Oral cancer staging

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Simrat Sarai, M.D. [2]; Grammar Reviewer: Natalie Harpenau, B.S.[3]

Overview

According to the TNM staging system by the American Joint Committee on Cancer, there are four stages of oral cancer based on the tumor size, lymph nodes involved and metastasis.

Staging

The staging systems are all clinical and based on the best possible estimate of the extent of disease before treatment.
Information from diagnostic imaging studies may be used in staging.
Magnetic resonance imaging offers an advantage over computed tomographic scans in the detection and localization of head and neck tumors and in the distinction of lymph nodes from blood vessels.
If a patient relapses, complete re-staging must be done to select the appropriate additional therapy.
The stage of the disease depends on several factors:
- The size of the primary lesion
- Local extension
- Lymph node involvement
- Evidence of distant metastasis

The tumor-node metastasis (TNM) classification of oral cancer is the most widely accepted system.
This system has 3 basic clinical features:
- The size (in centimeters) of the primary tumor
- The presence, number, size, and spread (unilateral or bilateral) to the local lymph nodes
- The presence or absence of distant metastasis.

T Categories for oral cavity cancers

These measurements refer to the primary oral cancer tumor.

T Classification	Thickness
TX	Primary tumor cannot be assessed
T0	No evidence of primary tumor
Tis	Carcinoma in-situ
T1	Tumor ≤ 2 cm in greatest dimension
T2	Tumor > 2 cm but ≤ 4 cm in greatest dimension
T3	Tumor > 4 cm in greatest dimension
T4a	Moderately advanced local disease (Lip) Tumor invades through cortical bone, inferior alveolar nerve, floor of mouth, or skin of face, that is, chin or nose. (Oral cavity) Tumor invades adjacent structures only (e.g., through cortical bone [[[mandible]] or maxilla] into deep [extrinsic] muscle of tongue [[[genioglossus]], hyoglossus, palatoglossus, and styloglossus], maxillary sinus, or skin of face).
T4b	Very advanced local disease Tumor invades masticator space, pterygoid plates, or skull base and/or encases internal carotid artery

N Categories for oral cavity cancers

N Classification	Nodal Mass
NX	Regional lymph nodes cannot be assessed
N0	No regional lymph node metastasis
N1	Metastasis in a single ipsilateral lymph node, ≤ 3 cm in greatest dimension
N2	Metastasis in a single ipsilateral lymph node, > 3 cm but ≤ 6 cm in greatest dimension Metastases in multiple ipsilateral lymph nodes, none > 6 cm in greatest dimension Metastases in bilateral or contralateral lymph nodes, none > 6 cm in greatest dimension
N2a	Metastasis in single ipsilateral lymph node, > 3 cm but ≤ 6 cm in greatest dimension
N2b	Metastases in multiple ipsilateral lymph nodes, none > 6 cm in greatest dimension
N2c	Metastases in bilateral or contralateral lymph nodes, none > 6 cm in greatest dimension
N3	Metastasis in a lymph node > 6 cm in greatest dimension.

M Categories for Oral Cavity

M Classification	Definition
M0	No evidence of distant metastasis
M1	Distant metastasis

Stages of Oral cancer

Stage	T	N	M
0	Tis	N0	M0
I	T1	N0	M0
II	T2b	N0	M0
III	T3	N0	M0
	T1	N1	M0
	T2	N1	M0
	T3	N1	M0
IVA	T4a	N0	M0
	T4a	N1	M0
	T1	N2	M0
	T2	N2	M0
	T3	N2	M0
	T4a	N2	M0
IVB	AnyT	N3	M0
	T4b	AnyN	M0
IVC	AnyT	AnyN	M1

Tumor grades of oral cancer

Most head and neck cancers are of the squamous cell variety and may be preceded by various precancerous lesions.
Minor salivary gland tumors are not uncommon in these sites.
Specimens removed from the lesions may show the carcinomas to be non-invasive, in which case the term carcinoma in-situ is applied.
An invasive carcinoma will be well-differentiated, moderately well-differentiated, poorly differentiated or undifferentiated.

Tumor grading is recommended using Broder classification (Tumor Grade [G]):

Grade of Tumor(G)	Definition
G1	Well-differentiated
G2	Moderately well-differentiated
G3	Poorly differentiated
G4	Undifferentiated

No statistically significant correlation between degree of differentiation and the biologic behavior of the cancer exists; however, vascular invasion is a negative prognostic factor.

References

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