Each year, 11,000 new cases of larynx cancer will be diagnosed in the United States (1% of new cancer diagnoses), and approximately one-third of these patients will die of their disease. The current male-to-female ratio for larynx cancer is 4:1, but the relative percentage of women with this, as with other smoking-related illness, has been on the rise. Larynx cancer is most prevalent in the sixth and seventh decades of life and is more prevalent among lower socioeconomic groups, for whom it is often not diagnosed until more advanced stages. More than 90% of larynx cancer is squamous cell carcinoma (SCC) and is directly linked to tobacco and excessive alcohol use. Because of the complex and multifaceted nature of this disease, treatment planning is best delivered through a multidisciplinary tumor board format.
The larynx functions not only to produce voice but also to divide and protect the respiratory tract from the digestive tract. It acts as a sphincter during deglutition, protecting against the penetration of bypassing food by closing off the trachea at two sites: the epiglottic flap and the closure of the vocal cords. The larynx consists of a framework of cartilages connected by ligaments, membranes, and muscles covered by a respiratory and stratified squamous mucosal epithelium (Figure 31–1).
Cartilages and ligaments of the larynx. (A) Frontal view and (B) posterior view. (Adapted, with permission, from Hollinshead WH. Anatomy for Surgeons: The Head and Neck, 3rd ed. JB Lippincott, 1982.)
The larynx can be divided into three parts: the supraglottis, the glottis, and the subglottis (Figure 31–2). The supraglottic larynx extends from the tip of the epiglottis and vallecula superiorly to the ventricle and undersurface of the “false” cords inferiorly; it includes the arytenoid cartilages, the aryepiglottic folds, the false vocal cords, and the epiglottis. The glottic larynx encompasses the “true” vocal cords, extending from the ventricle between the true and false cords to 0.5 cm below the free edge of the true cords, including the anterior commissure and interarytenoid area. The subglottic larynx extends from the inferior extent of the glottis to the inferior edge of the cricoid cartilage.
The supraglottic, glottic, and subglottic anatomic subdivisions of the larynx. (Adapted, with permission, from Bailey BJ (ed): Head and Neck Surgery—Otolaryngology, 3rd ed. Lippincott Williams & Wilkins, 2001.)
Understanding the embryologic origin of these regions of the larynx helps to explain the difference in clinical behavior between cancers arising from these laryngeal subsites. The supraglottis derives from the midline buccopharyngeal primordium and branchial arches 3 and 4 with rich bilateral lymphatics. The glottis, on the other hand, forms from the midline fusion of lateral structures derived from the tracheobronchial primordium and arches 4, 5, and 6. There is a paucity of ...