Head and neck cancers encompass a diverse group of malignancies arising from the mucosal surfaces of the oral cavity, oropharynx, larynx, hypopharynx, nasopharynx, and paranasal sinuses. The American Cancer Society estimates approximately 71,100 new cases of head and neck cancer are diagnosed in the United States each year, with roughly 16,000 deaths. Globally, head and neck squamous cell carcinoma (HNSCC) is the sixth most common cancer, with over 900,000 new cases annually (GLOBOCAN).
The epidemiology of head and neck cancer has shifted dramatically in recent decades. While tobacco and alcohol remain the dominant risk factors for oral cavity, laryngeal, and hypopharyngeal cancers, human papillomavirus (HPV) infection—particularly HPV type 16—has emerged as the primary driver of oropharyngeal cancer in developed countries. HPV-positive oropharyngeal cancers have substantially better prognosis than their HPV-negative counterparts, and ongoing research is evaluating treatment de-escalation strategies for this favorable-prognosis group.
Anatomic Sites
Oral Cavity
Includes the lips, floor of mouth, anterior two-thirds of the tongue, buccal mucosa, gingiva, hard palate, and retromolar trigone. Oral cavity cancers are predominantly squamous cell carcinomas and are strongly associated with tobacco use (smoking and smokeless), alcohol consumption, and betel nut chewing (particularly in South and Southeast Asia). Surgery is typically the primary treatment, with adjuvant radiation ± chemotherapy for advanced or high-risk features.
Oropharynx
Includes the base of tongue, palatine tonsils, soft palate, and posterior pharyngeal wall. Oropharyngeal cancer is the site most strongly associated with HPV infection. HPV-positive oropharyngeal cancers typically present in younger, non-smoking patients with cystic cervical lymph node metastases. The AJCC 8th Edition introduced a separate staging system for HPV-positive (p16-positive) oropharyngeal cancer, reflecting its significantly better prognosis. Primary treatment may be surgery (transoral robotic surgery, TORS) or definitive radiation with concurrent chemotherapy.
Larynx
Laryngeal cancer arises from the glottis (vocal cords, most common), supraglottis (above the vocal cords), or subglottis (below the vocal cords). Glottic cancers tend to present early with hoarseness and have a favorable prognosis. Laryngeal preservation using concurrent chemoradiation (cisplatin + radiation) is the standard approach for locally advanced laryngeal cancer, based on the landmark VA Laryngeal Cancer Study and RTOG 91-11 trial, which demonstrated equivalent survival to total laryngectomy with organ preservation in most patients.
Hypopharynx
Includes the pyriform sinuses, posterior pharyngeal wall, and postcricoid region. Hypopharyngeal cancers are strongly associated with heavy tobacco and alcohol use and frequently present at an advanced stage due to the paucity of early symptoms. Prognosis is generally the poorest among head and neck subsites, with five-year survival rates of approximately 30–35% for all stages combined. Concurrent chemoradiation is the preferred treatment for organ preservation.
Nasopharynx
Nasopharyngeal carcinoma (NPC) is unique among head and neck cancers in its epidemiology, biology, and treatment. It is endemic in southern China and Southeast Asia, with a strong association with Epstein-Barr virus (EBV). NPC is classified into three WHO subtypes: keratinizing squamous cell carcinoma (type I), non-keratinizing differentiated (type II), and non-keratinizing undifferentiated (type III, the most common and most EBV-associated). NPC is highly sensitive to radiation and chemotherapy. The standard treatment for locoregionally advanced NPC is concurrent cisplatin-based chemoradiation, with five-year survival rates of approximately 70–80%. Plasma EBV DNA is a valuable biomarker for monitoring treatment response and detecting recurrence.
HPV-Positive vs HPV-Negative Oropharyngeal Cancer
| Feature | HPV-Positive | HPV-Negative |
|---|---|---|
| Primary risk factor | HPV-16 infection (sexual transmission) | Tobacco and alcohol use |
| Typical patient | Younger (40–60), non-smoker or light smoker | Older (55+), heavy tobacco/alcohol history |
| Presentation | Cystic neck mass, small or occult primary | Symptomatic primary tumor (pain, dysphagia) |
| 3-year overall survival | ~82–85% | ~55–60% |
| Treatment response | Excellent response to radiation and chemotherapy | Less favorable, higher recurrence rates |
HPV status (determined by p16 immunohistochemistry) is the most important prognostic factor for oropharyngeal cancer. Source: NCI, ASCO, AJCC 8th Edition.
Risk Factors
- Tobacco use — The strongest risk factor for HPV-negative head and neck cancer. Cigarette, cigar, pipe smoking and smokeless tobacco all increase risk. The risk increases with quantity and duration of use.
- Alcohol consumption — Heavy alcohol use is an independent risk factor and has a multiplicative (synergistic) effect when combined with tobacco. The combination of heavy smoking and heavy drinking increases HNSCC risk by 15–30 fold compared to neither exposure.
- HPV infection — HPV-16 is the primary cause of HPV-positive oropharyngeal cancer. Sexual behavior (number of oral sex partners) is the primary risk factor for oral HPV infection.
- Epstein-Barr virus (EBV) — Strongly associated with nasopharyngeal carcinoma, particularly in endemic regions.
- Betel nut (areca nut) chewing — A major risk factor for oral cavity cancer in South and Southeast Asia.
- Occupational exposures — Wood dust (sinonasal cancer), nickel, formaldehyde, and asbestos.
- Poor oral hygiene and dental health — Associated with increased oral cavity cancer risk.
Salivary Gland Tumors
Salivary gland cancers are uncommon, representing approximately 3–5% of head and neck cancers. The parotid gland is the most common site. Types include mucoepidermoid carcinoma (most common malignant salivary tumor), adenoid cystic carcinoma (known for perineural invasion and late distant recurrence), and acinic cell carcinoma. Surgery is the primary treatment, with adjuvant radiation for high-grade or advanced tumors.
Staging (AJCC 8th Edition)
Head and neck cancers are staged using the TNM system, with separate staging criteria for each anatomic site. The AJCC 8th Edition introduced a distinct staging system for HPV-positive (p16+) oropharyngeal cancer, with higher stage groupings required for equivalent stage assignment, reflecting the markedly better prognosis. For example, extensive nodal disease that would be classified as Stage IVA in HPV-negative cancer is classified as Stage I or II in HPV-positive disease. Staging relies on clinical examination, cross-sectional imaging (CT with contrast, MRI), PET-CT for advanced disease, and endoscopic evaluation under anesthesia.
Treatment Options
Surgery
Surgical approaches vary by site and extent of disease:
- Transoral robotic surgery (TORS) — Minimally invasive surgery for oropharyngeal cancers, providing excellent oncologic outcomes with reduced morbidity compared to open surgery. The ORATOR trial and other studies have established TORS as a primary treatment option.
- Transoral laser microsurgery (TLM) — Used for early glottic cancers with excellent voice outcomes and cure rates comparable to radiation.
- Open surgical resection — Composite resection with free flap reconstruction for advanced oral cavity cancers. Neck dissection is performed for clinically involved or high-risk cervical lymph nodes.
- Total laryngectomy — Reserved for very advanced laryngeal/hypopharyngeal cancers, laryngeal dysfunction after chemoradiation, or salvage after radiation failure. Tracheoesophageal puncture (TEP) voice prosthesis enables speech rehabilitation.
Radiation Therapy
Definitive radiation therapy (with or without concurrent chemotherapy) is a primary treatment modality for many head and neck cancers, particularly those of the oropharynx, nasopharynx, and larynx where organ preservation is desired. Intensity-modulated radiation therapy (IMRT) is standard, as it significantly reduces xerostomia (dry mouth) by sparing the parotid glands. Proton beam therapy is under investigation for further reduction of late toxicities. A standard definitive radiation course delivers approximately 70 Gy in 35 fractions over 7 weeks to gross disease, with lower doses to elective nodal regions.
Systemic Therapy
- Cisplatin — High-dose cisplatin (100 mg/m² every 3 weeks) concurrent with radiation is the standard radiosensitizing regimen for locally advanced HNSCC. The addition of cisplatin to radiation improves overall survival by approximately 6–8%.
- Cetuximab (Erbitux) — Anti-EGFR monoclonal antibody approved concurrent with radiation for locally advanced HNSCC. However, the RTOG 1016 and De-ESCALaTE trials demonstrated that cetuximab is inferior to cisplatin for HPV-positive oropharyngeal cancer, establishing cisplatin as the preferred concurrent agent.
- Pembrolizumab (Keytruda) — Approved as first-line treatment for recurrent/metastatic HNSCC, alone (for PD-L1 CPS ≥1) or with platinum/5-FU chemotherapy (KEYNOTE-048 trial). Has become the new standard of care for recurrent/metastatic disease.
- Nivolumab (Opdivo) — Approved for recurrent/metastatic HNSCC after platinum-based chemotherapy (CheckMate-141 trial).
Induction Chemotherapy
The role of induction (neoadjuvant) chemotherapy before definitive local treatment remains debated. The TPF regimen (docetaxel, cisplatin, 5-fluorouracil) has shown tumor shrinkage and organ preservation benefits in some settings, particularly for laryngeal and hypopharyngeal cancers. However, multiple randomized trials (PARADIGM, DeCIDE) have failed to demonstrate a clear overall survival benefit for adding induction chemotherapy to concurrent chemoradiation. Induction chemotherapy may be considered for select patients with bulky, symptomatic disease requiring rapid tumor shrinkage or for risk-stratification in clinical trial settings.
Salvage Surgery
Patients who develop local or regional recurrence after primary radiation or chemoradiation may be candidates for salvage surgery, which offers the best chance of cure for locoregional recurrence. Salvage surgery is technically more challenging due to radiation-induced tissue changes and carries higher complication rates, including wound healing problems and fistula formation. Free tissue transfer (microvascular free flaps) has significantly improved reconstructive outcomes after salvage resections.