Head and Neck Cancer Evaluation and Staging
What staging questions test
You must know the AJCC principles: clinical (cTNM) versus pathologic (pTNM) staging, the meaning of the prefix (c, p, y for post-treatment, r for recurrence), and that staging is site-specific. For head and neck, the mucosal primary, nodal disease, and extranodal extension (ENE) drive stage. ENE is now a major nodal descriptor-its presence upstages substantially and changes adjuvant therapy. Know that HPV-positive oropharyngeal cancer has its own staging system separate from HPV-negative disease.
Evaluation workup
Understand the role of history and physical with flexible endoscopy, imaging (contrast CT or MRI for primary and neck; PET-CT for advanced disease, unknown primary, or suspected distant disease), and tissue diagnosis. Sentinel node biopsy has a defined role in early oral cavity with clinically negative neck in some settings. Know when to suspect an unknown primary (cystic neck node, HPV/p16 testing) and the workup sequence.
Traps
Classic traps: calling a node "fixed" without justification; misassigning T category for a primary that invades a specific structure (e.g., bone invasion vs superficial erosion); forgetting that ENE requires pathologic confirmation for pN but imaging suspicion influences planning; and applying the general staging system to HPV-positive oropharynx. Another trap is confusing clinical versus pathologic nodal size thresholds.
Rule of thumb
Stage what you can prove. Use imaging and exam for cTNM, reserve pTNM for resection specimens, and always ask whether ENE is present because it is the single most consequential nodal finding. Example: a 3 cm HPV-positive oropharyngeal node without ENE is staged under the HPV system, not the general system-applying the wrong system is a frequent distractor.