Stage Information for Oropharyngeal Cancer
Note: The American Joint Committee on Cancer has recently published a new edition of the AJCC Cancer Staging Manual, which includes revisions to the staging for this disease. The PDQ Adult Treatment Editorial Board, which is responsible for maintaining this summary, is currently reviewing the new staging to determine the changes that need to be made in the summary. In addition to updating this Stage Information section, additional changes may need to be made to other parts of this summary to ensure that it is up-to-date. The changes will be made as soon as possible.
The staging systems for oropharyngeal cancer are all clinical, 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 indirect mirror examination. The appropriate nodal drainage areas are examined by careful palpation.
The tumor must be confirmed histologically, and any other pathologic data obtained from a biopsy may be included. Additional radiographic studies may be included. As an adjunct to clinical examination, magnetic resonance imaging is used to evaluate the extent of disease in the soft tissues; computed tomography is used to evaluate the mandible and maxilla. Positron emission tomography has been investigated as an imaging modality for recurrent oropharyngeal cancer.
Complete endoscopy, typically under general anesthesia, is performed after completion of other staging studies to assess the surface extent of the tumor accurately, to assess deep involvement by palpation for muscle invasion, and to facilitate biopsy. Because of the incidence of multiple primary tumors occurring simultaneously, a careful search for other primary tumors of the upper aerodigestive tract is indicated.
Definitions of TNM
The American Joint Committee on Cancer has designated staging by TNM classification to define oropharyngeal cancer. Nonepithelial tumors such as those of lymphoid tissue, soft tissue, bone, and cartilage are not included.
Table 1. Primary Tumor (T)a
a Reprinted with permission from AJCC: Pharynx. In: Edge SB, Byrd DR, Compton CC, et al., eds.: AJCC Cancer Staging Manual. 7th ed. New York, NY: Springer, 2010, pp 41-56.
b Mucosal extension to lingual surface of epiglottis from primary tumors of the base of the tongue and vallecula does not constitute invasion of larynx.
|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 or extension to lingual surface of epiglottis.|
|T4a||Moderately advanced local disease. Tumor invades the larynx, extrinsic muscle of tongue, medial pterygoid, hard palate, or mandible.b|
|T4b||Very advanced local disease. Tumor invades lateral pterygoid muscle, pterygoid plates, lateral nasopharynx, or skull base, or encases carotid artery.|