From the Guidelines
Tongue cancer staging should follow the TNM system, which evaluates the primary tumor (T), regional lymph node involvement (N), and distant metastasis (M), with T1 tumors being 2 cm or less in greatest dimension, T2 tumors between 2-4 cm, T3 tumors larger than 4 cm, and T4 tumors invading adjacent structures, as defined by the American Joint Committee on Cancer (AJCC) staging classification 1.
Key Staging Criteria
- T1: tumor 2 cm or less in greatest dimension
- T2: tumor more than 2 cm but not more than 4 cm in greatest dimension
- T3: tumor more than 4 cm in greatest dimension
- T4: tumor invades adjacent structures
Importance of Accurate Staging
Accurate staging is crucial for treatment planning, which may include surgery, radiation therapy, chemotherapy, or a combination depending on the stage, with early-stage cancers typically having better prognoses and requiring less aggressive treatment, while advanced stages often need multimodal therapy 1.
Essential Components of Staging Process
- Clinical examination
- Imaging studies like MRI or CT scans
- Tissue biopsy
Treatment Planning
Treatment planning should be based on the overall stage, ranging from Stage I (early, localized disease) to Stage IV (advanced disease with distant spread), with consideration of lymph node staging ranging from N0 (no regional lymph node metastasis) to N3 (metastasis in a lymph node larger than 6 cm) and distant metastasis (M0 or M1) 1.
Recent Guidelines
Recent guidelines from the National Comprehensive Cancer Network (NCCN) recommend a multidisciplinary treatment approach, with consideration of the patient's nutritional status, dental rehabilitation, and the use of concurrent chemoradiotherapy for advanced resectable tumors 1.
From the Research
Tongue Cancer Staging
- The staging of tongue cancer is crucial for determining the prognosis and appropriate treatment, with the American Joint Committee on Cancer (AJCC) TNM staging system being the most widely used 2.
- The AJCC TNM system classifies cancers based on the size and extent of the primary tumor (T), involvement of regional lymph nodes (N), and the presence of distant metastases (M) 2.
- The 8th edition of the AJCC TNM system, effective for cancer patients diagnosed on or after January 1,2018, introduces new concepts such as depth of invasion (DOI) and extranodal extension (ENE) 2.
Updates to the AJCC TNM Staging System
- The updated 2020 version of the AJCC/UICC TNM staging system has been shown to improve stratification and identification of advanced tumors, reducing the number of T3 classifications and increasing the number of patients with pT4 3.
- The 8th edition of the AJCC TNM staging system has been validated for tongue squamous cell carcinoma, with the addition of DOI to the T classification criteria providing a more accurate prognosis and risk of nodal metastasis 4.
Prognostic Factors
- The immune response, as assessed by tumor-infiltrating lymphocytes (TILs), has been shown to be an important prognostic factor in early oral tongue cancer, with the incorporation of an immune descriptive factor into the staging system improving risk assessment 5.
- The TNM-Immune staging system, which incorporates TILs into the AJCC 8 staging system, has been shown to provide significant discrimination in risk between tumors of T1N0M0-Immune and T2N0M0-Immune, with the latter associated with a worse overall survival 5.
Treatment and Outcomes
- Systemic chemotherapy is indicated for oral squamous cell carcinoma with distant metastasis, and the use of molecular targeted drugs such as cetuximab has improved prognosis 6.
- A case study has shown that a patient with tongue cancer and lung metastases treated with cetuximab combination chemotherapy achieved long-term control of the disease, with no local recurrence or newly emerged metastases observed after nine years 6.