Supraglottis

T1: Tumor limited to one subsite of supraglottis with normal vocal cord mobility
T2: Tumor invades mucosa of more than one adjacent subsite of supraglottis or glottis or region outside the supraglottis eg, mucosa of base of tongue, vallecula, medial wall of pyriform sinus) without fixation of the larynx
T3: Tumor limited to larynx with vocal cord fixation and/or invades any of the following: postcricoid area, preepiglottic tissues, paraglottic space, and/or minor thyroid cartilage erosion (eg, inner cortex)
T4a: Tumor invades through the thyroid cartilage and/or invades tissues beyond the larynx (eg, trachea, soft tissues of neck including deep extrinsic muscle of the tongue, strap muscles, thyroid, or esophagus)
T4b: Tumor invades prevertebral space, encases carotid artery, or invades mediastinal structures

Glottis

T1: Tumor limited to the vocal cord(s) (may involve anterior or posterior commissure) with normal mobility
  T1a: Tumor limited to one vocal cord
  T1b: Tumor involves both vocal cords
T2: Tumor extends to supraglottis and/or subglottis, and/or with impaired vocal cord mobility
T3: Tumor limited to the larynx with vocal cord fixation and/or invades paraglottic space, and/or minor thyroid cartilage erosion (eg, inner cortex)
T4a: Tumor invades through the thyroid cartilage and/or invades tissues beyond the larynx (eg, trachea, soft tissues of neck including deep extrinsic muscle of the tongue, strap muscles, thyroid, or esophagus)
T4b: Tumor invades prevertebral space, encases carotid artery, or invades mediastinal structures

Nx:: Regional lymph nodes cannot be assessed
N): No regional lymph node metastasis
N1: Metastasis in a single ipsilateral lymph node, 3 cm or less in greatest dimension
N2: Metastasis in a single ipsilateral lymph node, more than 3 cm but not more than 6 cm in greatest dimension; or in multiple ipsilateral lymph nodes, none more than 6 cm in greatest dimension, or in bilateral or contralateral lymph nodes, none more than 6 cm in greatest dimension
  N2a: Metastasis in single ipsilateral lymph node, more than 3 cm but not more than 6 cm in greatest dimension
  N2b: Metastasis in multiple ipsilateral lymph nodes, none more than 6 cm in greatest dimension
  N2c: Metastasis in bilateral or contralateral lymph nodes, none more than 6 cm in greatest dimension
N3: Metastasis in a lymph node, more than 6 cm in greatest dimension

Stage 0: Tis N0 M0
Stage I: T1 N0 M0
Stage II: T2 N0 M0
Stage III: T3 N0 M0, T1 N1 M0, T2 N1 M0, T3 N1 M0
Stage IVa: T4a N0 M0, T4a N1 M0, T1 N2 M0, T2 N2 M0, T3 N2 M0, T4a N2 M0
Stage IVb: T4b Any N M0, Any T N3 M0
Stage IVc: Any T Any N M1