Shared Nodal Categorization & Group Staging

• Many disease sites within the head and neck share the same nodal categorization system and the same group staging system (described below).
• Disease sites that share the same common nodal staging:
  1. Oral Cavity
  2. Oropharynx (p16-)
  3. Hypopharynx
  4. Larynx
  5. Nasal Cavity & Paranasal Sinuses
  6. Major Salivary Glands
  7. Cutaneous Carcinoma of the Head & Neck
• Notably this includes everything in the upper aerodigestive tract except for nasopharyngeal carcinoma and p16+ oropharyngeal carcinoma.
  • Other exceptions include melanoma, thyroid carcinoma, and head and neck sarcoma.
• The majority of the above disease sites also use the same group staging system.
  • The only exception is cutaneous carcinoma of the head and neck which is essentially the same except that it does not divide Stage IV into IVA/IVB/IVC.

• Extranodal extension is now recognized as a major prognosticator in nodal categorization.
• The nodal categorization system is now slightly different between clinical and histopathological evaluation.
• p16+ oropharyngeal carcinoma was previously staged using this shared system but now has its own unique staging system.

Clinical Nodal Categorization
(Shared Categorization System)

Pathologic Nodal Categorization
(Shared Categorization System)

General Rules

• If a patient has any clinical extranodal extension, they are automatically be categorized in the maximum possible N sub-category (N3b).
• Pathologic N categorization is almost the same except for the isolated situation of having a single ipsilateral lymph node that is 3 cm or less with ENE identified only on pathology.
  • Instead of being up-categorized to N3b, this specific case is up-categorized to N2a instead.
  • In all other situations where there is ENE (clinical or pathologic), they are still up-categorized to N3b.
• Clinically the AJCC defines ENE as invasion of skin, infiltration of musculature/fixation to adjacent structures on clinical examination, cranial nerve, brachial plexus, sympathetic trunk or phrenic nerve invasion with dysfunction.

Extranodal Extension (ENE)

• Pathologically, ENE is defined as extension of metastatic tumour beyond the confines of the lymph node itself.
• Clinically the AJCC defines ENE as invasion of skin, infiltration of musculature/fixation to adjacent structures on clinical examination, cranial nerve, brachial plexus, sympathetic trunk or phrenic nerve invasion with dysfunction.
• ENE found on pathologic examination is designated as either ENE_mi (microscopic ENE ≤ 2 mm), or ENE_ma (major ENE > 2 mm. Both are still considered ENE+ for the definition of pN (this is only important for data collection and future analysis currently).

Shared Group Staging System

General Rules

• Straightforward to remember due to the pattern seen above when creating a table against the T and N staging.
• (T1 N0) is staged as Stage I, and (T2, N0) is staged as Stage II. Thereafter, each increasing stage is immediately to the right and below the previous stage.