adenoid cystic carcinoma is staged using the TNM system for salivary gland tumors. If the tumor originates from a major salivary gland, the staging system for a major salivary gland tumor is used. If the tumor originates from a minor salivary gland, the TNM staging system used for the location or primary site is used. For example, an adenoid cystic carcinoma that arises from a salivary gland in the palate will be staged according to the TNM staging system for the oral cavity. Doctors use the results from diagnostic tests and scans to answer these questions:
- Tumor (T): How large is the primary tumor? Where is it located?
- Node (N): Has the tumor spread to the lymph nodes? If so, where and how many?
- Metastasis (M): Has the cancer spread to other parts of the body? If so, where and how much?
The results are combined to determine the stage of cancer for each person. There are 5 stages: stage 0 (zero) and stages I through IV (1 through 4). The stage provides a common way of describing the cancer so doctors can work together to plan the best treatments.
Staging can be clinical or pathological. Clinical staging is based on the results of tests done before surgery, which may include physical examinations and imaging tests. Pathological staging is based on what is found during surgery, including biopsy. In general, pathological staging provides the most information to determine a patient’s prognosis.
Here are more details on each part of the TNM system:
Using the TNM system, the “T” plus a letter or number (0 to 4) is used to describe the size and location of the tumor. Tumor size is measured in centimeters (cm). A centimeter is roughly equal to the width of a standard pen or pencil.
Stage may also be divided into smaller groups that help describe the tumor in even more detail. Specific tumor stage information is listed below.
TX: The primary tumor cannot be evaluated.
T0 (T plus zero): No evidence of a tumor is found.
T1: The tumor is small, 2 centimeters (cm) at its widest dimension. It is also noninvasive, which means it has not grown outside the area where it began.
T2: The tumor is larger, between 2 cm and 4 cm, but noninvasive.
T3: The tumor is larger than 4 cm, but not larger than 6 cm, and has spread beyond the salivary gland. However, the tumor does not affect the seventh nerve, which is the facial nerve that controls such expressions as smiles or frowns.
T4a: The tumor has invaded the skin, jawbone, ear canal, and/or facial nerve.
T4b: The tumor has invaded the skull base and/or the nearby bones and/or encases the arteries.
The “N” in the TNM staging system is for lymph nodes, the small, bean-shaped organs help fight infection. For adenoid cystic carcinoma, lymph nodes near the head and neck are called regional lymph nodes. Lymph nodes in other parts of the body are called distant lymph nodes.
NX: The neck has undergone an intervention that prevents the evaluation of lymph nodes.
N0: There is no evidence of cancer in the regional nodes.
N1: The cancer has spread to a single node on the same side as the primary tumor, and the cancer found in the node is 3 cm or smaller.
N2a: The cancer has spread to a single lymph node on the same side as the primary tumor and is larger than 3 cm, but not larger than 6 cm.
N2b: The cancer has spread to more than one lymph node on the same side as the primary tumor, and no tumor measures larger than 6 cm.
N2c: The cancer has spread to more than one lymph node on either side of the body, and no tumor measures larger than 6 cm.
N3: The cancer found in the lymph nodes is larger than 6 cm.
The “M” in the TNM system describes cancer that has spread to other parts of the body, called distant metastasis.
MX: Distant metastasis cannot be evaluated.
M0: The cancer has not spread to other parts of the body.
M1: The cancer has spread to other parts of the body.
Cancer stage grouping
Doctors assign the stage of the cancer by combining the T, N, and M classifications.
Stage I: This stage describes a noninvasive tumor (T1 or T2) with no spread to lymph nodes (N0) and no distant metastasis (M0).
Stage II: This stage describes an invasive tumor (T3) with no spread to lymph nodes (N0) or distant metastasis (M0).
Stage III: This stage describes a smaller tumor (T1 or T2) that has spread to regional lymph nodes (N1) but shows no sign of metastasis (M0).
Stage IVA: This stage describes any invasive tumor (T4a) that either has no lymph node involvement (N0) or has spread to only a single, same-sided lymph node (N1), but with no metastasis (M0). It is also used to describe a T3 tumor with one-sided nodal involvement (N1) but no metastasis (M0), or any tumor (any T) with extensive nodal involvement (N2) but no metastasis (M0).
Stage IVB: This stage describes any cancer (any T) with more extensive spread to lymph nodes (N2 or N3) and no metastasis (M0).
Stage IVC: This stage describes any cancer (any T, any N) with distant metastasis (M1).
Recurrent: Recurrent cancer is cancer that has come back after treatment. If the cancer does return, there will be another round of tests to learn about the extent of the recurrence. These tests and scans are often similar to those done at the time of the original.