Abstract
Obesity is a complex disease involving an excessive amount of body fat. It is a medical problem that increases the risk of other diseases and health problems, such as heart disease, diabetes, high blood pressure, and certain cancers. It is unclear whether the risk of gastric cancer (GC) increases owing to bariatric surgery; however, the overall risk of cancer is greatly affected by high body mass index (BMI). This review aimed at exploring
the effects of obesity and bariatric surgery on GC. A filtration procedure was used to remove duplicates and irrelevant publications. The online databases, PubMed and Google Scholar, were used to carry out a literature search for publications published between 1998 and 2020, without any date or language restrictions. We used a combination of relevant search terms like “the influence of obesity and bariatric surgery on gastric cancer, obesity and bariatric surgery, bariatric surgery and stomach cancer, obesity and gastric cancer, world, and population”. We independently identified publications and systematically screened titles, abstracts, and full texts of the collected publications. Among 51 articles initially selected based on the title and abstract, 20 articles were excluded as it did not match the inclusion criteria. Finally, 31 articles were selected and included in the review. Previous studies have shown that there is an association between esophageal adenocarcinoma and high BMI, metabolic risk factors (glucose, cholesterol, and triglycerides), and blood pressure, independently of each other. Also, Helicobacter pylori, gastroesophageal reflux disease, inflammatory factors, and pathological changes are other risk factors that were reported to affect esophageal adenocarcinoma. Currently, there is a lack of evidence confirming the association between gastric adenocarcinoma and bariatric surgery. Therefore, program surveillance immediately after surgery is not recommended.

Key words: Bariatric surgery, obesity, gastric cancer (GC), high body mass index (BMI), the esophagus-gastric junction (EGJ), gastroesophageal reflux disease (GERD)