Temporal bone cancer staging systems

Temporal bone

This article is mainly intedend for use by medical professionals.

Staging of cancers is essential for patient counseling, treatment planning, predict treatment outcome and survival. Most commonly followed staging system for head and neck malignancies is the Tumor, Node, Metastasis (TNM staging system) by the American Joint Committee on Cancer (AJCC).

Because of the relative rarity of temporal bone cancers, a universally accepted temporal bone cancer staging system is not available. So far, no system has been adopted by the American Joint Committee on Cancer or the International Union for Cancer Control.

Several institutional case series have been published, each with their own somewhat similar 2–4 level staging system. But none of these have been validated or in widespread use.

Following are some of the most commonly available temporal bone cancer staging systems.

Goodwin and Jesse staging system (1980)

Group 1 Tumors that involve the pinna and/or cartilaginous canal.
Group 2 Tumors within the bony ear canal or mastoid cortex
Group 3 Tumors involving the deep structures of the temporal bone (middle ear, facial canal, skull base, or mastoid air cells)

Patients in groups 1 and 2 had similar 5-year overall survival rates, at 57% and 45%, respectively. Those in group 3 saw a lower survival rate of 29%. While the majority of tumors were squamous cell carcinoma, nearly 24% of the tumors in group 3 were of salivary gland origin.

Stell and McCormack staging system (1985)

T1 Tumor limited to the site of origin, that is, with no facial nerve paralysis and no bone destruction.
T2 Tumor extending beyond the site of origin indicated by facial paralysis or radiological evidence of bone destruction, but no extension beyond the organ of origin
T3 Clinical or radiological evidence of extension to surrounding structures (dura, the base of the skull, parotid gland, temporomandibular joint, etc.)
Tx Patients with insufficient data for classification, including patients previously seen and treated elsewhere.

A modification was suggested for Stell and McCormack classification by Clark et al. (1991), suggesting redefinition of T3 to include tumors with parotid, TMJ, and skin involvement, i.e., extracranial disease, and to make a T4 category for tumors with involvement of dura/base of skull, i.e., intracranial disease.

Pensak et al. / University of Cincinnati grading system (1996)

Grade I Tumor in a single site, <1 cm.
Grade II Tumor in a single site, but >1 cm.
Grade III Transannular tumor extension (i.e., ear canal and middle ear involvement)
Grade IV Mastoid or petrous air-cell invasion
Grade V Periauricular or contiguous extension (extratemporal)
Grade VI Neck adenopathy, distant site, or infratemporal fossa

A shortcoming of this temporal bone cancer staging systems was the use of “grade” to describe stage. This potentially confuses with histologic grading. Additionally, the lumping of distant disease with a disease in the infratemporal fossa or neck would be obviated by using a TNM formulation.

Manolidis staging system (1998)

Stage 1 Disease confined to external auditory canal including spread from auricular cancer to the canal and confined to it
Stage 2 The disease spread from external auditory canal to one or more of the following:

  1. Temporomandibular joint
  2. Parotid
  3. Infratemporal fossa
Stage 3 The spread of disease from external auditory canal to one or more of the following:

  1. Middle ear
  2. Mastoid
  3. Facial nerve and Fallopian canal
Stage 4 The spread of disease to any one of the following:

  1. Dura
  2. Jugular bulb, sigmoid sinus
  3. Carotid artery
  4. Petrous apex extension

The advantage of this Manolidis system is that it takes into account the spread of cancer from the auricle to the ear canal. It also considers progressively deeper sites as higher levels of staging. Furthermore, this staging system does not require measurement of tissue depth for adequate staging.

One disadvantage of the system is that infratemporal fossa and temporomandibular joint involvement are considered as an early stage finding, which is not in keeping with the current understanding of temporal bone cancer invasion.

Pittsburgh temporal bone cancer staging system (2000)

The original classification was from Arriaga et al in 1990, described in their landmark study which correlated computed tomography findings with pathological findings.

Their staging system ranks tumors by the extent of local destruction (e.g., canal wall or soft tissue extension) and by the involvement of medial structures (e.g., ear canal, middle ear/mastoid, inner ear involvement) and uses a TNM format for squamous cell carcinoma of the external auditory meatus. In their schema, any lymph node involvement was automatically considered a sign of advanced-stage disease.

The original classification was later amended in 2000 by Moody et al to classify patients with facial paresis or paralysis as having T4 disease.

Stage Description
T Staging
T1 Limited to the EAC without bony erosion or evidence of soft tissue involvement
T2 Limited to the EAC with bone erosion (not full thickness) or limited soft tissue involvement (<0.5 cm)
T3 Erosion through the osseous EAC (full thickness) with limited soft tissue involvement (<0.5 cm) or tumor involvement in the middle ear and/or mastoid
T4 Erosion of the cochlea, petrous apex, medial wall of the middle ear, carotid canal, jugular foramen, or dura; with extensive soft tissue involvement (>0.5 cm, such as involvement of the TMJ or styloid process); or evidence of facial paresis
N Staging
N0 No regional nodes involved.
N1 Single metastatic regional node <3 cm in size
N2a Single ipsilateral node 3–6 cm in size
N2b Multiple ipsilateral metastatic lymph nodes
N2c Contralateral metastatic lymph node
N3 Metastatic lymph node >6 cm in size
Overall stage
I T1N0
IV T4N0, any T + N1-3