No Association Between Eosinophilic Oesophagitis and Oesophageal Cancer in US Adults: A Case–Control Study

ABSTRACT Background While inflammation is implicated in the development of numerous cancers, whether eosinophilic oesophagitis (EoE) increases the risk of oesophageal cancer (OCa) remains understudied. Aim To assess whether adults with EoE were more likely to have subsequent OCa diagnosis. Methods This case–control study used data from the MarketScan commercial claims database. Cases were 18–64 years old with an oesophageal cancer diagnosis (≥ two coding instances) who had no previous oesophageal cancer code. Controls were matched 10:1 by age and time in health plan. All cases and controls had at least 2 years of continuous healthcare coverage before the index date. EoE status required ≥ two coding instances. We used conditional logistic regression modelling to assess the association between EoE and oesophageal cancer. Results Of 5562 eligible cases and 55,620 matched controls, median age was 58.8 years and median number of years in health plan was 5.1. The proportions of male cases and controls were 81.3% and 41.4%, respectively. A history of EoE was rare in both cases and controls. Only two oesophageal cancer cases (0.04%) and 44 controls (0.08%) had evidence of an EoE diagnosis (OR 0.46; 95% CI 0.11–1.88). Conclusions EoE is not associated with the development of oesophageal cancer in privately insured adults under 65 years old; co‐incidence of EoE and oesophageal cancer is extremely rare. Additional studies are needed to confirm these findings and to evaluate whether they hold in older adults or over longer follow‐up, and whether EoE might protect against oesophageal cancer. In this case–control study using administrative claims data, EoE was not associated with the development of oesophageal cancer in privately insured adults under 65 years old, and co‐incidence of EoE and oesophageal cancer was extremely rare.