Stage
The stage of a cancer is determined by the TNM staging system:
- The ‘T’ stands for tumor size.
- The ‘N’ stands for lymph node involvement.
- The ‘M’ stands for distant metastases, or cancer spread to other areas of the body.
Staging helps doctors determine how serious the cancer is and how best to treat it. Staging systems often reference very specific anatomical structures. Please reference the anatomy page to learn more about these terms.
Staging of oropharyngeal squamous cell carcinoma is based on whether the cancer is HPV-mediated and whether it is p16 positive or negative.
HPV-Mediated p16+ Oropharyngeal Cancer
Clinical Staging Table
T N M Stage T0, T1 or T2 N0 or N1 M0 I T0, T1 or T2 N2 M0 II T3 N0, N1, or N2 M0 II T0, T1, T2, T3 or T4 N3 M0 III T4 N0,N1, N2 or N3 M0 III Any T Any N M1 IV
Pathologic Staging Table
T N M Stage T0, T1 or T2 N0 or N1 M0 I T0, T1, or T2 N2 M0 II T3 or T4 N0 or N1 M0 II T3 or T4 N2 M0 III Any T Any N M1 IV
Primary Tumor Staging Definitions
T Definition T0 There is no evidence of a primary tumor. T1 The tumor is 2 cm or smaller at its largest point. T2 The tumor is more than 2 cm but not more than 4 cm at its largest point. T3 The tumor is more than 4 cm at its largest point or extends to the lingual surface of the epiglottis. T4 This is moderately advanced local disease. The tumor invades the larynx, muscles of tongue, medial pterygoid, hard palate, jaw or beyond.
Regional Lymph Nodes Clinical N (cN) Staging Definitions
N Definition NX The neck lymph nodes cannot be assessed. N0 No regional lymph node metastases. N1 One or more lymph nodes on the same side as the primary tumor, none being larger than 6 cm. N2 One or more lymph nodes on the opposite side as the primary tumor (or both sides), none being larger than 6 cm. N3 Lymph nodes that are larger than 6 cm.
Regional Lymph Nodes Pathologic N (pN) Staging Definitions
N Definition NX The neck lymph nodes cannot be assessed. N0 No regional lymph node metastases. N1 4 or fewer positive lymph nodes. N2 More than 4 positive lymph nodes.
Distant Metastasis Staging Definitions
| M | Definition |
| M0 | No evidence of distant spread |
| M1 | Evidence of distant spread |
Oropharyngeal Cancer (p16-)
Pathologic Staging Table
T N M Stage Tis N0 M0 0 T1 N0 M0 I T2 N0 M0 II T3 N0 M0 III T1, T2, T3 N1 M0 III T4a N0 or N1 M0 IVA T1, T2, T3, T4a N2 M0 IVA Any T N3 M0 IVB T4b Any N M0 IVB Any T Any N M1 IVC
Primary Tumor Staging Definitions
T Definition Tx The primary tumor cannot be assessed. Tis Carcinoma in situ, meaning that there are cancer type cells, but they have not yet invaded deep into tissue. T1 The primary tumor is 2 cm or smaller at its largest point. T2 The primary tumor is more than 2 cm but not more than 4 cm at its largest point. T3 The primary tumor is more than 4 cm at its largest point or extends to the surface of epiglottis. T4a This is moderately advanced local disease. The primary tumor invades the larynx, muscles of tongue, medial pterygoid, hard palate, lower jaw or beyond. T4b This is very advanced local disease. The primary tumor invades the muscles of tongue or masticator space, pterygoid plates, part of the nasopharynx, skull base, or carotid artery.
Regional Lymph Nodes Clinical N (cN) Staging Definitions
N Definition NX The neck lymph nodes cannot be assessed. N0 No regional lymph node metastases. N1 One lymph node on the same side as the primary tumor that is less than 3 cm and ENE (-) N2a One lymph node on the same side as the primary tumor that is more than 3 cm, but less than 6 cm and ENE (-) N2b Multiple lymph nodes on the same side as the primary tumor, none larger than 6 cm and ENE (-) N2c Multiple lymph nodes on the opposite side as the primary tumor (or both sides), none being larger than 6 cm and ENE (-) N3a One positive lymph node that is larger than 6 cm and ENE (-) N3b Any number of positive lymph nodes with clinically visible ENE (+)
Regional Lymph Nodes Pathologic N (pN) Staging Definitions
N Definition NX The neck lymph nodes cannot be assessed. N0 No regional lymph node metastases. N1 One lymph node on the same side as the primary tumor that is less than 3 cm and ENE (-). N2a One positive lymph node that is less than 3 cm and ENE (+) orOne lymph node on the same side as the primary tumor that is larger than 3 cm, but less than 6 cm and ENE (-) N2b Multiple lymph nodes on the same side as the primary tumor, none larger than 6 cm and ENE (-) N2c Multiple lymph nodes on the opposite side as the primary tumor (or both sides), none larger than 6 cm and ENE (-) N3a One positive lymph node that is larger than 6 cm and ENE (-) N3b One lymph node on the same side as the primary tumor that is larger than 3 cm and ENE (+) orMultiple lymph nodes that are on the same side, the opposite side or both sides with ENE (+)
ENE (+): Extranodal extension is present (tumor has spread outside of the lymph node based on examination of tumor under the microscope).
ENE (-): Extranodal extension is absent (tumor has not spread outside of the lymph node based on examination of tumor under the microscope).
Distant Metastasis Staging Definitions
M Definition M0 No evidence of distant spread. M1 Evidence of distant spread,
