Staging in Head and Neck Cancer
Head and neck cancer staging must follow the TNM system based on the AJCC 8th edition, with initial evaluation including physical examination, endoscopy, and contrast-enhanced CT or MRI of the primary site and neck, plus thoracic CT to exclude distant metastases. 1
TNM Staging Framework
The TNM system provides the anatomic foundation for prognosis and treatment planning in head and neck cancer 1:
- T (Tumor) staging assesses primary tumor size and extent of invasion into surrounding structures 1
- N (Node) staging evaluates cervical adenopathy including laterality, size, nodal level (for nasopharynx), and presence of extranodal extension 1
- M (Metastasis) staging determines presence of distant disease, pursued based on clinical suspicion in advanced locoregional disease 1
Critical T4 Subdivision
T4 tumors are subdivided into T4a (moderately advanced/resectable) and T4b (very advanced/unresectable), which fundamentally alters treatment approach and prognosis 1, 2. Stage IV disease is correspondingly subdivided into IVa, IVb, and IVc (metastatic disease) 1.
Required Staging Workup
Mandatory Components
- Physical examination with careful palpation of primary site and neck 1, 2
- Head and neck endoscopy for direct visualization and biopsy 1, 2
- Imaging of primary and neck: CT with contrast OR MRI with contrast (MRI preferred for all subsites EXCEPT larynx and hypopharynx where CT is acceptable) 2
- Thoracic CT scan to rule out lung metastases and synchronous lung primaries 1, 2
- WHO-classified surgical biopsy for definitive histologic diagnosis 2
Role of PET/CT
PET/CT has lower specificity than sensitivity and is more useful for detecting distant metastases or synchronous tumors than for neck node staging 2. PET/CT imaging should extend from skull base to vertex to ensure complete tumor inclusion 1. While some data suggest PET/CT may improve overall TNM staging accuracy, particularly for T-staging in patients with metallic implants 3, its role at initial staging remains investigational per established guidelines 1.
Treatment Algorithm by Stage
Early Stage (I-II)
Either conservative surgery OR radiotherapy (external beam or brachytherapy) provides equivalent locoregional control, though this recommendation is based on retrospective data without randomized trial support 1, 2. Modern radiotherapy must utilize 3D conformal radiation therapy or intensity-modulated radiation therapy (IMRT) 1.
Locally Advanced (III-IV)
The treatment approach depends on resectability and anticipated functional outcome:
For resectable disease with acceptable functional outcome:
- Surgery with reconstruction followed by postoperative radiotherapy 1, 2
- Mandatory addition of postoperative chemoradiotherapy with single-agent platinum for high-risk pathologic features (extracapsular nodal extension and/or R1 resection) 1, 2
For resectable disease with poor anticipated functional outcome:
- Concurrent chemoradiotherapy is preferable to preserve organ function 1
For unresectable disease (T4b):
- Concurrent chemoradiotherapy is the standard treatment 1
Special Considerations
Cancer of Unknown Primary
When metastatic cervical lymphadenopathy is identified without evident primary (1-4% of head and neck malignancies), every attempt must be made to identify the primary site as this impacts prognosis and treatment 1. When pathology shows HPV-related squamous cell carcinoma, the primary is presumed to localize to the oropharynx 1. Despite multimodality imaging and endoscopy, 2-9% of primary sites remain undetected 1.
Essential Supportive Measures
A multidisciplinary treatment plan is mandatory in all cases 1, 2. Critical supportive interventions include:
- Nutritional status correction and maintenance throughout treatment 1, 2
- Dental rehabilitation completed BEFORE initiating radiotherapy 1, 2
Common Pitfalls
The presence of nodal metastases typically results in disease upstaging and alters treatment planning, including extent of neck dissection or radiation field 1. Failure to adequately assess nodal disease can lead to undertreatment. Additionally, the TNM system is based primarily on anatomic information and does not capture tumor biology, patient symptoms, or comorbidities that independently predict survival 4, 5, so clinical judgment beyond staging is essential for optimal management.