IntroductionThe incidence of esophageal cancers is increasing in many Western countries and the rate of missed esophageal cancers (MEC) at upper endoscopy is of concern. We aimed to calculate the MEC rate and identify factors associated with MEC.MethodsThis was a retrospective population-based cohort study including 613 patients diagnosed with esophageal cancer in Central Norway 2004–2021. MEC was defined as esophageal cancer diagnosed 6–36 months after a non-diagnostic upper endoscopy. Patient characteristics, tumor localization, histological type and cTNM stage were recorded. Symptoms, endoscopic findings, use of sedation and endoscopists experience at the endoscopy prior to esophageal cancer diagnosis and at the time of diagnosis were recorded. The association between these factors and MEC was assessed.ResultsForty-nine (8.0%) of 613 cancers were MEC. There was a significant increase in annual numbers of esophageal cancer (p < 0.001) as well as of MEC (p = 0.009), but MEC rate did not change significantly (p = 0.382). The median time from prior upper endoscopy to MEC diagnosis was 22.9 (12.1–28.6) months. MEC patients were older and were diagnosed with disease with a lower cTNM stage and cT category than non-missed cancers, whereas tumor localization and histological type were similar between the groups. The use of sedation or endoscopist experience did not differ between the endoscopy prior to esophageal cancer diagnosis and at the time of diagnosis. High proportions of MEC patients had Barrett’s esophagus (n = 25, 51.0%), hiatus hernia (n = 26, 53.1%), esophagitis (n = 10, 20.4%) or ulceration (n = 4, 8.2%). Significant proportions of MECs were diagnosed after inappropriate follow-up of endoscopic Barrett’s esophagus, histological dysplasia or ulcerations.ConclusionsThe annual number of MEC increased during the study period, while the MEC rate remained unchanged. Endoscopic findings related to gastroesophageal reflux disease such as esophagitis and Barrett’s esophagus were identified in a high proportion of patients with subsequent MECs. Cautious follow-up of these patients could potentially reduce MEC-rate.