TNM Staging Guide 5th Edition eBook

chain lymph nodes (Levels II and III), but can also spread to retropharyngeal lymph nodes, which distinguishes them from oral cavity tumors and must be considered when treating oropharyngeal cancers. While traditional risk factors for oropharyngeal cancers are tobacco and alcohol use, there has been a near epidemic rise in the incidence of oropha- ryngeal cancer related to human papillomavirus (HPV) infection. These HPV-related tumors most often occur in younger patients who may lack exposure to other carcinogens, resulting in a more homogenous tumor population with fewer genetic abnormalities. This lack of genetic heterogene- ity appears to lead to better responsiveness to treatment and significantly higher cure rate. Tumors in the oropharynx can be managed in two ways. Early stage disease can be managed with definitive radiation therapy or surgery. When surgery is employed, the primary tumor is typically resected using a transoral approach (either with transoral robotic surgery or transoral laser microsurgery) and the involved and at-risk lymphatics are addressed through a neck dissection. For advanced disease, combination therapy is typically employed. This can be in the form of upfront surgery with adjuvant radiation or chemoradiation therapy, or definitive chemoradiation therapy, using surgery for salvage. In such instances, the approach should be tailored to the individual patient and tumor characteris- tics to optimize disease control and minimize the morbidity of treatment. Due to the excellent response rates of HPV-related oropharyngeal cancers, trials are on-going to evaluate the safety and efficacy of de-intensified treatment protocols. The goals of these initiatives are to maintain similar levels of oncologic control while decreasing the associated side effects. LARYNX The larynx is the most complex of the mucosal lined structures of the UADT. The important roles of the larynx in speech, swallowing, and airway protec- tion make the treatment considerations of cancers of this structure varied and controversial. The larynx is bordered by the oropharynx superiorly, the trachea inferiorly, and the hypopharynx laterally and posteriorly. The larynx is comprised of a cartilaginous framework, and is subdivided vertically by the vocal folds into the supraglottic, glottic, and subglottic subsites. The supra- glottic larynx includes the epiglottis, which has both lingual and laryngeal surfaces, the false vocal cords, the arytenoids cartilages, and the aryepiglottic

4 TNM Staging of Head and Neck Cancer and Neck Dissection Classification