Oral cancer staging: Difference between revisions
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===Stages of Oral cancer=== | ===Stages of Oral cancer===<ref>{{Cite web | title =NIH Oral cancer staging| url =http://www.cancer.gov/types/head-and-neck/hp/lip-mouth-treatment-pdq#section/_18 }}</ref> | ||
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Revision as of 05:08, 9 September 2015
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Oral cancer Microchapters |
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Diagnosis |
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Treatment |
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Case Studies |
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Oral cancer staging On the Web |
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American Roentgen Ray Society Images of Oral cancer staging |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1];Associate Editor(s)-in-Chief: Simrat Sarai, M.D. [2]
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 staging and are based on the best possible estimate of the extent of disease before treatment. The assessment of the primary tumor is based on inspection and palpation when possible and by both indirect mirror examination and direct endoscopy when necessary. The tumor must be confirmed histologically, and any other pathologic data obtained on biopsy may be included. The appropriate nodal drainage areas are examined by careful palpation. 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 restaging 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 most widely accepted protocol. 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
- 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
| 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===[1]
| 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 noninvasive, 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.