Radiation Oncology/Head & Neck/Nasopharynx/Staging

Nasopharynx Cancer Staging

Staging

AJCC 7th edition (2009):
Tumor

T1 - confined to nasopharynx, or tumor extends to oropharynx and/or nasal cavity without parapharyngeal extension
T2 - tumor with parapharyngeal extension (posterolateral infiltration of tumor, i.e. beyond the pharyngobasilar fascia)
T3 - involves bony structures and/or paranasal sinuses
T4 - intracranial extension and/or involvement of cranial nerves, infratemporal fossa, hypopharynx, orbit, or masticator space

Nodes

N1 - unilateral nodes, 6 cm or less, above the supraclavicular fossa, and/or retropharyngeal lymph nodes 6 cm or less (unilateral or bilateral)
N2 - bilateral nodes, 6 cm or less, above the supraclav fossa
N3a - lymph node greater than 6 cm
N3b - extension to the supraclav fossa (defined as the triangular region described by Ho, bounded by the superior margin of the sternal head of the clavicle, the superior margin of the lateral end of the clavicle, and the point where the neck meets the shoulder. This includes some of level IV as well as V.)

Overall stage

Changes from 6th edition

Notes

Shift of more advanced N-stages into lower stage groupings — N1 is stage II instead of III, N2 is III instead of IV
Retropharyngeal nodes staging has been controversial, since CT is often unable to differentiate them from parapharyngeal involvement of primary tumor. However, MRI appears more sensitive, and patients who are N0 but with positive RLN by MRI have prognosis similar to patients with N1 disase as should probably be classified as such

Tumor

T1 - confined to nasopharynx
T2 - extends to soft tissues
- T2a - extends to oropharynx and/or nasal cavity without parapharyngeal extension
- T2b - any tumor with parapharyngeal extension (i.e. beyond the pharyngobasilar fascia)
T3 - involves bony structures and/or paranasal sinuses
T4 - intracranial extension and/or involvement of cranial nerves, infratemporal fossa, hypopharynx, orbit, or masticator space

Nodes

N1 - unilateral nodes, 6 cm or less, above the supraclavicular fossa
N2 - bilateral nodes, 6 cm or less, above the supraclav fossa
N3a - lymph node greater than 6 cm
N3b - extension to the supraclav fossa (defined as the triangular region described by Ho, bounded by the superior margin of the sternal head of the clavicle, the superior margin of the lateral end of the clavicle, and the point where the neck meets the shoulder. This includes some of level IV as well as V.)

Overall stage

Notes

Division of Stage II into A and B compared to other H&N sites
Shift of more advanced N-stages into lower stage groupings — N1 is stage II instead of III, N2 is III instead of IV
Retropharyngeal nodes staging has been controversial, since CT is often unable to differentiate them from parapharyngeal involvement of primary tumor. However, MRI appears more sensitive, and patients who are N0 but with positive RLN by MRI have prognosis similar to patients with N1 disase as should probably be classified as such

Overall stage:

(similar to other H&N sites in newest staging system)

Note: downstaging of disease in AJCC 4th edition — N1 was moved to Stage II and N2 was moved to Stage III. This is an important difference to note when comparing older trials to newer treatment modalities since the definition of "advanced stage" has changed.

T1 - nasopharynx only
T2 - nasal cavity, oropharynx, soft palate, anterior cervical vertebrae soft tissue, proximal parapharyngeal space
T3 - distal parapharyngeal space, CN involvement, base of skull, pterygoprocss zone, pterygopalatine fossa
T4 - multiple CN involvement, paranasal sinus, cavernous sinus, orbit, infratemporal fossa, or C1-C2 vertebra

Staging:

T1 - nasopharynx only
T2 - extension to nasal fossa, oropharynx, or parapharyngeal region
T3 - bony involvement, skull base, cranial nerve palsy, orbits, laryngopharynx, or infratemporal fossa