Tongue Cancer Staging and Treatment Using the TNM System
The TNM staging system for tongue cancer is essential for determining prognosis and guiding treatment, with stage I-II disease representing smaller primary tumors without nodal involvement, and stage III-IV representing larger tumors that may invade underlying structures and/or spread to regional nodes.1
TNM Classification for Tongue Cancer
T (Primary Tumor) Classification
- T1: Tumor ≤2 cm in greatest dimension with depth of invasion (DOI) ≤5 mm 2, 3
- T2: Tumor ≤2 cm with DOI >5 mm and ≤10 mm, or tumor >2 cm but ≤4 cm with DOI ≤10 mm 3, 4
- T3: Tumor >4 cm or any tumor with DOI >10 mm 3, 4
- T4a (moderately advanced): Tumor invades adjacent structures (e.g., through cortical bone, deep/extrinsic muscle of tongue) 1
- T4b (very advanced): Tumor invades masticator space, pterygoid plates, skull base, or encases carotid artery 1
N (Regional Lymph Node) Classification
- N0: No regional lymph node metastasis 1
- N1: Metastasis in a single ipsilateral lymph node, ≤3 cm in greatest dimension 1
- N2: Metastasis as specified in N2a, N2b, or N2c 1
- N3: Metastasis in a lymph node >6 cm in greatest dimension 1
M (Distant Metastasis) Classification
Stage Grouping
- Stage I: T1N0M0 1
- Stage II: T2N0M0 1
- Stage III: T3N0M0 or T1-3N1M0 1
- Stage IVA: T4aN0-1M0 or T1-4aN2M0 (moderately advanced local/regional disease) 1
- Stage IVB: T4b, any N, M0 or any T, N3, M0 (very advanced local/regional disease) 1
- Stage IVC: Any T, any N, M1 (distant metastatic disease) 1
Important Staging Considerations
- Depth of invasion (DOI) is a critical factor in determining T stage and has been officially incorporated in the 8th edition of TNM classification 2, 4
- DOI >4 mm is associated with higher risk of nodal metastases and may warrant elective neck dissection 2
- High-frequency intraoral ultrasound (IOUS) can accurately assess DOI preoperatively with sensitivity of 92.31% and specificity of 82.14% for predicting DOI ≥4 mm 2
- The 8th edition TNM staging system shows improved hazard discrimination compared to the 7th edition 3, 4
Treatment Approach Based on Stage
Early Stage Disease (Stage I-II)
- Single-modality treatment with either surgery or radiation therapy 1
- For T1N0M0 and T2N0M0: Surgery with or without post-operative radiotherapy 1
- For glottic carcinomas: Radiotherapy may be used instead of surgery with curative intent 1
- Consider elective neck dissection for tumors with DOI >4 mm due to high risk of occult nodal metastases 2
Advanced Stage Disease (Stage III-IVA)
- Combined modality therapy is generally recommended 1
- Standard options include surgery with post-operative radiotherapy or chemoradiotherapy 1
- Postoperative chemoradiation with cisplatin alone is category 1 recommendation for high-risk features 1
- Induction chemotherapy options include docetaxel/cisplatin/5-FU (category 1 if induction is chosen) 1
Very Advanced Disease (Stage IVB)
- Chemoradiotherapy (concomitant or alternated) is recommended (category 1) 1
- Platinum-based regimens remain the standard chemotherapy for concurrent chemoradiotherapy 1
- For patients with poor performance status, standard radiotherapy alone should be considered 1
Metastatic Disease (Stage IVC)
- Palliative chemotherapy is the standard option 1
- Combination therapy options include:
Treatment Considerations
- A multidisciplinary treatment approach should be established in all cases 1
- Dental evaluation and rehabilitation is indicated prior to radiotherapy 1
- Nutritional status must be corrected and maintained throughout treatment 1
- For organ preservation in advanced cases, cisplatin with 5-fluorouracil is the chemotherapy of choice 1
- Continuous intra-arterial CBDCA infusion chemotherapy in combination with radiation therapy has shown promising results for locally advanced tongue cancer with 5-year local control rate of 65% 5