TNM staging criteria of thyroid cancer
T is the size of the primary tumor, N is whether there is metastasis in regional lymph nodes, and M is whether there is distant metastasis. Specifically, the TNM staging criteria of thyroid cancer are as follows
Primary tumor(T)
Note: All classifications can be subdivided into: a, isolated tumor; b, multifocal tumor (the largest of which determines the staging)
TX Primary tumor cannot be assessed
T0 No evidence of primary tumor
T1 Tumor ≤2 cm in maximum diameter, confined to the thyroid gland
T2 Tumor >2cm, but ≤4cm, confined to the thyroid gland
T3 Tumor >4cm in size, confined to the thyroid gland or any tumor with minimal extrathyroidal invasion (e.g. sternal thyroid muscle or soft tissue around the thyroid gland)
T4a tumor, regardless of size, is beyond the thyroid envelope and invades subcutaneous soft tissue, larynx, trachea, esophagus or laryngeal nerve
T4b Tumor invades the prevertebral fascia or encircles the carotid artery or mediastinal vessels
All undifferentiated carcinomas are T4 tumors
T4a Undifferentiated carcinoma confined to the thyroid gland – surgically resectable
T4b Undifferentiated carcinoma with extra-thyroidal invasion – surgically unresectable
Regional lymph nodes (N)
Regional lymph nodes are median, lateral cervical and superior mediastinal lymph nodes in the neck
NX Regional lymph nodes could not be evaluated
N0 No regional lymph node metastasis
N1 Regional lymph node metastasis
N1a Group VI metastases (pre-tracheal, paratracheal, and anterior laryngeal/Delphian lymph nodes)
N1b Metastasis to unilateral, bilateral, or contralateral cervical or upper mediastinal lymph nodes
Distant metastasis (M)
MX Distant metastases could not be assessed
M0 No distant metastasis
M1 with distant metastasis
Different clinical stages of thyroid cancer
Papillary or follicular carcinoma of the thyroid
Under 45 years old
Stage I Any T Any N M0
Stage II Any T Any N M1
45 years old or above
Stage I T1 N0 M0
Phase II T2 N0 M0
Phase III T3 N0 M0
T1 N1a M0
T2 N1a M0
T3 N1a M0
Phase IVA T4a N0 M0
T4a N1a M0
T1 N1b M0
T2 N1b M0
T3 N1b M0
T4a N1b M0
Phase IVB T4b Any N M0
Stage IVC Any T Any N M1
Medullary thyroid carcinoma
Stage I T1 N0 M0
Stage II T2 N0 M0
Stage III T3 N0 M0
T1 N1a M0
T2 N1a M0
T3 N1a M0
Phase IVA T4a N0 M0
T4a N1a M0
T1 N1b M0
T2 N1b M0
T3 N1b M0
T4a N1b M0
Phase IVB T4b Any N M0
Stage IVC Any T Any N M1
Undifferentiated (interstitial) carcinoma
All interstitial carcinomas are stage IV
Stage IVA T4a Any N M0
Stage IVB T4b Any N M0
Stage IVC Any T Any N M1