The primary application of<unk>  is in the palliation of tumours that obstruct the gastrointestinal tract. When they expand within the lumen, they are able to hold open the structure and allow passage of material, such as food, stool, or other secretions. The usual applications are for cancers of the esophagus, pancreas, bile ducts and colon that are not amenable to surgical therapy.<unk>  are used to treat additional complications of cancer, such as tracheoesophageal fistulas from esophageal cancer, and gastric outlet obstruction from stomach, duodenal, or pancreatic cancer.<unk>  and<unk> -expanding plastic stents have also been used for non-malignant conditions that cause narrowing or leaks of the esophagus or colon. These include peptic strictures caused by esophageal reflux and perforations of the esophagus.<unk>  may also be placed in tandem fashion to treat ingrowth or overgrowth tumours, and fractures or migration of other<unk> . For the latter, the second<unk>  in usually deployed within the lumen of the first.<unk>  are also sometimes used in the vascular system, usually in the aorta and peripheral vascular system. In the past they have been used for saphenous vein graft and native coronary artery percutaneous coronary interventions.
Self-expandable metallic stent
Endoscopic stenting
Bare-metal stent
Embolization
Endoscopic submucosal dissection
Bioresorbable stent
Jejunoileal bypass
Natural orifice transluminal endoscopic surgery