Progression of specialized intestinal metaplasia at the cardia to macroscopically evident Barrett's esophagus: an entity of concern in the ProGERD study

Histological Barrett's esophagus, defined as specialized intestinal metaplasia (SIM+) at the cardia without endoscopic suspicion of columnar epithelium, is found frequently in biopsies at the gastro-esophageal junction although its clinical relevance is unknown. The authors aim was to evaluate prospectively the progression of SIM+ to macroscopically evident Barrett's esophagus (BE/SIM+), and to identify risk factors for this progression.Data were obtained from a sub-group of patients (no visible BE at presentation, but SIM+) included in the ProGERD study, a prospective evaluation of the clinical course of GERD under routine clinical care. They had esomeprazole 20-40 mg/day for 2-8 weeks. Symptom assessment was performed annually, and endoscopy with biopsy was planned at baseline, after healing treatment and after 2 and/or 5 years.128 of 171 (74.8%) patients with unequivocal SIM at the z-line after healing were biopsied again after 2 and/or 5 years. At follow-up, 33 (25.8%) of these patients showed progression to BE/SIM+. Factors significantly associated with progression were smoking, a long history of GERD and severe esophagitis at baseline. Patients who had progressed to BE/SIM+ already at 2 years showed consistent findings at 5 years.More than 20% of GERD patients with SIM+ in this study were found to have BE/SIM+ within 2-5 years. This finding supports the hypothesis that SIM+ at the cardia could be the missing link explaining increased cancer risk in GERD patients without overt BE and merits further investigation in a prospective study.