Oral Squamous Cell Carcinoma

§ overviewOverview

Malignant epithelial neoplasm; > 90% of all oral malignancies. Sixth most common cancer worldwide.

§ etiologyEtiology

• 01Tobacco (smoked & smokeless)
• 02Alcohol (synergistic with tobacco)
• 03Areca nut
• 04HPV 16 (oropharyngeal)
• 05Chronic trauma
• 06Immunosuppression

§ epidemiologyEpidemiology

M > F, > 50 years. South Asia highest incidence globally.

§ clinicalClinical Features

• 01Non-healing ulcer > 3 weeks
• 02Indurated margins, everted edges
• 03Fixed to underlying tissues
• 04Cervical lymphadenopathy
• 05Common sites: lateral tongue, floor of mouth, gingiva

§ differentialDifferential Diagnosis

• 01Traumatic ulcer
• 02Tuberculous ulcer
• 03Syphilitic gumma
• 04Deep fungal infection

§ histopathHistopathology

• 01Invasive nests and cords of atypical squamous epithelium
• 02Keratin pearls (well-differentiated)
• 03Nuclear pleomorphism, mitotic figures
• 04Broders' grading I–IV

§ investigationsInvestigations

• 01Incisional biopsy — gold standard
• 02CECT / MRI — local extent
• 03USG neck + FNAC — nodal disease
• 04PET-CT — distant metastasis / recurrence
• 05Chest imaging

§ stagingStaging

AJCC 8th ed TNM — DOI (depth of invasion) and ENE (extra-nodal extension) incorporated.

§ treatmentTreatment

• 01Stage I–II: single-modality — surgery OR radiotherapy
• 02Stage III–IV: composite resection + neck dissection + adjuvant CRT
• 03Neck: elective SND for cN0 with DOI > 3 mm
• 04Targeted / immunotherapy: cetuximab, pembrolizumab, nivolumab for recurrent/metastatic

§ complicationsComplications

• 01Loco-regional recurrence
• 02Distant metastasis (lung most common)
• 03Second primary (field cancerisation)

§ prognosisPrognosis

5-year survival: Stage I 80%, Stage IV < 30%.

§ preventionPrevention

• 01Tobacco/alcohol cessation
• 02HPV vaccination
• 03Regular oral screening

§ vivaBDS Viva Questions

• 01Define depth of invasion and its prognostic significance.
• 02Indications for elective neck dissection in cN0 OSCC.

§ pearlsClinical Pearls

• 01Any oral ulcer that fails to heal within 3 weeks must be biopsied.

§ mnemonicsMnemonics

• 01FEAR — Fixed, Everted, Anaesthetic, Rolled edges