Malignant esophageal fistula occurs infrequently, yet remains one of the most challenging complications encountered in thoracic oncology. It may occur in the setting of complicated esophageal cancer, presenting at an advanced stage of disease, or as a complication of treatment. The fundamental tenets of successful management of any fistula, such as relief of distal obstruction, treatment of infection, nutrition, and treatment of underlying malignancy, should be kept in mind but unfortunately are inherent to the disease process and usually overwhelming for patient and clinician. Improvements in completely covered self-expanding metallic stents (SEMSs) and associated delivery systems have dramatically changed the approach to managing esophageal fistulae, particularly involving the tracheobronchial tree. Palliation and not cure is the objective in the majority of patients afflicted with this uniformly fatal complication, which most often occurs in the setting of advanced stage disease. A multidisciplinary approach to accurate and precise diagnosis and treatment is essential.
General Principles: Patient Evaluation and Diagnosis
Malignant esophageal fistula usually presents with clinical symptoms of recurrent aspiration or less commonly hemoptysis or hematemesis. An esophageal fistula may also be suspected on the basis of transmission of oral flora through the fistula tract and the development of associated infection of the body cavity or organ in communication with the esophagus, such as recurrent pneumonia, empyema, and abscess. The majority of patients will present with known locally advanced or metastatic tumor and will frequently already be undergoing treatment with chemotherapy and radiation. The diagnosis is confirmed with fluoroscopy during administration of dilute barium oral contrast followed by thin-cut computed tomography (CT), which will usually define the precise location and extent of the fistula. A small fistula may be missed on radiographic evaluation and aspiration of swallowed barium can be confused with a fistula to the respiratory tract, particularly with proximal third esophageal lesions. Flexible esophagoscopy and bronchoscopy often are required for confirmation and anatomic assessment of the suspected fistula and provide additional information needed for treatment planning in addition to the therapeutic benefit of clearing the contaminated airway.
A tracheobronchial–esophageal fistula is often visualized more easily with bronchoscopy rather than esophagoscopy, as the esophageal mucosal folds and tumor sometimes obscure the origin of the fistula. It is also important to visualize any luminal compromise of the airway from tumor compression, as this may be exacerbated with esophageal stenting.
Once the diagnosis is established, broad-spectrum antibiotics should be instituted to include coverage for gram-positive bacteria, anaerobes, and yeast. Oral intake should be withheld and alternative forms of nutrition established. The ensuing treatment plan should then be directed toward:
Limiting or eliminating ongoing contamination of the respiratory tract or other body cavities.
Draining contained foci of infection such as the pleural, peritoneal, and pericardial spaces.
Maintaining adequate nutrition for healing.
Minimizing distal obstruction.
Treating the cancer if feasible.
Traditionally, contamination was controlled by surgical exclusion or diversion with a cervical esophagostomy and possible placement of a gastrostomy to limit reflux contamination, along with a jejunal feeding tube. Any contaminated fluid collections identified in the mediastinum, pleural space, peritoneal cavity, or pericardium should be adequately drained percutaneously or surgically.
Partially or fully covered SEMSs are now the primary treatment option for most fistulae, and offer an attractive alternative to some of the described surgical options. It is important to remember that contaminated fluid collections still require drainage. Primary thoracoscopic debridement and decortication may prevent the need for thoracotomy. Advantages of SEMSs in the management of esophageal fistulae related to esophageal cancer include ease and expediency of deployment with essentially immediate control of ongoing contamination from both antegrade and retrograde secretions. Tumor or treatment-related stricture and associated obstruction distal to the fistula are effectively managed simultaneously with stent placement across the fistula and through the stricture or obstructed lumen of the esophagus. Oral enteral nutrition can be resumed promptly without the need for a surgically placed feeding tube. The most common clinically significant complication of SEMSs is stent migration, which is more common in the absence of stricture or partial obstruction by tumor. It is important, particularly in the absence of stricture, to maximize the diameter and length of the stent both to increase the purchase of the stent and decrease migration. As well, it is important to ensure that the length of the covered portion of the stent extends 2 to 4 cm proximal and distal to the fistula. The stent should be long enough to include any stricture, both to facilitate oral intake and minimize stent migration. More than one stent occasionally may be required. SEMSs successfully control the fistula in essentially all patients with a very low complication rate.1
Preoperative Assessment and Patient Selection
Once the diagnosis is confirmed, it is important to determine the location (proximal, middle, or distal third of the esophagus) of the fistula, its size, communication with other organs or body cavities, presence or absence of abscess cavities or effusions, and whether it is wholly contained within the mediastinum. Broad-spectrum antimicrobial coverage already should have been instituted, often even before the diagnosis is established, and the patient should be resuscitated, stabilized, and the airway secured with endotracheal intubation if necessary. Each of these components are integral to making an adequate assessment of the fistula, along with CT and endoscopy as described above, and are essential to formulating a treatment plan.