Comments on Study About Bariatric Surgery and Gastroesophageal Cancer—Reply

Abstract

COMMENT & RESPONSEIn Reply We are pleased that our article 1 provokes debate and rightly so. We are fully aware of the limitations of our work, which we detail in the article. We would first like to mention that our conclusion is that bariatric surgery was associated with a significant reduction in the incidence of esophageal and gastric cancer and overall in-hospital mortality, which suggests that bariatric surgery can be performed as a treatment for severe obesity without increasing the risk of esophageal and gastric cancer.Both Liu and Yang as well as Chen and colleagues emphasized the difference in body mass index between the 2 groups after matching. Actually, body mass index was included in the Cox models, and we apologize if this point was not clear enough in the Methods section. In addition, unmeasured risk factors such as family predisposition, dietary or occupational exposure, and socioeconomic status could potentially confound the data. However, these factors should theoretically apply to populations who underwent operation and who did not undergo operation.Regarding surveillance during follow-up, the French guidelines recommend a follow-up upper gastrointestinal endoscopy at 1, 3, 5, and 10 years after sleeve gastrectomy, which is by far the most performed procedure in the country. 2,3 Moreover, sleeve gastrectomy is responsible for 20% of de novo gastroesophageal reflux disease and therefore in theory could promote the sequence of Barrett esophagus to esophageal cancer. 4 For these 2 reasons, we would have expected a significant increase in the rate of esogastric cancer diagnosis in patients undergoing surgery, which was not observed in this study.As described in our article, the detection and eradication of Helicobacter pylori has been systematic in the population undergoing bariatric surgery, which is one of the limitations of this work. However, H pylori is a proven risk factor for gastric cancer but not for cancer of the esogastric junction and esophagus, which accounts for almost half of the cancers diagnosed in both groups. Furthermore, the proportion of gastric and esophageal cancers was essentially the same between patients who underwent an operation (23% esophageal cancers) and those who did not (25% esophageal cancers), whereas if we consider H pylori eradication as a bias, we would have expected a reduction in the incidence of gastric cancer and an increase in the incidence of esophageal cancer in patients who underwent operation.For all these reasons and despite our imperfect model, we believe that bariatric surgery plays, directly and indirectly, an important role in reducing the incidence of gastric and esophageal cancer. Obviously, further studies will be needed to confirm our results.