TNM Classification for Thyroid Cancer
The TNM classification for thyroid cancer is provided below. [1, 2]
Table. TNM Classification for Thyroid Cancer (Open Table in a new window)
Primary tumor (T) |
|
TX |
Primary tumor cannot be assessed |
T0 |
No evidence of primary tumor is found |
T1 |
Tumor size ≤ 2 cm in greatest dimension and is limited to the thyroid |
T1a |
Tumor ≤ 1 cm, limited to the thyroid |
T1b |
Tumor > 1 cm but ≤ 2 cm in greatest dimension, limited to the thyroid |
T2 |
Tumor size > 2 cm but ≤ 4 cm, limited to the thyroid. |
T3 |
Tumor size >4 cm, limited to the thyroid or any tumor with minimal extrathyroidal extension (eg, extension to sternothyroid muscle or perithyroid soft tissues) |
T4a |
Moderately advanced disease; tumor of any size extending beyond the thyroid capsule to invade subcutaneous soft tissues, larynx, trachea, esophagus, or recurrent laryngeal nerve |
T4b |
Very advanced disease; tumor invades prevertebral fascia or encases carotid artery or mediastinal vessel |
All anaplastic carcinomas are considered stage IV: |
|
T4a |
Intrathyroidal anaplastic carcinoma |
T4b |
Anaplastic carcinoma with gross extrathyroid extension |
Regional lymph nodes (N) |
|
Regional lymph nodes are the central compartment, lateral cervical, and upper mediastinal lymph nodes: |
|
NX |
Regional nodes cannot be assessed |
N0 |
No regional lymph node metastasis |
N1 |
Regional lymph node metastasis |
N1a |
Metastases to level VI (pretracheal, paratracheal, and prelaryngeal/Delphian lymph nodes) |
N1b |
Metastases to unilateral, bilateral, or contralateral cervical (levels I, II, III, IV, or V) or retropharyngeal or superior mediastinal lymph nodes (level VII) |
Distant metastasis (M) |
|
M0 |
No distant metastasis is found |
M1 |
Distant metastasis is present |
Table. Stage grouping (Open Table in a new window)
Stage grouping |
|||
Separate stage groupings are recommended for papillary or follicular (differentiated), medullary, and anaplastic (undifferentiated) carcinoma |
|||
Papillary and follicular thyroid cancer (age < 45y): |
|||
Stage |
T |
N |
M |
I |
Any T |
Any N |
M0 |
II |
Any T |
Any N |
M1 |
Papillary and follicular; differentiated (age ≥ 45y): |
|||
Stage |
T |
N |
M |
I |
T1 |
N0 |
M0 |
II |
T2 |
N0 |
M0 |
III |
T3 |
N0 |
M0 |
IVA |
T1-3 |
N1a |
M0 |
T4a |
N1b |
M0 |
|
IVB |
T4b |
Any N |
M0 |
IVC |
Any T |
Any N |
M1 |
Anaplastic carcinoma (all anaplastic carcinomas are considered stage IV): |
|||
Stage |
T |
N |
M |
IVA |
T4a |
Any N |
M0 |
IVB |
T4b |
Any N |
M0 |
IVC |
Any T |
Any N |
M1 |
Medullary carcinoma (all age groups): |
|||
Stage |
T |
N |
M |
I |
T1 |
N0 |
M0 |
II |
T2, T3 |
N0 |
M0 |
III |
T1-T3 |
N1a |
M0 |
IVA |
T4a |
N0 |
M0 |
T4a |
N1a |
M0 |
|
T1 |
N1b |
M0 |
|
T2 |
N1b |
M0 |
|
T3 |
N1b |
M0 |
|
T4a |
N1b |
M0 |
|
T4a |
N0, N1b |
M0 |
|
T1-T4a |
N1b |
M0 |
|
IVB |
T4b |
Any N |
M0 |
IVC |
Any T |
Any N |
M1 |