Treatment of Mouth Cancer
The standard treatment for mouth cancer (oral cavity cancer) is primarily surgical resection for resectable tumors, with radiotherapy or chemoradiotherapy reserved for adjuvant treatment or for patients who are medically inoperable or refuse surgery. 1
Diagnosis and Staging
- Complete physical examination including neck palpation and flexible head and neck fibreoptic endoscopy
- Pathological confirmation through biopsy is mandatory
- Imaging studies:
- Contrast-enhanced CT scan and/or MRI to assess primary tumor and regional lymph nodes
- Chest imaging (at minimum chest CT) to assess for distant metastases
- FDG-PET/CT recommended for high-risk tumors or suspected recurrence
- p16 immunohistochemistry for oropharyngeal tumors to determine HPV status
Treatment Algorithm Based on Stage
Early Stage Disease (T1-2, N0)
Primary treatment options:
- Conservative surgery (preferred for oral cavity) 1
- Radiotherapy (for selected patients who are medically inoperable or refuse surgery)
Surgical approaches:
- Transoral approaches (including laser microsurgery or robotic surgery) for appropriate cases
- Selective neck dissection guided by tumor thickness (even for clinically N0 disease)
- For tumors with depth of invasion <5mm and cT1N0, active surveillance of the neck is an option
- For tumors with depth of invasion <10mm, sentinel lymph node biopsy is a valid option
Radiotherapy as primary treatment:
- External beam RT or brachytherapy for selected stage I cases
- Dose of 44-64 Gy to the neck for T1-2, N0 disease 1
Locally Advanced Disease (T3-4a, N0-3)
Resectable disease:
- Surgery followed by risk-adapted adjuvant therapy 1
- Adjuvant radiotherapy (58-63 Gy) for high-risk features:
- pT3-4 tumors
- Close margins (1-5mm)
- Perineural infiltration
- Lymphovascular spread
- Multiple positive lymph nodes
- Adjuvant chemoradiotherapy (66 Gy with cisplatin) for:
- Positive margins (R1 resection)
- Extracapsular nodal spread
- Postoperative treatment should start within 6-7 weeks after surgery 1
Unresectable disease (T4b and/or unresectable lymph nodes):
- Concomitant chemoradiotherapy
- Induction chemotherapy followed by RT or chemoradiotherapy for responders
- Palliative treatment for poor performance status patients
Recurrent and/or Metastatic Disease
For recurrent disease:
- Evaluate for salvage surgery or re-irradiation in selected cases
For metastatic disease:
- PD-L1 positive tumors:
- Pembrolizumab monotherapy (for CPS ≥1) or
- Pembrolizumab plus platinum/5-FU
- PD-L1 negative tumors:
- Platinum/5-FU/cetuximab (EXTREME regimen)
- After progression on platinum-based therapy:
- Nivolumab or pembrolizumab (for immunotherapy-naïve patients)
- PD-L1 positive tumors:
Important Considerations
- Multidisciplinary team involvement is crucial for oral cavity cancers due to critical physiologic functions of mastication, deglutition, and speech articulation 1
- Nutritional assessment is essential; significant malnutrition (>10% weight loss in 6 months) requires nutritional support before treatment 1
- Dental evaluation and rehabilitation before radiotherapy is necessary to prevent complications
- Thyroid function should be monitored after neck irradiation (TSH every 6-12 months) 1
Follow-up Recommendations
- Regular clinical examinations to monitor for recurrence and second primaries
- Most recurrences occur within the first 2 years after treatment
- Imaging studies as clinically indicated
- Assessment of treatment-related complications and functional outcomes
The treatment of oral cavity cancer requires a careful balance between oncologic control and preservation of function. While organ preservation approaches using chemotherapy have been extensively studied for other head and neck sites, they have received less attention for oral cavity cancers because functional outcomes after primary surgical management are often good with modern reconstruction techniques 1.