1. Introduction
Head and neck cancers (HNCs) are a heterogeneous group of malignancies arising from the upper aerodigestive tract, including the oral cavity, pharynx, larynx, nasal cavity, paranasal sinuses, salivary glands, and thyroid. The majority are squamous cell carcinomas (HNSCC) originating from mucosal epithelium. These cancers are common in South Asia due to high exposure to tobacco, alcohol, and betel nut.
2. Types of Head and Neck Cancer
A. Based on Anatomical Site
- Oral cavity cancer (tongue, buccal mucosa, floor of mouth)
- Oropharyngeal cancer (tonsil, base of tongue)
- Nasopharyngeal carcinoma
- Hypopharyngeal cancer
- Laryngeal cancer
- Nasal cavity & paranasal sinus cancers
- Salivary gland tumors
- Thyroid cancer (sometimes included)
B. Based on Histology
- Squamous cell carcinoma (≈90%)
- Adenocarcinoma
- Mucoepidermoid carcinoma
- Adenoid cystic carcinoma
- Lymphoma
- Sarcoma
3. Pathogenesis
- Chronic exposure to carcinogens causes genetic and epigenetic alterations
- Progressive dysplasia → carcinoma in situ → invasive cancer
Key Molecular Events
- TP53 mutation
- EGFR overexpression
- Cyclin D1 amplification
- Loss of tumor suppressor genes
Important Risk Factors
- Tobacco smoking and chewing
- Alcohol consumption
- Betel nut (areca nut) use
- HPV infection (HPV-16) – oropharyngeal cancer
- EBV infection – nasopharyngeal carcinoma
- Poor oral hygiene
- Occupational exposure (wood dust, nickel)
- Radiation exposure
4. Clinical Features
- Non-healing oral ulcer
- Persistent sore throat
- Dysphagia
- Hoarseness of voice
- Neck lump (lymphadenopathy)
- Unexplained weight loss
- Ear pain (referred otalgia)
5. Laboratory Diagnosis
A. Clinical Examination
- Visual inspection and palpation
- Endoscopy (nasopharyngoscopy, laryngoscopy)
B. Cytology & Histopathology
- FNAC of neck lymph nodes
- Biopsy of primary lesion (gold standard)
- Histopathology grading and staging
C. Molecular & Ancillary Tests
- HPV testing (p16 IHC, PCR)
- EBV serology / PCR
- Immunohistochemistry (p63, CK5/6, EGFR)
D. Imaging
- Contrast-enhanced CT scan
- MRI (soft tissue involvement)
- PET-CT (staging & recurrence)
6. Treatment
A. Surgery
- Early-stage tumors
- Wide local excision
- Neck dissection (nodal disease)
B. Radiotherapy
- Primary or adjuvant treatment
- Intensity-modulated radiotherapy (IMRT)
C. Chemotherapy
- Cisplatin-based regimens
- Concurrent chemoradiation
D. Targeted Therapy
- Cetuximab (EGFR inhibitor)
E. Immunotherapy
- Pembrolizumab
- Nivolumab
- Used in recurrent/metastatic disease
7. Prevention
- Tobacco and alcohol cessation
- Betel nut avoidance
- HPV vaccination
- Oral hygiene and dental care
- Early screening of high-risk individuals
- Occupational safety measures
- Public awareness programs
8. Prognosis
- Strongly dependent on stage at diagnosis
- HPV-positive oropharyngeal cancers have better outcomes
- Advanced disease has high recurrence rates
9. Keynotes
- Squamous cell carcinoma is the predominant histology
- Tobacco and alcohol are major risk factors
- HPV-16 is linked to oropharyngeal cancer
- Biopsy is the diagnostic gold standard
- Multimodal therapy improves survival
- Early detection significantly improves prognosis
Further Readings
- https://onlinelibrary.wiley.com/doi/10.1002/mco2.702
- https://pubmed.ncbi.nlm.nih.gov/34562395
- https://www.hopkinsmedicine.org/health/conditions-and-diseases/head-and-neck-cancer#
- https://pmc.ncbi.nlm.nih.gov/articles/PMC3589176
- https://www.researchgate.net/publication/395824372_HEAD_AND_NECK_SQUAMOUS_CELL_CARCINOMA_A_COMPREHENSIVE_REVIEW_OF_ETIOLOGY_PATHOGENESIS_DIAGNOSIS_TREATMENT_AND_FUTURE_DIRECTIONS
- https://www.apollohospitals.com/proton-therapy/blogs/head-and-neck-cancer-diagnosis
- https://www.cancerresearchuk.org/about-cancer/head-neck-cancer
- https://www.aijoc.com/doi/10.5005/jp-journals-10003-1013
- https://www.mdpi.com/2075-4418/14/21/2365
- https://www.ncbi.nlm.nih.gov/books/NBK65816
- https://together.stjude.org/en-us/conditions/cancers/diagnosing-childhood-cancer.html
