Oncometabolic surgery: Emergence and legitimacy for investigation

Studies on morbid obesity have shown remarkable improvement of diabetes in patients who have undergone bariatric operations. It was subsequently shown that these operations induce diabetes remission independent of the resultant weight loss; as a result, surgeons began to investigate whether operations for gastric cancer (GC) could have the same beneficial effect on diabetes as bariatric operations. It was then shown in multiple reports that followed that certain operations for GC were able to improve or even cure type 2 diabetes mellitus (T2DM) in GC patients. This finding gave rise to the concept of "oncometabolic surgery", in which a patient diagnosed with both GC and T2DM undergo a single operation with the purpose of treating both diseases. With the increasing incidence of T2DM, oncometabolic surgery has the potential to improve the quality of life and even extend survival of many GC patients. However, because the GC patient population and the bariatric patient population are wildly different and because different GC operations have different properties, the effect of oncometabolic surgery must be carefully assessed and engineered in order to maximize benefit and avoid harm. This manuscript aims to summarize the findings made so far in the field of oncometabolic surgery and to provide an outlook regarding the possibility of oncometabolic surgery being incorporated into standard clinical practice.