Head and Neck Cancer - Squamous Cell Carcinoma

Head and Neck Cancer - Squamous Cell Carcinoma

 

Squamous cell carcinoma (SCC) of the head and neck is the most common malignancy of the upper aerodigestive tract.

Epidemiology

  • Prevalence – 34,000 new cases per year in the U.S.
  • Age – 50-60 years
  • Sex – males: females; 3:1
  • Ethnicity – African Americans more at risk than Caucasians

Risk Factors

  • Tobacco use – 5-25 fold higher risk
  • Alcohol use – if combined with smoking, geometrically increases risk
  • Occupational exposures
    • Exposure to nickel refining, chromium, mustard gas, radium
    • Woodworking and tanning byproducts
  • Viral infection
    • Epstein-Barr – associated with nasopharyngeal carcinoma
    • HPV 16/18/31 – most highly associated with carcinoma of lingual and palatine tonsils
  • Betel nut chewing

Pathology

  • The aerodigestive tract is lined with squamous cells
  • The majority of cancers arising in the aerodigestive tract are of squamous cell origin (90%)
  • Increased incidence over the past 10 years of the disease due to increased cancer of the base of the tongue and tonsils
  • Premalignant diseases (leukoplakia, erythroplakia, and dysplasia) can precede frank malignancy
  • SCC antigen
    • SCC antigen is expressed in normal epithelium and epithelial tissues
    • Neutral forms of SCC antigen normally remain inside the cell
    • Acidic SCC antigen is released and is often elevated in patients having SCC or other nonmalignant squamous cell lesions
  • Lipid associated sialic acid
    • Elevated concentrations of sialic acid are noted in inflammatory disorders and significant tissue necrosis
    • In cancer patients, elevated concentrations of sialic acid can be from the tumor cell surfaces as well as the nonspecific inflammatory responses associated with the malignancy
    • Malignant cells often exhibit aberrant sialylation, which has been implicated in the loss of contact inhibition and the metastatic potential of these cells

Clinical Presentation

  • Oral cavity – nonhealing ulcers of the floor of the mouth, tongue, buccal mucosa, hard palate; pain
  • Hypopharynx – hoarseness, dysphagia, otalgia, enlarged cervical nodes
  • Pharynx – tonsils, sore throat, otalgia, odynophagia
  • Nasopharyngeal – usually late symptoms of bleeding, obstruction, cranial nerve palsy; otitis media unresponsive to antibiotics  
  • Salivary glands – swelling, adenopathy

Diagnosis

  • Laboratory testing
    • Tissue histology is gold standard for diagnosis
  • Imaging studies
    • CT/MRI/PET

Disease monitoring

  • SCC Antigen
    • Monitoring test only (not intended for use in diagnosing cancer)
    • Serial determinations (pre and post surgery) are most useful in following cancer recurrence
    • Antigen levels decrease to normal levels approximately 96 hours after removal of lesion
  • Lipid associated sialic acid
    • Limited use as a marker in SCC
  • Potential prognostic markers
    • p53 (nuclear phosphoprotein)
    • EGFR (epidermal growth factor receptor)

See Also