Head and Neck Cancers

Modifiable — carcinogen exposure (field cancerization)

• Tobacco in all forms: cigarettes, cigars, pipes, and smokeless/chewing tobacco and snuff deliver nitrosamines and polycyclic aromatic hydrocarbons that form DNA adducts across the entire aerodigestive mucosa; risk is dose- and duration-dependent and declines but does not normalize after cessation. Smokeless tobacco classically produces buccal/gingivobuccal sulcus lesions at the site where the quid is held.
• Alcohol: acetaldehyde, the ethanol metabolite, is directly mutagenic and alcohol acts as a mucosal solvent enhancing penetration of tobacco carcinogens — the tobacco–alcohol combination is synergistic (multiplicative), not additive.
• Betel quid / areca nut (South and Southeast Asian populations): causes oral submucous fibrosis with trismus and is the classic setting for verrucous carcinoma.
• HPV (high-risk types 16, 18): sexually acquired oropharyngeal infection; the epidemiologic marker in the stem is a younger, non-smoking patient with a tonsil or base-of-tongue primary and cystic cervical nodes. ACIP/CDC recommend routine HPV vaccination at 11–12 years, catch-up through age 26, and shared clinical decision-making for ages 27–45.
• Occupational/environmental: the classic exposures are paired to distinct histologies — wood dust and leather dust → sinonasal adenocarcinoma (ethmoid/nasal cavity, furniture and shoemaking trades), whereas nickel compounds and chromium → sinonasal squamous cell carcinoma (nickel refining also raises lung cancer risk). Formaldehyde is an additional nasopharyngeal/sinonasal exposure, and chronic UV exposure causes lower lip vermilion SCC.
• Chronic irritation and poor dentition: ill-fitting dentures, sharp teeth, poor oral hygiene.

Non-modifiable and host factors

• EBV: latent infection is the driver of nasopharyngeal carcinoma, concentrated in southern Chinese and North African populations; salted-fish nitrosamine exposure in childhood is the co-factor. Plasma EBV DNA tracks disease burden.
• Genetic/syndromic susceptibility: Fanconi anemia and dyskeratosis congenita confer strikingly elevated risk of oral SCC at a young age without tobacco use.
• Iron-deficiency-associated Plummer-Vinson (Paterson-Brown-Kelly) syndrome: dysphagia, esophageal web, glossitis — predisposes to postcricoid hypopharyngeal SCC.
• Demographics: increasing age, male sex, and prior head/neck radiation.
• Immunosuppression: solid-organ transplant recipients and advanced HIV.

• Multistep carcinogenesis via field cancerization: Chronic tobacco and alcohol exposure causes widespread mutagenesis across the mucosa, leading to multiple independent primary tumors and recurrent cancers; this "field effect" explains the high risk of second primaries (4-5% annually)

• HPV-mediated transformation: High-risk HPV types integrate into the host genome, disrupting p53 and Rb tumor suppressor pathways through viral oncoproteins E6 and E7, leading to uncontrolled proliferation; HPV-associated cancers tend to originate in the oropharynx (particularly the base of tongue and tonsillar fossa) and carry a better prognosis than HPV-negative tumors

• Epithelial-to-mesenchymal transition (EMT): Progressive loss of cell-cell adhesion and acquisition of migratory properties facilitate lymph node metastasis, the most common site of spread; cervical lymph node involvement is present in ~40% at diagnosis

• Angiogenesis and hypoxia: Tumor-induced neovascularization and hypoxic microenvironment promote aggressive growth and treatment resistance

• Genetic alterations: Beyond p53 and Rb, mutations in CDKN2A (p16), PTEN, PIK3CA, and TP53 accumulate progressively; p16 overexpression correlates with HPV status and better prognosis

• Persistent oral/pharyngeal ulcer or mass (>2 weeks): Any non-healing ulcer or palpable mass in the oral cavity, tongue, or oropharynx; patients often notice a change in fit of dentures or difficulty wearing dentures

• Dysphagia and odynophagia: Difficulty or pain with swallowing, may progress to drooling, aspiration risk, and unintentional weight loss; suggests deeper infiltration or involvement of pharyngeal musculature

• Hoarseness or voice changes (>2 weeks): Persistent hoarseness warrants laryngoscopy to exclude laryngeal pathology; may indicate vocal cord involvement or recurrent laryngeal nerve invasion

• Otalgia (ear pain) with no otologic findings: Referred pain via trigeminal nerve (CN V) or glossopharyngeal nerve (CN IX) suggests oropharyngeal or nasopharyngeal involvement

• Cervical lymphadenopathy: Painless, hard, fixed cervical lymph nodes; may be the presenting symptom in up to 25% of cases ("neck mass as first presentation"); node levels are classified I-VI for surgical planning

• Trismus (limited mouth opening): Due to masseter involvement, suggesting advanced disease with poor prognosis

• Nasopharyngeal symptoms: Unilateral nasal obstruction, epistaxis, or otitis media with effusion from Eustachian tube obstruction (highly suggestive of nasopharyngeal cancer)

• Airway compromise: Stridor or breathing difficulty indicates advanced laryngeal involvement requiring urgent evaluation and possible tracheostomy

• Important clinical pearl: Absence of pain does NOT exclude cancer; many patients present late because early tumors may be asymptomatic

• Flexible fiberoptic laryngoscopy (gold standard for visualization): Direct visualization of the larynx, pharynx, and oral cavity; allows assessment of tumor size, location, and extent; enables biopsy under direct visualization

• Tissue biopsy and histology: Definitive diagnosis requires tissue confirmation; biopsy typically obtained during laryngoscopy; HPV testing (p16 immunohistochemistry or HPV DNA/RNA testing) should be performed on all oropharyngeal SCC to guide prognosis and treatment intensity

• TNM staging and imaging:
• CT with IV contrast (thin-section): Assesses bony invasion, cartilage involvement, and local-regional spread; primary modality for laryngeal and oral cavity cancers
• MRI: Superior soft tissue contrast; preferred for assessing perineural invasion, skull base invasion, and deep muscle involvement; excellent for nasopharyngeal and oropharyngeal cancers
• PET-CT: Standard for detecting distant metastases (most common site: lungs, then bone); improves detection of nodal involvement; recommended for stage III-IV disease
• Ultrasound with fine-needle aspiration (FNA): Useful for evaluating cervical nodes; FNA cytology or core biopsy for node characterization

• TNM staging (8th edition AJCC): T stage (tumor size/extent: T1-T4), N stage (nodal involvement: N0-N3), M stage (distant metastasis); HPV status dramatically changes prognosis—HPV-positive oropharyngeal cancers are staged one level lower than HPV-negative tumors

• Panendoscopy: Examination under general anesthesia of larynx, pharynx, esophagus, and bronchi to assess for synchronous second primaries (occurs in 3-10% of patients)

• Early-stage disease (Stage I-II):
• Single-modality therapy is standard: either radiation therapy (RT) alone (60-70 Gy over 6-7 weeks) or surgical resection alone (transoral robotic surgery [TORS] increasingly preferred for accessibility and functional preservation)
• TORS advantages: single procedure, shorter treatment course, better swallowing preservation compared to RT
• RT advantages: non-invasive, treats entire field including occult nodal disease
• Chemotherapy is NOT routinely used in early-stage disease

• Locally advanced disease (Stage III-IV) without distant metastases:
• Concurrent chemoradiation (CCRT) is standard of care: 70 Gy external beam RT with concurrent cisplatin 100 mg/m² IV every 3 weeks (3 cycles) or weekly cisplatin 40 mg/m²; provides superior locoregional control and 5-year OS compared to RT alone
• Alternative: Surgical resection followed by adjuvant RT ± chemotherapy if high-risk features (positive margins, extranodal extension, perineural invasion, lymphovascular invasion)
• HPV-positive oropharyngeal cancers: De-escalation strategies being investigated (reduced RT dose, reduced chemotherapy cycles) to minimize long-term toxicity; currently not standard outside clinical trials
• Neck dissection: Therapeutic neck dissection for clinically positive nodes (N1-N3); elective neck dissection for clinically negative necks with advanced primary (T3-T4) or if RT dose is inadequate (controversial); timing relative to CCRT varies (concurrent vs. planned neck dissection post-CCRT)

• Surgical options for resectable disease:
• TORS (transoral robotic surgery): Minimally invasive approach with good functional outcomes; expanding role in oropharyngeal cancer
• Open partial or total laryngectomy: For laryngeal cancers; total laryngectomy requires permanent tracheostomy
• Composite resection: For cancers involving bone (mandible, maxilla)

• Metastatic/recurrent disease:
• Platinum-based chemotherapy (cisplatin or carboplatin + 5-FU) for first-line treatment of unresectable/metastatic disease; response rates ~30-40%
• Immunotherapy: Anti-PD-1 inhibitors (pembrolizumab, nivolumab) approved for recurrent/metastatic disease; pembrolizumab monotherapy for PD-L1 positive tumors; response rates

Emergencies

• Airway obstruction: bulky supraglottic/glottic tumor, post-radiation edema, or bilateral vocal cord immobility. Signal is stridor, tripoding, or falling saturations; bag-mask ventilation may fail with a fixed obstruction. For high-grade, fixed glottic/supraglottic obstruction the safer default is awake tracheostomy under local anesthesia, because instrumenting a bulky friable tumor can precipitate complete obstruction or hemorrhage. Awake fiberoptic intubation is reserved for airways that can be safely traversed and where the operator is confident the scope and tube will pass; avoid paralytics and avoid sedation that abolishes spontaneous ventilation until the airway is secured, and have surgical airway equipment and an ENT surgeon immediately at hand.
• Carotid blowout: tumor or post-radiation/post-surgical necrosis erodes the carotid wall. A sentinel bleed from the mouth, tracheostoma, or a wound is the warning sign; management is airway control, volume resuscitation, and emergent endovascular embolization or stenting.
• Aspiration pneumonia: loss of pharyngeal sensation and coordinated swallow after tumor invasion, surgery, or chemoradiation.
• Neutropenic fever during cisplatin-based chemoradiation — empiric broad-spectrum antipseudomonal beta-lactam per IDSA febrile neutropenia guidance.

Disease-related

• Cachexia and malnutrition: obstruction plus odynophagia; NCCN supports proactive nutritional assessment and prophylactic gastrostomy in selected patients.
• Humoral hypercalcemia of malignancy: squamous histology secretes PTHrP — confusion, constipation, short QT, with low PTH and high PTHrP.
• Cranial neuropathies: skull base/perineural spread (nasopharyngeal primaries) causing diplopia (CN VI), facial numbness (CN V), or Horner syndrome.
• Second primary tumors: field cancerization drives an ongoing annual risk in the aerodigestive tract, esophagus, and lung.

Treatment-related

• Cisplatin toxicity: nephrotoxicity (require hydration), high-frequency sensorineural ototoxicity, peripheral neuropathy, magnesium wasting, and severe emesis (highly emetogenic — NCCN/ASCO antiemetic guidelines advise a three- to four-drug regimen including an NK1 antagonist).
• Radiation toxicity: mucositis and dermatitis acutely; chronically xerostomia with rampant dental caries, fibrosis/trismus, esophageal stricture, hypothyroidism (check TSH periodically), accelerated carotid atherosclerosis, and osteoradionecrosis of the mandible — which is why NCCN mandates pre-radiation dental evaluation and extraction.
• Surgical nerve injuries: spinal accessory (CN XI) injury in neck dissection → shoulder droop and trapezius weakness; marginal mandibular branch → asymmetric lower lip; hypoglossal → tongue deviation toward the lesion; thoracic duct injury at left level IV → milky chyle leak.
• Cetuximab: acneiform rash and infusion reactions; PD-1 inhibitors: immune-related thyroiditis, colitis, pneumonitis, hypophysitis.

• A neck mass in an adult over 40 is cancer until proven otherwise: the single best next step for a suspicious, firm, fixed cervical node is fine-needle aspiration (often ultrasound-guided) plus panendoscopy with directed biopsies — never an open excisional lymph node biopsy first, which disrupts fascial planes, seeds the neck, and worsens regional control. This is the most commonly tested distractor on Step 2 CK.

• p16 immunohistochemistry is the surrogate for HPV in oropharyngeal SCC. The stem cues it with a young non-smoker, a tonsillar or base-of-tongue primary, and a cystic neck node that may be misread as a branchial cleft cyst. HPV-positive disease has a distinct, more favorable AJCC 8th-edition staging system and better survival.

• EBV ↔ nasopharyngeal carcinoma. Look for unilateral serous otitis media in an adult (Eustachian tube obstruction by a fossa of Rosenmüller mass), epistaxis, and nasal obstruction — a unilateral middle ear effusion in an adult demands nasopharyngoscopy. Nasopharyngeal carcinoma is treated with radiation/chemoradiation, not primary surgery.

• Persistent dysphonia demands laryngoscopy — know both thresholds. The AAO-HNS Clinical Practice Guideline on Hoarseness (Dysphonia) recommends laryngoscopy, or referral to a clinician who can perform it, when dysphonia has not resolved or improved by 4 weeks, or at any point regardless of duration when a serious underlying cause is suspected — smoker, hemoptysis, neck mass, dysphagia, odynophagia, stridor, unexplained weight loss, or recent neck/thoracic surgery or intubation. Exam vignettes frequently apply a 2-week cut-off in a high-risk (older, smoking, drinking) patient; either way, the wrong answers are empiric antireflux therapy, empiric antibiotics, voice rest, or watchful waiting in a patient with red-flag features.

• Erythroplakia outranks leukoplakia: the velvety red patch carries far higher risk of harboring dysplasia or invasive carcinoma than the white plaque that cannot be scraped off. Both require biopsy.

• Unexplained otalgia with a normal ear exam is referred pain via CN V, IX, or X from a pharyngeal or laryngeal primary — examine the throat, not the ear.

• Extranodal extension and positive margins are the two high-risk pathologic features that mandate adding concurrent cisplatin to postoperative radiation rather than radiation alone (NCCN).

• Distractor to avoid: HPV positivity improves prognosis but does not currently justify treatment de-escalation outside a clinical trial, and tobacco use blunts the survival advantage of HPV-positive disease.