The incidence of esophageal cancer has risen in recent decades accounting for 1.5% of all invasive cancers in 1996 alone.5 Occurring anywhere in the esophagus, cancer can exist as a stricture, mass, or plaque.
The most common symptom of esophageal cancer is dysphagia, or difficulty swallowing and the sensation that food is sticking on the way down the esophagus. Stents serve to bridge the obstruction in the esophagus and reestablish luminal patency.
Complications surrounding esophageal stents include overgrowth, ingrowth, and migration, and should be considered when choosing a stent for a patient. Manufacturers have been developing new ways to reduce and, when possible, eliminate these complications from occurring.
The first stents were composed of decalcified ivory and were eventually replaced by plastic stents. While plastic stents continue to be used today, primarily for reasons of cost, metal self-expanding stents are now the most widely accepted.
Studies have shown that while both plastic and metal prostheses can be effective, fewer stent-related complications occur with metal stents.
Coated stents are becoming increasingly common because of their ability to prevent tumor ingrowth.
Stents have proved to be a reliable way to alleviate dyphagia, which, without treatment, leads to poor quality of life, rapid weight loss, and a relatively quick and unpleasant death from total dysphagia and aspiration of the patient’s own saliva.4
One clinical investigation states: “Considering current survival outcomes, it is undesirable to distress these patients with painful and time-consuming procedures, prolonged hospitalization, or repetitive treatment sessions. In view of the short life expectancy of these patients, stent placement proves to be a safe and cost-effective method for management of dysphagia in malignant esophageal obstruction.”5
Studies show that 90% of patients can return to eating normal foods again following stent placement.1
Boston Scientific Microvasive Endoscopy offers two lines of self-expanding metal stents. The Wallstent® and Ultraflex™ esophageal stents are designed to maintain esophageal luminal patency in esophageal strictures caused by intrinsic and/or extrinsic malignant tumors, and occlusion of concurrent esophageal fistula.
The Wallstent has an angled, uncovered flare-end design with a large internal diameter and is available in various lengths. The stent is designed to be pre-mounted on the 18 Fr Delivery System with recapture and reposition option at up to 50% deployment.
The Ultraflex Esophageal Stent System has a single-strand nitinol construction designed to exert constant, gentle radial pressure, and minimize traumatic tissue compression. The polyurethane covering provides a barrier to resist tumor ingrowth.
“The flexible knitted loop design of the Ultraflex nitinol stent and a user-friendly delivery system are features that gastroenterologists are very keen about,” says Alexandra Rousseau, global product manager of esophageal and TB stents for Boston Scientific Microvasive Endoscopy.
Another company involved in the development of esophageal stents is Wilson-Cook Medical GI Endoscopy. The company’s line of Z-stents is also coated with a polyethylene film and are designed in a double flare configuration. Central fixation barbs facilitate stabilization within the esophagus. The inner diameter of the stent is 16mm.
Greg Skerven, vice president of product development for Wilson-Cook, says the company’s products include features that help prevent stent migration after placement.
“There is a flange on [each end of the stent] that is larger than the body of the stent,” he says. “When it expands, it is pressing out on the tumor. It is funnel-shaped so that keeps it from moving downward and upward.”
Wilson-Cook recently collaborated with Kulwinder S. Dua, MD, of the Department of Gastroenterology and Hepatology at Froedtert and Medical College in Milwaukee, Wisconsin in the development of an esophageal anti-reflux stent created specifically for tumors in the lower esophageal, gastroesophageal (GE) junction area.
Dua says cancers in this location make up the majority of the approximately 12,000 new cases of esophageal cancer diagnosed each year. When a stent partially bridges the GE junction, the stomach, and the esophagus essentially become a common cavity. Dua says patients run the risk of drowning in their own food when they lie down.
“People have reported a reflux disease resulting from a stent placed across the GE junction in anywhere from 20 to 70% of instances. Many have also reported aspiration and death from stents across the GE junction,” Dua says.
The idea Dua decided to market through Wilson-Cook was a valve that could be incorporated into an expandable stent to prevent food from backing into the esophagus. The valve is pressure sensitive, allowing patients to belch or vomit when necessary. The gastric pressure actually flips the valve inward, while two swallows of water restore the valve to its original position.
Dua emphasizes the importance of keeping current with deployment techniques.
- “The worst thing that can happen is when doctors who have put in hardly any stents suddenly want to put a stent in a complicated case with an anti-reflux valve that has a unique delivery system, and they run into problems,” he adds.
- Dua says ease of placement and a user-friendly delivery system are some of the most important criteria to consider when choosing an esophageal stent. He also said it is a common misconception in the medical field that one size or shape fits all. Certain tumors will necessitate a stent with a high radial force that will not buckle easily. In patients who have received chemotherapy or other combinations of treatment that can soften the esophageal wall, however, a strong radial force could lead to perforation.
- Other treatment options for esophageal cancer include various combinations of surgery, chemotherapy, radiation therapy, photodynamic therapy, and endoscopic therapy. The disease is rarely curable, with the overall 5-year survival rate in those cases amenable to surgery ranging from 5 to 20%.3 While early detection leads to a better chance of survival, tumors confined to esophageal mucosa or submucosa are usually detected by chance.
- The two most common types of esophageal cancer are adenocarcinoma and squamous cell or epidermoid carcinoma. Most patients with primary adenocarcinoma of the distal esophagus first have Barrett’s esophagus, a condition resulting from gastroesophageal reflux disease (GERD) and reflux esophagitis.
- Palliative treatments of malignant dysphagia include peroral dilation, thermal laser, photodynamic laser, chemical ablation, and the placement of stents. Palliative methods are required by a patient and are the most important contributions to care, considering curing esophageal cancer is rare.2