Old and New Insights in the Treatment of Thyroid Carcinoma

Table 4

TNM classification system for thyroid carcinoma.

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TNM Classification System

T1 Tumor diameter 2 cm or smaller

T2 Primary tumor diameter $>$ 2 to 4 cm.

T3

Primary tumor diameter $>$ 4 cm limited to the thyroid or with

minimal extracapsular

extension

T4a

Tumor of any size extending beyond the thyroid capsule to

invade the subcutaneous soft

tissues, larynx, trachea, esophagus, or recurrent laryngeal nerve

T4b Tumor invades prevertebral fascia or encases carotid artery

or mediastinal nerves

Tx Primary tumor size unknown, but without extrathyroid

extension

N0 No metastatic nodes

N1a Metastasis to level VI (pretracheal, paratracheal, prelaryngeal)

NIb Metastasis to unilateral or bilateral or contralateralcervical

or superior mediastinum

Nx Nodes not assessed at surgery

M0 No distant metastasis

M1 Distant metastasis

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