1 BACKGROUND General • Head and neck cancers are the sixth most common cancers among males and twice in prevalence when compared with females. 1 • Head and neck cancers are composed of cancers arising from the paranasal sinuses, nasopharynx, oral cavity, oropharynx, hypopharynx, and larynx. 2 The cancers arising from the salivary glands and lip are not reviewed in this chapter. • The following are the main risk factors 3–5 : • Tobacco and alcohol use. • Infection with human papillomavirus (HPV), particularly HPV-16 infection, is one of the main causes of oropharyngeal cancers. • No screening test is available for head and neck can- cers. 6 • The hypopharyngeal, laryngeal, oropharyngeal, and nasopharyngeal cancers present with distant metasta- ses in 19%, 16%, 13%, and 10% of cases, respectively. 7 • Cervical lymph node metastasis is the presenting sign in about 2% to 9% of patients with head and neck squamous cell carcinoma (HNSCC) with an unknown primary site of cancer. 8 Early Clinical Symptoms 9 • Cervical lymphadenopathy • Long-lasting oral cavity ulcer or sore throat • Dysphagia • Hoarseness • Nasal airway obstruction Standard Diagnostic Procedures 10 • Clinical examination • Panendoscopy and biopsy • Fine-needle aspiration or core biopsy • CT, MRI, and PET/CT (if indicated) • HPV diagnostics Standard Treatment 11–13 • Surgery • Radiation therapy • Chemotherapy • Targeted therapy Prognostic Factors 13–15 • Tumor location (worse in hypopharyngeal cancers) • Tumor size (worse if larger) • Lymph node status (worse if contralateral neck nodes are involved) • Histologic grade (worse if high grade/poorly differ- entiated) • Overexpression of epidermal growth factor receptor (worse prognosis) • Tumors not associated with HPV (worse prognosis) Five-Year Survival 16 • Stage I: 77% • Stage II: 61% • Stage III: 57% • Stage IV: 42% TUMOR CHARACTERISTICS AND TYPICAL BEHAVIOR Histopathology 2,17 • Squamous cell carcinoma: >90% • Others (adenocarcinoma, esthesioneuroblasto- ma, lymphoepithelioma, adenoid cystic cancer): <10% Distribution and Localization T-primary 2,18 • Paranasal sinuses • Nasopharynx • Oral cavity • Oropharynx • Hypopharynx • Larynx N-lymph nodes 2 The primary localization of the lymph nodes and their cervical level are provided in Table 1.1. CHAPTER 1 Head and Neck Cancers MOHSEN BEHESHTI • RATHAN M. SUBRAMANIAM • ALIREZA REZAEE • MARTIN BURIAN • WERNER LANGSTEGER