General Medical Information

Cervical Esophageal Cancer

ANATOMY
The cervical esophagus is that area of the esophagus situated superior to the manubrium. The superior margin is the cricopharyngeus muscle, and its inferior limit is the suprasternal notch. The precise length of the cervical esophagus varies; some patients with severe kyphosis may have little or no esophagus superior to the sternum.

The esophagus is covered throughout by a layer of stratified squamous epithelium. Beneath the mucosa is a submucosal or areolar layer, then a muscular layer composed of an external longitudinal and an internal circular layer. In the cervical esophagus, this muscular layer is striated muscle (in contrast to the lower esophagus, which is largely smooth muscle). The arterial supply of the cervical esophagus is derived from the thyroid branch of the thyrocervical trunk; the venous drainage is to the inferior thyroid vein. The nervous supply is derived from the vagus nerve via the recurrent laryngeal nerve and from the sympathetic trunks. The parasympathetic and sympathetic fibers form plexuses between the layers of the muscular coat, which serve to mediate peristalsis.

The lymphatic drainage of the cervical esophagus goes to the paratracheal nodes, from where they may pass either superiorly to join the lymphatics of the pharynx and terminate in the internal jugular chain of nodes or drain inferiorly into the superior mediastinum.

PHYSIOLOGY
The function of the cervical esophagus is active participation in swallowing. The cricopharyngeus muscle, located at the superior aspect of the cervical esophagus, serves as the upper esophageal sphincter. Coordinated reflex relaxation of the cricopharyngeal muscle is critical to the normal physiology of swallowing. Dilatation of the cricopharyngeus results in initiation of the esophageal peristaltic wave. Normal resting tone of the cricopharyngeus serves to prevent or reduce reflux of esophageal contents into the hypopharynx.

EPIDEMIOLOGY
Carcinoma of the esophagus accounts for less than 1% of newly diagnosed malignancies in the United States each year, but the incidence varies greatly around the world. Approximately 12,000 new cases are diagnosed annually; 11,000 deaths are attributed to esophageal cancer. Cancer of the cervical esophagus is only a fraction of this total. Cancer of the esophagus is 80 times more common in the Middle East, southern and eastern Africa, and northern China. The use of alcohol and tobacco has a clear-cut etiologic relationship to the risk of esophageal carcinoma. In one study the risk for a heavy smoker was 4.5 times that of a non-smoker, non-drinker, while that of the heavy drinker was 11 times the risk. The apparent synergy between the use of tobacco and alcohol is demonstrated by the fact that the risk in people who both smoke and drink heavily is over 100 times. Some studies have suggested that nitrosamines may be associated with increased risk of carcinoma of the esophagus.

Most tumors involving the cervical esophagus either extend distally into the thoracic esophagus or originate in the hypopharynx with extension into the cervical esophagus. Carcinoma limited to the cervical esophagus is rare. Diagnostic maneuvers must be aimed at identifying the full extent of tumor involvement so that therapeutic planning and reconstruction, when excision is appropriate, can be appropriately coordinated.

The tumor most commonly encountered in the cervical esophagus is squamous cell carcinoma. Adenocarcinoma may occasionally be encountered in the esophagus, but it arises either from gastric mucosa found near the gastroesophageal junction or in mucous glands embedded in the epithelium of the esophagus. Barrett esophagus (the columnar epithelium associated with long-standing reflux esophagitis) has been associated with adenocarcinoma. An estimated 5% of people with gastroesophageal reflux may develop Barrett esophagus, and 5% of that group may develop a malignancy. Tylosis, an autosomal-dominant trait in which marked thickening of the palms and soles occurs, has been associated with a high risk of developing esophageal carcinoma by age 65. Similarly, patients with a history of head and neck cancer or achalasia have an increased incidence of carcinoma of the esophagus.

A patient with cervical esophageal cancer has an increased risk of developing a second primary carcinoma in either the lung or upper aerodigestive tract. Similarly, development of an esophageal carcinoma has been widely reported in a significant percentage of patients with a primary tumor on another mucosal site in the head and neck.