The 8th edition of the American Joint Commission on Cancer (AJCC) made several modifications to the staging of thyroid cancers.
Thyroid tumors: papillary, follicular, Hurthle cell, poorly differentiated, anaplastic
General rules for multiple tumors:
(1) Multifocal tumors are designated "(m)".
(2) TNM coding is based on the largest tumor (presumably if of the same histologic type).
Parameters:
(1) diameter in centimeters
(2) gross extrathyroid spread
(3) metastases to regional lymph nodes
(4) distant metastases
Diameter in cm |
Extrathyroid Extension |
T Code |
<= 1 cm |
no |
T1a |
1.01 to 2 cm |
no |
T1b |
2.01 to 4 cm |
no |
T2 |
> 4 cm |
no |
T3a |
NA |
yes, into strap muscles |
T3b |
NA |
yes, major neck structures |
T4 |
Modifications:
(1) TX: cannot be assessed
(2) T0: no evidence of primary tumor
(3) T4a: subcutaneous soft tissue, larynx, trachea, esophagus, recurrent laryngeal nerve
(4) T4b: prevertebral fascia, carotid artery, mediastinal blood vessels
where:
• Strap muscles inlcude the sernohyoid, sternothyroid, thyrohyoid and omohyoid muscles.
• Microscopic extension beyond the thyroid is not included in decision-making.
Nodal Metastases |
N Code |
cannot be assessed |
NX |
none |
N0 |
any |
N1 |
Modifications:
(1) N0a: by cytology or histology
(2) N0b: by imaging studies or clinical exam
(3) N1a: unilateral or bilateral involvement of VI or VII lymph nodes (pretracheal, paratracheal, prelaryngeal, upper mediastinal)
(4) N1b: unilateral or bilateral involvement of I, II, III, IV or V level lymph nodes; retropharyngeal lymph nodes
Distant Metastases |
M Code |
no |
M0 |
yes |
M1 |
Specialty: Hematology Oncology, Surgery, general, Endocrinology