Recent advancements in stent therapy in patients with malignant gastroduodenal outlet obstruction

Gastric outlet obstruction (GOO) is one of severe comorbidities caused by many kinds of malignant diseases and is associated with not only degradation of patients' quality of life but also mortality. Although surgical bypass is one of the main therapies for malignant GOO, it is often difficult to perform in end-stage patients. The deployment of self-expandable metallic stents (SEMSs) has recently become a viable alternative to surgical bypass for malignant GOO. This technique is less invasive and more effective, particularly in patients with poor prognoses. Many reports have referred to the feasibility, effectiveness, and safety of the placement of SEMSs for malignant GOO. According to these reports, the rates of technical and clinical success were reported to be relatively high and the rate of adverse events to be acceptable. However, precautions against severe adverse events such as massive bleeding and perforation are necessary. Several reports have described the differences in clinical results among different kinds of SEMSs. The presence of a covered design for SEMSs may affect the patency of SEMSs and the rate of stent dysfunction. Selection of the SEMS according to axial force may affect successful achievement of long patency of SEMSs and avoidance of gastroduodenal perforation at the bending site of the duodenum. Compared with high technical success rates nearing 100%, clinical success rates were usually lower than technical success. Therefore, determination of predictive factors for failure of clinical success is important. Several papers reported that low performance status could be associated with failure of clinical success. However, the association of clinical success with other factors such as carcinomatosa and ascites remains controversial, which is a problem to be solved. Reintervention with SEMS using the stent-in-stent method after stent dysfunction can be performed effectively as well as placement of the first SEMS.