567. EPIDEMIOLOGY OF BARRETT'S ESOPHAGUS IN ICELAND; INCIDENCE AND PROGRESSION TO NEOPLASM FROM A LARGE POPULATION-BASED STUDY

Abstract Background Barrett’s esophagus (BE) is the known precursor to esophageal adenocarcinoma (EAC). Previous studies have demonstrated a wide variety of progression rate whereas no nationwide data regarding the progression has been reported. The aims of the study were to evaluate the prevalence of BE and neoplasms in BE, and progression to those in a large population based and nationwide. Methods This was a retrospective study and patients from 7 institutions who were identified through a database of centralized pathology laboratory in an expert center. Demographics and relevant clinicopathological features were obtained from medical records of patients with a pathologically confirmed BE by presence of intestinal metaplasia between 1990 and 2022. Results A total of 811 patients were identified with BE, 551 men (67.9%), male to female ratio 2.1:1, and with a median age at diagnosis of 63 years (IQR 53-73). At the time of BE diagnosis, the prevalence of neoplasm was 13.9%, (56 LGD, 14 HGD, and 43 EAC). Out of 56 LGD, 16.1% progressed to HGD (n=6) or EAC (n=3). Among 698 BE patients without neoplasm at the time of BE diagnosis, the cumulative incidence of neoplasm was 6.9% (29 LGD, 7 HGD, and 12 EAC) with median observation-period of 7 years (IQR: 4-9). In total, 161 cases of neoplasm (65.8% in long-segment, 34.2% in short-segment BE) were diagnosed in this BE cohort; 67.2% at time of BE diagnosis; and 32.8% without dysplasia at diagnosis progressed to neoplasm during follow-up. Conclusion In this large population-based study of patients with BE, around 14% were diagnosed as harboring neoplasm concomitantly with BE, which accounted for approximately 67% of all neoplasms. During the median follow-up of 7 years, about 7% of BE showed dysplastic or malignant progression.