What is the primary treatment for oral squamous cell carcinoma?

Primary Treatment for Oral Squamous Cell Carcinoma

The primary treatment for oral squamous cell carcinoma is surgery followed by adjuvant radiotherapy or chemoradiotherapy in cases with adverse pathological features, with primary surgical treatment being the preferred approach for T3/T4 oral cavity cancers. 1

Treatment Approach Based on Disease Stage

Early Stage Disease (T1-2, N0)

• Early disease should be treated with a single-modality approach whenever possible 1
• Options include:
  • Conservative surgery (including transoral laser microsurgery or transoral robotic surgery) 1
  • Radiotherapy (external beam or brachytherapy for selected stage I cases) 1
• The choice between surgery and radiotherapy should be based on expected functional outcomes and treatment-related morbidity 1

Locally Advanced Disease (T3-4, N0-3)

• Standard options include:
  • Primary surgical treatment followed by adjuvant RT or CRT (preferred for T3/T4 oral cavity cancers) 1
  • Primary concomitant chemoradiotherapy for non-resectable cases 1
• For oral cavity cancers, wide surgical excision with appropriate reconstruction is recommended 1
• Almost all surgically treated tumors will require postoperative RT or CRT depending on pathological findings 1

Indications for Adjuvant Therapy

Postoperative Radiotherapy

• Recommended for patients with: 1
  • pT3-4 tumors
  • Resection margins with macroscopic (R2) or microscopic (R1) residual disease
  • Perineural infiltration
  • Lymphatic infiltration
  • More than one invaded lymph node
  • Presence of extracapsular infiltration
  • Depth of invasion >10 mm 2

Postoperative Chemoradiotherapy

• Recommended for patients with: 1
  • R1 resection (positive margins)
  • Extracapsular extension
• Should start within 6-7 weeks after surgery 1

Radiotherapy Considerations

• All patients should be treated with intensity-modulated radiotherapy (IMRT) or volumetric modulated arc therapy (VMAT) 1
• For concurrent chemoradiotherapy, the standard chemotherapy regimen is cisplatin at 100 mg/m² on days 1,22, and 43 of radiotherapy (70 Gy) 1
• For patients unfit for cisplatin, alternatives include: 1
  • Carboplatin combined with 5-FU
  • Cetuximab with radiotherapy
  • Hyperfractionated or accelerated radiotherapy without chemotherapy

Management of Recurrent/Metastatic Disease

• For patients with PD-L1 expressing tumors: 1
  • Pembrolizumab in combination with platinum/5-FU
  • Pembrolizumab monotherapy
• For patients with non-PD-L1 expressing tumors: 1
  • Platinum/5-FU/cetuximab remains standard therapy
• For patients who progress within 6 months of platinum therapy: 1
  • Nivolumab or pembrolizumab

Important Considerations and Caveats

• Treatment should be discussed in a multidisciplinary team including supportive specialties 1
• Patients should be treated at high-volume facilities for better outcomes 1
• Postoperative radiotherapy outcomes are more promising than definitive radiotherapy for inoperable disease 3
• Depth of invasion >10 mm is associated with higher risk of recurrence 2
• DPD testing is recommended before initiating 5-FU treatment 1
• Neck dissection is not recommended in cases of negative FDG-PET and normal size lymph nodes at 12 weeks post-CRT 1

Follow-up

• Close monitoring is essential to detect early locoregional recurrence or new primaries 1
• Follow-up should include the entire head and neck multidisciplinary team 1
• The risk of disease relapse is 40-60% for locally advanced disease, with most recurrences occurring within the first 2 years 1