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

• I - T1 N0
• II - T1-T2 N1, T2 N0 (i.e. T2 or N1)
• III - T3 N0-2, or T1-3 N2 (i.e. T3 or N2)
• IVA - T4 N0-2
• IVB - N3
• IVC - M1

Changes from 6th edition

• T2a lesions moved to T1. T2b moved to T2.
• Stage IIB was moved to II and Stage IIA merged with Stage I
• New designation for retropharyngeal lymph nodes (all are N1 nodes)

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

Older staging systems

AJCC 6th edition (2002)

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

• I - T1 N0
• IIA - T2a N0
• IIB - T1-T2 N1, T2b N0 (i.e. T2b or N1)
• III - T3 N0-2, or T1-3 N2 (i.e. T3 or N2)
• IVA - T4 N0-2
• IVB - N3
• IVC - M1

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

AJCC 5th edition (1997)

• same as 6th edition

AJCC 4th edition (1988):

• T1 - tumor confined to one wall of the nasopharynx
• T2 - two walls or more
• T3 - extension to oropharynx and nasal cavity
• T4 - invades skull base or cranial nerve

• N1 - single ipsilateral node <= 3 cm
• N2a - single ipsilateral node 3-6 cm
• N2b - multiple ipsilateral nodes < 6 cm
• N2c - contralateral or bilateral nodes < 6 cm
• N3 - nodes > 6 cm

Overall stage:

• I - T1 N0
• II - T2 N0
• III - T3 or N1
• IV - T4 or N2-3 or M1

(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.

Chinese Staging (1992)

• 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

• N0 - no nodes
• N1 - upper cervical LN <4cm
• N2 - lower cervical LN, or 4-7 cm
• N3 - SCV, or >7cm, or fixed, or skin infiltration

Staging:

• I - T1N0
• II - T2 or N1
• III - T3 or N2
• IVA - T4 or N3
• IVB - M1

Ho's Staging (1978)

• 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

• N0 - no nodes
• N1 - above laryngeal cartilage
• N2 - below laryngeal cartilage but above SCV fossa
• N3 - SCV lymph nodes