Epithelial tumors are classified according to the guidelines set by the International Union Against Cancer (UICC) (3,4).
The T classification represents the extent of the primary tumor.
- T1 – Tumor is limited to one side of the supraglottis with normal mobility of the vocal cord(s).
- T2 – Tumor invades the vocal cord without fixation of the larynx.
- T3 – Tumor is limited to the larynx with fixation of the vocal cord and/or infiltration of the postcricoid area, pre-epiglottic tissues or most likely erosion of thyroid cartilage.
- T4a – Tumor invades through thyroid cartilage or down into the trachea and soft tissue contents of the neck.
- T4b – Tumor invades prevertebral space, mediastinal structures or encases carotid artery.
- T1 – Tumor limited to vocal cord(s) with normal mobility.
- a - Tumor limited to one vocal cord.
- b - Tumor involves both vocal cords.
- T2 – Tumor extends to supraglottis and/or subglottis, and/or with impaired vocal cord mobility.
- T3 – Tumor limited to larynx with vocal cord fixation and/or invades paraglottic space or with probable thyroid cartilage erosion.
- T4a – Tumor invades through thyroid cartilage, the trachea, soft tissues of the neck/tongue.
- T4b – Tumor invades prevertebral space, mediastinal structures, or carotid artery.
The N classification represents spreading to regional lymph nodes on the neck. The widest diameter is measured.
- N0 – no regional lymph node metastases
- N1 – single ipsilateral lymph node metastasis ≤ 3 cm
- a – single ipsilateral lymph node metastasis > 3 cm ≤ 6 cm
- b – multiple ipsilateral lymph node metastases ≤ 6 cm
- c – bilateral or contralateral lymph node metastases ≤ 6 cm
- N3 – lymph node metastases > 6 cm
The M classification represents distant metastases.
- M0 – no distance metastases
- M1 – distant metastases