66: Cancers of the Upper Aerodigestive Tract: Cervical Exenteration

Rarely, locally extensive but nonmetastatic cancers of the upper aerodigestive tract require resection. Cancers of the larynx, cervical trachea, hypopharynx, cervical esophagus, and thyroid can be exenterated with a pharyngo-laryngo-tracheo-esophagectomy as primary therapy, salvage after failed primary therapy, treatment of locally recurrent cancer, treatment of benign complications of successful primary therapy, or long-term palliation. The enormity of these procedures is further overshadowed by the likely possibility of limited survival, the potential for significant complications, and the expected negative impact upon quality of life. However, in curatively resected and properly reconstructed patients, long-lasting effects are little more than that experienced by the laryngectomy patient.

Clinical staging is mandatory to determine the eligibility for exenteration.¹ Distant metastatic cancer (cM1 or ycM1) is excluded by PET/CT and cancer-specific imaging (e.g., thyroid scanning for differentiated thyroid cancers). Regional nodal metastases (cN1 or ycN1) are frequently detected by physical examination and confirmed by cytologic evaluation of fine-needle aspiration (FNA) specimens. However, cervical ultrasonography and FNA may be necessary to better examine and determine regional nodal classification. Local extent of the primary cancer (cT or ycT) is critical in deciding resectability, but is frequently underestimated by preoperative investigations. Regardless, local invasion should be evaluated with particular with respect to particular carotid artery, vertebral body, and mediastinal involvement. This may require multiple imaging modalities (angiography, MRI, fine-cut CT, barium esophagram, bone scan, etc.). The proximal and distal extent of the cancer is assessed by oropharyngoscopy, bronchoscopy, and esophagoscopy (panendoscopy). These endoscopic procedures are accompanied by the appropriate biopsies of the primary cancer and its margins. The skin and subcutaneous tissue overlying and in the vicinity of the primary cancer must be examined to exclude malignant invasion or severe radiation damage if previously administered.

The reconstruction must be planned and prospective organs of replacement/reconstruction evaluated. Vascular insufficiency secondary to smoking accelerated atherosclerosis may necessitate angiographic assessment of these organs and tissues. Gastroscopy and colonoscopy are essential to exclude intrinsic disease if the stomach or colon is being contemplated for replacement. The tissue planned for pedicle or free flaps must be assessed and alternatives considered and evaluated. A mediastinal tracheostomy may be necessary for reconstruction if there is significant length of tracheal involvement. This may require division of the innominate artery to avoid postoperative arterial erosion and ensuing hemorrhagic complications. Therefore, angiographic assessment of cerebral blood supply and patency of the Circle of Willis is compulsory if mediastinal tracheostomy and innominate artery division are planned.

As in all patients undergoing airway and esophageal surgery, cardiopulmonary assessment is essential. Comorbidities must be evaluated and the affected organ systems optimized preoperatively. During this time, the nutritional status and fitness of the patient is maximized.

Preparation and Positioning

The patient is positioned supine. Arterial line, oxygen saturation probe, and venous catheter placements are guided by the possibility of division of the innominate artery and sacrifice of the left innominate vein. Similarly EKG pad placement may be affected by resection of the primary cancer or harvesting of reconstructive flaps. EEG leads may be placed for monitoring if there is concern of compromising cerebral perfusion. Techniques and equipment necessary for endotracheal intubation will be determined by the primary cancer and presence of an established tracheostomy. Provisions must be made for cross-table ventilation during surgery.

The operative field is prepared and draped from patient's chin to suprapubic abdomen and bilaterally to midaxillary lines. The thigh and forearm/arm may be included in the field if they will be used for flap harvesting or skin grafting.

Exploration

The operation starts with a collar incision placed above the sternal notch. The incision should be positioned to permit extension laterally, if necessary, over the clavicles and inferior over the manubrium (Fig. 66-1). If a tracheostomy exists, the stoma should be included in the incision. Invaded or radiation-damaged skin is excluded from the flaps, excised, and left attached to the cancer. The superior subcutaneous flap is raised above the hyoid bone, and the inferior flap is lifted to the sternal notch. Cranial, caudal, lateral, and deep invasion are assessed during this mobilization. If uninvolved the strap muscles are then separated in the midline or if invaded they are divided and left attached to the primary cancer. Lateral dissection determines if the carotid sheath is involved by the cancer. The prevertebral space is developed to assure the resection can be completed posteriorly. These steps confirm cancer resectability and to this point no irreversible steps have been taken.

Resection

Typically, the resection begins inferiorly. If a mediastinal tracheostomy is necessary, the incision is extended in the midline inferiorly over the manubrium. The lateral myocutaneous flaps are raised off the bony chest wall, and the manubrium is excised along with the first and second cartilages and the clavicular heads (breast-plate). The level of tracheal division is selected. The trachea is circumferentially mobilized at this site and lateral dissection restricted below this point. Lateral traction sutures are placed in the tracheal wall one cartilage below the anticipated position of tracheal transection (Fig. 66-2). This will stabilize the trachea and facilitate tracheal intubation during cross-field ventilation. Once the trachea has been divided and distal intubation obtained, the tracheal margin is sent for frozen-section analysis. Some thyroid and airway (adenoid cystic carcinoma) cancers may not involve or minimally invade the esophagus, permitting esophageal preservation without compromising the resection. In patients requiring cervical exenteration the point of esophageal transection is determined. The extent of the primary cancer and the method and organ of esophageal reconstruction will dictate this level. If free flap is being used for reconstruction, the esophagus is divided in the low neck and this margin is sent for frozen-section analysis.

The dissection proceeds superiorly. The prevertebral plane, already assessed, is now easily developed. Laterally the dissection is carried along the carotid sheaths. Rarely unilateral sacrifice of the internal jugular vein is required. If unilateral carotid excision is required, arterial reconstruction or bypass will be necessary. If the thyroid is not involved, the isthmus is split and one or both sides are preserved and allowed to remain in the lateral resection margins. If not radiated this practice preserves thyroid and parathyroid function. If possible resected parathyroid tissue that is uninvolved with the primary cancer may be autotransplanted and this position marked with radiopaque clips.

The superior margin of the resection is now defined. The superior border of the hyoid bone is cleared of the attachments of the mylohyoid, geniohyoid, and genioglossus muscles. Lateral muscular attachments of the larynx are divided and the superior laryngeal neurovascular bundle controlled and divided (Fig. 66-3). The pharynx is entered anteriorly and the superior resection proceeds posteriorly. The epiglottis is incorporated in the resection specimen. The superior resection margin is sent for frozen-section analysis.

Reconstruction

The two main methods of pharyngoesophageal reconstruction involve either GI transposition (stomach or colon) or microvascular free flaps (jejunum or myocutaneous). The general approach is to use gastric or colonic transposition for cancers that extend to or below the thoracic inlet and free flaps for the short-length reconstruction required by cancers arising above the thoracic inlet.^2–4 However, in any one institution the experience may be so small that one of these methods may become the reconstruction of choice.

If division of the trachea is well above the sternal notch, a cervical tracheostomy stoma can be constructed. However, if tracheal division is at or below the sternal notch or if the operation is performed for tracheal stomal recurrence, a mediastinal tracheostomy will be necessary.^5,6 The anterior breast-plate is excised. Erosion of the innominate artery, a major complication of mediastinal tracheostomy, can be avoided by separating the tracheal stoma from the innominate artery. If the stoma will be positioned immediately adjacent to the artery, elective division and oversewing of the ends under EEG monitoring has been reported.⁷ However, transposing the trachea below and to the right of the innominate artery also has been successfully used to avoid this dreaded complication.⁸ Division of the innominate artery must be placed proximal to the carotid-subclavian bifurcation.

The omentum can be used to cover anastomoses, separate innominate artery stumps from the trachea, and tracheal wrapping below the stoma.⁹ If there is significant soft tissue resection and wound closure is problematic a benefit of using myocutaneous free flaps is the ability to reconstruct both GI and soft tissue defects with the flap.^10–12

ICU care is mandatory in the initial postoperative management of cervical exenteration patients. Mechanical ventilation is usually required. A customized tracheostomy tube may be necessary for the shortened trachea in patients requiring mediastinal tracheostomy. Trauma to the tracheal stoma should be avoided by careful and secure stabilization of the tracheostomy tube. A low-pressure tracheostomy cuff will protect the edematous and potentially ischemic trachea from necrosis and stricture. Adequate humidification of inspired air/oxygen mixture is important in minimizing pulmonary complications. Vigorous chest physiotherapy and careful pulmonary/tracheostomy care are the major foci of early postoperative care. An NG tube is necessary in patient with gastric reconstruction of the pharyngoesophagus segment, because they are very susceptible to regurgitation. Upright patient positioning is also critical in minimizing aspiration. Nutrition is provided via feeding tubes or parenterally until GI function returns and the pharyngoesophageal replacement has healed. Regardless of parathyroid preservation during resection, careful monitoring of serum calcium and prompt management of postoperative hypocalcemia is required in all patients. The need for long-term thyroid hormone replacement should be assessed.

A common site of complications specific to cervical exenteration is at the GI anastomoses. Varying degrees of anastomotic disruption can occur. This may be as simple as a transient anastomotic leak that can be managed by keeping the patient NPO, providing enteral or parenteral nutrition and locally draining the area. In the extreme there may be graft necrosis necessitating removal of the reconstruction, creating a pharyngostomy, oversewing of the distal GI tract, and constructing a feeding gastrostomy or jejunostomy. Anastomotic strictures are usually managed by repeated dilation. Universally, patients with gastric reconstruction are subject to regurgitation with coughing, reclining, or bending over. This is the result of sacrifice of the upper esophageal sphincter and the high pharyngeal location of the anastomosis. With time and specific maneuvers, such as limiting the size of meals and remaining upright for 2 to 3 hours after eating, this problem can be tolerated. However, this predictable functional disorder has led some to favor the colon over the stomach for GI reconstruction after cervical exenteration.

Tracheocutaneous stomal separation is usually treated conservatively, responding to debridement. Stomal stenosis can be managed with long-term placement of an indwelling tracheostomy tube. Recalcitrant stenosis will require revision of the tracheostomy and possibly conversion of a low cervical tracheostomy to a mediastinal tracheostomy. Vascular complications are common to mediastinal tracheostomy unless the steps mentioned earlier are not taken to separate the stoma from the innominate artery. Cerebrovascular accident not necessarily related to innominate artery division can complicate this extensive resection.

Chylous leakage may complicate extensive dissection about the left subclavian-internal jugular veins. Conservative management using parenteral nutrition and local drainage may not be successful because of the exenteration. Octreotide administration may hasten the resolution of chylous complications. Reexploration with direct ligation of the lymphatic injury or thoracotomy with ligation of the thoracic duct has been used. However, there is increasing experience and use of lymphangiography and x-ray–guided percutaneous embolization of the thoracic duct.

Hepatic failure has complicated the postoperative course of patients with squamous cell carcinoma undergoing cervical exenteration. Alcohol abuse, a factor in development of these cancers, may cause clinically unsuspected cirrhosis that is uncovered in the recovery from this extensive surgery. Pulmonary complications are a common problem in the postoperative course of these patients.

Long-term survival is determined by the underlying cancer.

Cancers of the upper aerodigestive tract may on rare occasion require resection, typically for salvage following failed primary treatment or long-term palliation. Clinical staging, preoperative evaluation, and operative exploration determine resectability. An en bloc pharyngo-laryngo-tracheo-esophagectomy necessitates (1) reconstruction of the pharynx and esophagus, using gastric or colonic transposition for cancers that extend to or below the thoracic inlet and free flaps for the short-length reconstructions of cancers confined to the neck and (2) a permanent end tracheostomy. Specific complications include (1) varying degrees of GI anastomotic disruption and (2) hemorrhage common to mediastinal tracheostomy unless the steps are not taken to separate the tracheal stoma from the innominate artery. Long-term survival following cervical exenteration is determined by the underlying cancer.

A 65-year-old male, who is a retired army veteran, presented with solid dysphagia and a lump in his left neck. He was found to have a cT4aN1M0 squamous cell carcinoma of the hypopharynx with invasion of the esophagus and a single 2-cm ipsilateral regional nodal metastasis. Prior to therapy, he stopped smoking and reduced his drinking to two glasses of beer a day. He received definitive chemoradiotherapy, three courses of 5-FU (1000 mg/m² per day for 4 days) and cisplatin (100 mg/m²), and concurrent external-beam radiation (60 Gy). His posttreatment course was complicated by dysphagia which responded to two sessions of guided esophageal dilation. He did well for 14 months, but again experienced difficulty swallowing solids and new onset of hoarseness. He was found to have recurrence of squamous cell carcinoma in the anterior wall of the hypopharynx with extension into the cervical esophagus. This was staged as ycT3N0M0.

Clinical examination and imaging suggested this was a local recurrence. He underwent a pharyngo-laryngo-tracheo-esophagectomy (Fig. 66-4). A total esophagectomy was necessary because of involvement of the cervical esophagus and an associated radiation stricture. A pharyngogastric anastomosis was constructed with a single-layer interrupted absorbable suture. The tracheostomy was placed low in his neck just above the sternal notch. An omentum graft was brought substernally to cover the pharyngoesophageal reconstruction and wrap the trachea at the stoma. His postoperative course was complicated by respiratory compromise and a pharyngocutaneous anastomotic fistula. Vigorous chest physiotherapy, frequent suctioning, broad-spectrum antibiotics, meticulous care of his tracheostomy stoma and 3 weeks of mechanical ventilation were necessary for successful treatment of his postoperative pneumonia. Local drainage of the fistula, NG-tube drainage of his stomach, and nutritional support via his j-tube successfully closed the anastomotic fistula in 4 months.

Four years after cervical exenteration, he was swallowing well. His tracheostomy stoma was well healed and required only daily tracheostomy care. By physical examination there was no local recurrence of his hypopharyngeal carcinoma. Imaging was proposed at 6-month intervals; however, the scans in the third postoperative year were missed. He was found to have a 2-cm spiculated mass in the upper lobe of his right lung at his fourth year annual CT scan. This was hypermetabolic on FDG-PET examination (SUV 7.3) with no evidence of regional lymph node enlargement or hypermetabolism. FNA proved this to be a squamous cell carcinoma. He received radiosurgery for this presumed cT1aN0M0 metachronous primary squamous cell carcinoma of the lung. After this therapy, 6 years following cervical exenteration, he has remained free of recurrent or metachronous squamous cell cancer.

Mediastinal exenteration is a formidable operation which is not commonly performed. It is usually performed after failure of chemoradiation making the operation more complex. We often collaborate with an otolaryngologist in this type of procedure to maximize patient benefit. Stomach or colon should usually reach high up, but sometimes, a free flap of jejunum can be used to extend the conduit.