Unknown/Occult Primary Cancers (CUP) of Head & Neck: Diagnostic approach

Determine pathology of lymph node: Fine needle aspiration cytology (FNAC) / core needle biopsy / surgical biopsy
Try to identify primary tumour
- Symptoms related to upper aerodigestive tract, prior skin cancers
- Examine nose, nasopharynx, oral cavity, oropharynx, hypopharynx, larynx, skin, thyroid
- Palpate tonsils, base of tongue and retract tonsillar pillars, and then re-examine for bleeding
- Cystic nodes: suspect oropharynx / skin cancer
- Nodal location and laterality suggest location of primary
  - Levels 1a,b: Oral cavity, nose, sinuses
  - Levels 2, 3: Oral cavity, oropharynx, hypopharynx, larynx, nose, sinuses
  - Level 4: Larynx, hypopharynx, thyroid, oral tongue, floor of mouth
  - Level 5: Nasopharynx, posterior scalp, thyroid
  - Level 6: Thyroid, subglottis, hypopharynx, oesophagus
  - Nodes along external jugular vein: Facial skin
  - Bilateral: Midline, base of tongue, soft palate, supraglottis, hypopharynx, nasopharynx (NPC)
- Immunohistochemistry: EBV (NPC); P16 (oropharynx, skin, nasopharynx, oral cavity); melanoma; thyroid; salivary; lymphoma etc.
- CT or MRI or PET (Law of diminishing returns and additional costs with >1 imaging modality)
- Panendoscopy, guided biopsies, tonsillectomy
Exclude distant metastases: CXR / CT / PET
Stage the cancer
Select appropriate treatment, preferably as a multidisciplinary team
- Cure vs palliation
- General fitness to undergo surgery +/ (chemo)radiation
- Ability to deal with consequences of treatment