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, OH
Introduction: Chronic autoimmune gastritis leads to destruction of parietal cells of the stomach, resulting in B12 deficiency and pernicious anemia. Studies have suggested due to a less acidic stomach and chronic inflammation, patients with pernicious anemia are at higher risk of developing gastric cancer. We sought to describe the prevalence of gastric cancer in individuals with pernicious anemia in the US using a large population based database. Methods: We used a commercial database (Explorys Inc, Cleveland, OH), an aggregate of Electronic Health Record data from 27 major integrated healthcare systems in the US. Patients were identified using the Systemized Nomenclature of Medicine Clinical Terms between 1999 to present. We identified a cohort of patients aged >18 years old with “pernicious anemia” and a diagnosis of “primary malignant neoplasm of stomach” at least 180 days after the diagnosis of pernicious anemia. We compared the prevalence of gastric cancer in patients with pernicious anemia and patients without pernicious anemia. We also described the age-, gender- and race-based prevalence. Results: Of the 61,551,310 individuals active in the database, we identified 63,450 patients with pernicious anemia and the prevalence estimated was103 per 100,000 individuals. Among patients with pernicious anemia, 0.38% were found to have gastric cancer as compared to 0.035% in patients without pernicious anemia (figure 1), with odds ratio (OR) 10.72 (95% CI 9.44-12.18,p< 0.0001). The risk of gastric cancer was higher in males [OR 1.71 (95% CI 1.32-2.20,p< 0.0001)] as compared to females and elderly (aged >65yrs) [OR 2.67 (95% CI 1.89-3.75, p< 0.0001)] as compared to adults (aged 18 to 65yrs). There was no significant difference in prevalence between Caucasians and African-Americans (figure 2). Discussion: This is one of the large studies to date that describes the epidemiology of gastric cancer in patients with pernicious anemia in the USA. We found that the risk of gastric cancer is increased in patients with pernicious anemia as compared to patients without pernicious anemia. Moreover, the risk was particularly increased in male and elderly (aged >65yrs) patients. Given the higher risk of gastric cancer in patients with pernicious anemia, physicians should consider early endoscopic screening for gastric cancer.
Figure 1: Prevalence (per 100,000) of gastric cancer in individuals with pernicious anemia and without pernicious anemia in the United States
Figure 2: Gender-, Age- and Race-Based Prevalence (per 100,000) of gastric cancer in individuals with pernicious anemia and without pernicious anemia in the United States
Disclosures: Nahel Tunio indicated no relevant financial relationships. Mohammed Sheriff indicated no relevant financial relationships. Gregory Cooper indicated no relevant financial relationships.