Barretts esophagus and esophageal adenocarcinoma: East versus West

Based on the American College of Gastroenterology guidelines, Barrett’s esophago (BE) is defined as a change in the distal esophageal epithelium that can be recognized as columnar type mucosa at endoscopy and is histologically confirmed to have intestinal metaplasia. The development of BE has also been associated with gastroesophageal reflux disease (GERD). Other risk factors related to BE include smoking, age, male gender, etc. Helicobacter pylori infection has been reported to be negatively associated with BE [1] . As a consequence of the clinical and epidemiological evidence supporting the association between BE and esophageal adenocarcinoma (EAC), BE is considered a precancerous lesion of EAC. Based on that definition, the prevalence of BE in Asia ranges from 0.06% to 6.2% [1] . The reported prevalence of BE in Western countries has varied from 0.9% to 4.5% in the general population and from 6.3% to 13.6% in patients with GERD [2] .

Wang et al [3] conducted a retrospective study which collected 425 cases with BE, and of these, 15 cases with EAC. This study aimed to investigate the clinical characteristics and risk of EAC in patients with BE. Most of the patients with EAC (14/15) underwent EGD due to alarming symptoms that included heart burn, acid regurgitation, dysphagia, and gastrointestinal bleeding. Among 15 patients with EAC, BE and EAC were diagnosed simultaneously on first EGD for 14 cases with the 15^th case having high grade dysplasia. However, most of them were of late stages. This study emphasized the importance of screening EGDs for patients with alarming symptoms (which offer significant clues in making the diagnosis of EAC). However, due to lack of a comprehensive endoscopic surveillance protocol for BE, no early EAC or high grade dysplasia could be detected during the follow-up period in this study.

The incidences of EAC have been increasing rapidly since the 1970s in most Western countries such as the UK, USA, Australia, etc. This has led to the incidences of EAC exceeding the incidences for esophageal squamous cell carcinoma in these countries [2]  ;  [4] . The risk factors of EAC included BE, GERD, age, male gender, body mass index, and tobacco smoking [2] ; [5]  ;  [6] . H. pylori infection has a negative association with development of EAC, however, the mechanism is unclear [7] . BE has been regarded as the most important factor leading to EAC, and it is closely related to GERD. Patients with BE have a 30- to 60-fold risk relative to the general population in developing EAC [2]  ;  [5] . The overall risk of EAC development in patients with BE is estimated to be approximately 0.12–0.5% per year [8] ; [9]  ;  [10] . Therefore, regular endoscopic surveillance has been recommended for BE to detect the occurrence of EAC in Western countries.

In Asia, although an increasing incidence of GERD has been noted in recent years, BE and EAC remain rare [11] ; [12]  ;  [13] . Currently, squamous cell carcinoma accounts for the majority of esophageal cancer. Based on the trend from epidemiologic data generated from Western countries, it is expected that incidence of BE in Asia could rise and EAC might be more common in the future. However, the 5-year survival rate for EAC is poor. How to make an early diagnosis of EAC to improve the overall survival is a critical issue. Endoscopic therapies such as radiofrequency ablation, endoscopic mucosal resection, and endoscopic submucosal dissection have been proven to be efficacious for the treatment of early EAC or BE with dysplasia in many studies from Western countries. Therefore, more prospective studies focusing on endoscopic screenings for patients with UGI alarming symptoms and endoscopic surveillance for patients with BE are necessary to provide stronger evidence in Asia.

Conflicts of interest

All authors declare no conflicts of interest.

References

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