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 |
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Table. TNM Classification for Thyroid Cancer
| 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
| 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 |
