Cancer of the Hypopharynx, Larynx, and Esophagus

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Describe the general anatomic divisions of the larynx.

Vertically, the larynx is subdivided into three regions: the supraglottis, the glottis, and the subglottis. The division of these three subsites reflects embryologic development and natural barriers to cancer spread.

The supraglottis can be thought of as a three-dimensional box containing a suprahyoid and infrahyoid epiglottis, the aryepiglottic folds, arytenoids, ventricles, and false vocal folds. It extends from the superior surface of the epiglottis and the superior edge of the aryepiglottic folds to a horizontal plane passing through the lateral margin of the ventricle and the superior surface of the true vocal folds. The supraglottis has bilateral lymphatic drainage to the upper and middle jugular lymph nodes.

The glottis begins at the superior surface of the true vocal fold and extends inferiorly 1 centimeter. Laterally, it is bordered by the thyroid cartilage with the lateral ventricle coming to the superior most extent. It contains the anterior and posterior commissures. The vocal folds themselves have sparse lymphatics; therefore deep invasion is needed for unilateral lymphatic spread.

The subglottis begins at the inferior border of the glottis (1 centimeter below the supraglottis) and proceeds to the inferior border of the cricoid cartilage.

2

Regarding the divisions of the larynx, where does laryngeal cancer commonly occur?

Laryngeal cancer most commonly arises in the glottis (60%), followed by the supraglottis (35%) and subglottis (2%); another 3% are transglottic and involve multiple subsites. An overwhelming 95% of glottic cancers arise from the true vocal cords. Because of natural barriers to spread and early presenting symptoms, laryngeal cancer is often confined to the larynx at time of diagnosis (60% of cases).

3

How common is laryngeal cancer?

Laryngeal cancer is the second most common malignancy of the head and neck (after oral cavity/oropharynx). Currently, in the United States, there are over 12,000 new cases of laryngeal cancer annually. One-third of these patients will die from their disease. The number of new cases is declining by roughly 2% to 3% per year due to decreased smoking. Laryngeal cancer is 3.8 times more common in men than women, though the gender disparity has narrowed in recent years due to the increased proportion of female smokers.

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What are the risk factors for laryngeal cancer?

Tobacco and alcohol are the primary risk factors for laryngeal cancer. The risk is thought to be directly proportional to the duration and intensity of exposure. Smoking and alcohol are synergistic in increasing cancer risk rather than merely additive. Risk does decrease slowly after cessation but does not return to baseline for at least 20 years. Patients who continue to smoke through out their treatment are at a higher risk of recurrence and development of a second primary. There are conflicting data as to whether laryngopharyngeal reflux could be a risk factor. One meta-analysis has shown an increased risk in patients with confirmed gastroesophageal reflux disease. Human papillomavirus has not definitively been shown to be a cause of laryngeal cancer.

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What types of cancers are found in the larynx?

Squamous cell carcinoma (SCC) is the most common type of malignancy found in the larynx, accounting for more than 95% of all tumors. Variations of SCC include verrucous carcinoma (2% to 4%) and spindle cell carcinoma. Verrucous carcinoma carries an improved prognosis, while spindle cell variants are more aggressive. Both subtypes are typically treated with surgical excision.

Less common nonepithelial tumors include adenoid cystic carcinoma, mucoepidermoid carcinoma, sarcoma (e.g., fibrosarcoma, chondrosarcoma, liposarcoma), neuroendocrine tumor (e.g., paragangliomas, carcinoid), contiguous lesions (i.e., thyroid), and metastatic lesions.

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How might a patient with laryngeal cancer present?

Hoarseness, dysphagia, odynophagia, referred otalgia, globus sensation, weight loss, and neck mass can all be presenting symptoms. Glottic cancers tend to present early with hoarseness, whereas airway obstruction and hemoptysis are later findings. Supraglottic cancers often present with dysphagia and odynophagia. Otalgia can occur due to pharyngeal extension. Hoarseness occurs secondary to transglottic extension or arytenoid involvement. Airway obstruction can be gradual with bulky disease or may be acute in onset from a ball–valve type of obstruction. Supraglottic tumors are usually discovered later and have a poorer prognosis as these symptoms arise with progression beyond the supraglottis. Subglottic carcinomas present with signs and symptoms of early airway obstruction such as biphasic stridor.

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