Tongue Cancer

Clinical examination

• Evaluation begins with a thorough visual and manual inspection of the entire oral cavity, tongue, and neck. The tongue is examined for mucosal irregularities, lesions, or areas of induration. Cervical lymph nodes are palpated for enlargement.
  
  

Nasoendoscopy / flexible laryngoscopy

• A thin, flexible endoscope introduced through the nose allows direct visualization of the base of the tongue, oropharynx, and larynx. This is a standard outpatient procedure performed under topical anesthesia and is particularly important for evaluating base-of-tongue lesions not visible on oral examination.

Biopsy

• Tissue biopsy is required for a definitive diagnosis. For accessible oral tongue lesions, incisional biopsy can often be performed under local anesthesia. Lesions at the tongue base may require biopsy under general anesthesia, sometimes combined with fine-needle aspiration of suspicious neck nodes. Histopathological analysis confirms the presence, cell type, grade, and depth of invasion.
  
  

Imaging studies

• Once a diagnosis is confirmed, imaging characterizes the extent of disease:
  • CT (Computed Tomography): Evaluates tumor size, depth, mandibular and bony involvement, and regional lymph node status
  • MRI (Magnetic Resonance Imaging): Provides superior soft tissue detail; particularly valuable for tongue base tumors and assessment of perineural spread
  • PET-CT: Identifies occult regional metastases and distant spread; useful for advanced-stage disease
  • Ultrasound: May be used to guide fine-needle aspiration biopsy of neck lymph nodes

Tongue cancer is staged using the TNM system (Tumor–Node–Metastasis), with the depth of invasion (DOI) incorporated into T-staging for oral tongue tumors:

Stage I

• Tumor ≤ 2 cm; depth of invasion ≤ 5 mm; no lymph node involvement; no distant metastasis

Stage II

• Tumor ≤ 2 cm with DOI > 5 mm; or tumor 2–4 cm with DOI ≤ 10 mm; no nodal involvement

Stage III

• Tumor > 4 cm; or DOI > 10 mm; or single ipsilateral lymph node ≤ 3 cm; no distant metastasis

Stage IVA

• Moderately advanced local or regional disease – adjacent structure invasion or multiple/bilateral lymph nodes

Stage IVB

• Very advanced local disease or lymph node > 6 cm

Stage IVC

• Distant metastasis
  
  

Depth of invasion is a particularly important prognostic variable in oral tongue cancer, as deeper tumors carry a higher risk of occult lymph node metastasis even when the surface dimensions appear limited.

Treatment planning for tongue cancer involves a multidisciplinary team including head and neck surgeons, radiation oncologists, medical oncologists, reconstructive surgeons, and speech-language pathologists.

Surgery

• Surgery is the primary treatment for most oral tongue cancers. The extent of resection depends on tumor size, depth, and proximity to adjacent structures:
  • Transoral excision: For small, accessible oral tongue lesions; often performed under local or general anesthesia
  • Partial glossectomy: Removal of a portion of the tongue for larger or deeper tumors
  • Total glossectomy: Removal of the entire tongue, reserved for advanced cases where partial resection would not achieve adequate oncological margins
  • Neck dissection: Surgical removal of regional lymph nodes from the neck. Elective neck dissection is generally recommended even in clinically node-negative oral tongue cancers with significant depth of invasion, given the high rate of occult nodal metastasis
  • Transoral robotic surgery (TORS): A minimally invasive robotic surgical approach used for selected base-of-tongue tumors, enabling resection through the mouth without external incisions
  • Reconstructive surgery: Significant tissue defects following glossectomy are reconstructed using free tissue to restore tongue form and function

Radiation therapy

• Radiation therapy is used in the following settings:
  • Post-operative adjuvant therapy following surgery when adverse pathological features are present (positive margins, perineural invasion, lymphovascular invasion, multiple lymph nodes)
  • As the primary treatment for base-of-tongue cancers, often in combination with chemotherapy
  • As definitive chemoradiation for advanced tumors where surgery alone is insufficient or not feasible

Chemotherapy

• Chemotherapy is most commonly administered concurrently with radiation therapy as a radiosensitizer, particularly for advanced or base-of-tongue cancers. It is also used for recurrent or metastatic disease.

Immunotherapy

• For recurrent or metastatic tongue cancer not amenable to curative treatment, immune checkpoint inhibitors (including pembrolizumab and nivolumab) have demonstrated clinical activity and are an established treatment option.