TNM system for oral cancer
Making an educated treatment decision begins with the stage, or progression, of the disease. The stage of oral cancer is one of the most important factors in evaluating treatment options.
Our cancer doctors use a variety of diagnostic tests to evaluate oral cancer and develop an individualized treatment plan. If you have been recently diagnosed, we will review your pathology to confirm you have received the correct diagnosis and staging information, and develop a personalized treatment plan. If you have a recurrence, we will perform comprehensive testing and recommend a treatment approach that is personalized to you and your cancer type and stage.
We stage oral cancer using the American Joint Committee on Cancer’s TNM system, a commonly accepted method based on three key components:
- Tumor (T), which describes the size of the original tumor
- Node (N), which indicates whether the cancer is present in the lymph nodes
- Metastasis (M), which refers to whether cancer has spread to other parts of the body
A number (0-4) or the letter X is assigned to each factor. A higher number indicates increasing severity. For instance, a T1 score indicates a smaller tumor than a T2 score. The letter X means the information could not be assessed.
Once the T, N, and M scores have been assigned, an overall stage is determined.
T categories for oral cavity cancer
These measurements refer to the primary oral cancer tumor.
TX: Primary tumor cannot be assessed; information not known.
TO: No evidence of a primary tumor has been found.
Tis: Carcinoma in situ has been diagnosed, meaning the disease is still localized, or contained within the top layers of cells lining the oral cavity. Cancer cells have not invaded the deeper layers of oral tissue.
T1: Tumor is 2 cm across or smaller.
T2: Tumor is larger than 2 cm across, but smaller than 4 cm.
T3: Tumor is larger than 4 cm across.
T4 is divided into two subgroups:
- T4a: The tumor is growing into nearby structures. At this stage, the oral cancer is called a moderately advanced local disease. The areas to which cells have spread vary according to the type of oral cancer:
- For oral cavity cancers, the tumor is growing into nearby structures such as the bones of the jaw or face, deep muscle of the tongue, skin of the face, or maxillary sinus.
- For lip cancers, the tumor is growing into nearby bone, the inferior alveolar nerve (the nerve to the jawbone), the floor of the mouth, or the skin of the chin or nose.
- T4b: The tumor has grown through nearby structures and into deeper areas or tissues. At this stage, the cancer is called very advanced local disease, and may include any of the following conditions:
- The tumor is growing into other bones, such as the pterygoid plates (in the skull) and/or the skull base. This type of spreading can occur with any oral cancer.
- The tumor surrounds the internal carotid artery. This type of spreading may occur with any oral cancer.
- For lip and oral cavity cancers: The tumor is growing into an area called the masticator space.
N categories for oral cavity cancers
NX: Nearby lymph nodes cannot be assessed; information not known.
N0: The oral cancer has not spread to any nearby lymph nodes.
N1: The cancer has spread to one lymph node on the same side of the head or neck as the primary tumor. This lymph node is smaller than 3 cm across.
N2 is divided into three subgroups:
- N2a: The oral cancer has spread to one lymph node on the same side as the primary tumor, and the lymph node measures 3–6 cm across.
- N2b: The cancer has spread to two or more lymph nodes on the same side as the primary tumor. No lymph nodes are larger than 6 cm across.
- N2c: The oral cancer has spread to one or more lymph nodes on both sides of the neck or on the side opposite the primary tumor. No lymph nodes are larger than 6 cm across.
- N3: The cancer has spread to a lymph node that measures more than 6 cm across.
M categories for oral cavity cancers
M0: No distant spread has been detected.
M1: The oral cancer has spread to distant sites outside the head and neck region (for example, the lungs, liver or bones).