How is salivary gland cancer staged?

Staging is the process of finding out how far a cancer has spread. The stage of salivary gland cancer is one of the most important factors in selecting treatment options and estimating a patient's outlook for recovery (prognosis).

The stage of a cancer is determined from the results of physical exams, imaging tests (ultrasound, CT or MRI scan, etc.) and other tests, which are described in the section called “How is salivary gland cancer diagnosed?,” and by the results of surgery if it has been done.

The American Joint Committee on Cancer (AJCC) TNM system

A staging system is a standardized way for the cancer care team to summarize information about how far a cancer has spread. The most common system used to describe the stages of salivary gland cancers is the TNM system of the American Joint Committee on Cancer (AJCC). This system contains 3 key pieces of information:

• T describes the size of the primary tumor and whether it has invaded into nearby organs or tissues.
• N describes whether the cancer has spread to nearby (regional) lymph nodes (bean-sized collections of immune system cells located throughout the body).
• M indicates whether the cancer has metastasized (spread) to other organs of the body (The most common site of distant salivary gland cancer spread is the lungs).

Numbers or letters appear after T, N, and M to provide more details about each of these factors:

• The numbers 0 through 4 indicate increasing severity.
• The letter X means "cannot be assessed" because the information is not available.

T groups for major salivary gland cancers

TX: The main (primary) tumor cannot be assessed; information not known.

T0: No evidence of a primary tumor.

T1: Tumor is 2 cm (about ¾ inch) across or smaller. It is not growing into nearby tissues.

T2: Tumor is larger than 2 cm but no larger than 4 cm (about 1½ inch) across. It is not growing into nearby tissues.

T3: Tumor is larger than 4 cm across and/or is growing into nearby soft tissues.

T4a: Tumor is any size and is growing into nearby structures such as the jaw bone, skin, ear canal, and/or facial nerve. This is known as moderately advanced disease.

T4b: Tumor is any size and is growing into nearby structures such as the base of the skull or other bones nearby, or it surrounds the carotid artery. This is known as very advanced disease.

N groups for major salivary gland cancers

NX: Nearby (regional) lymph nodes cannot be assessed; information not known.

N0: No spread to regional lymph nodes.

N1: The cancer has spread to 1 lymph node on the same side of the head or neck as the primary tumor. The lymph node is smaller than 3 cm (about 1¼ inch) across.

N2: This group includes 3 subgroups:

• N2a: The cancer has spread to 1 lymph node on the same side as the primary tumor. The lymph node is larger than 3 cm but not larger than 6 cm (about 2½ inches) across.
• N2b: The cancer has spread to more than 1 lymph node on the same side as the primary tumor, none of the lymph nodes are larger than 6 cm across.
• N2c: The cancer has spread to 1 or more lymph nodes, none larger than 6 cm across, either on the side opposite the primary tumor or on both sides of the neck.

N3: The cancer has spread to a lymph node that is larger than 6 cm across.

M groups for major salivary gland cancers

M0: The cancer has not spread to tissues or organs far away from the salivary glands.

M1: The cancer has spread to tissues or organs far away from the salivary glands.

Stage grouping

Once the T, N, and M categories have been assigned, this information is combined in a process called stage grouping to assign an overall stage. The stage is expressed in Roman numerals from I (the least advanced) to IV (the most advanced). Some stages are subdivided with letters.

Stage I: T1, N0, M0: The tumor is no more than 2 cm (about ¾ inch) across and is not growing into nearby tissues (T1). It has not spread to nearby lymph nodes (N0) or distant sites (M0).

Stage II: T2, N0, M0: The tumor is larger than 2 cm but is no larger than 4 cm across and is not growing into nearby tissues (T2). It has not spread to nearby lymph nodes (N0) or distant sites (M0).

Stage III: Either of the following:

T3, N0, M0: The tumor is larger than 4 cm across and/or is growing into nearby soft tissues (T3). It has not spread to nearby lymph nodes (N0) or to distant sites (M0).

OR

T1 to T3, N1, M0: The tumor is any size and may have grown into nearby soft tissues (T1 to T3). The cancer has spread to one lymph node on the same side of the head or neck as the primary tumor, but the lymph node is no larger than 3 cm across (N1). The cancer has not spread to distant sites (M0).

Stage IVA: Either of the following:

T4a, N0 or N1, M0: The tumor is any size but invades nearby structures such as the jaw bone, skin, ear canal, and/or facial nerve (T4a). It may or may not have spread to one lymph node (no larger than 3 cm across) on the same side of the head or neck as the primary tumor (N0 or N1). The cancer has not spread to distant sites (M0).

OR

T1 to T4a, N2, M0: The tumor is any size and may or may not invade nearby soft tissues or structures such as the jaw bone, skin, ear canal, and/or facial nerve (T1 to T4a). The cancer has spread to more than one lymph node, to a lymph node larger than 3 cm across, or to lymph nodes on the other or both sides of the neck. None of the lymph nodes are larger than 6 cm across (N2). The cancer has not spread to distant sites (M0).

Stage IVB: Either of the following:

T4b, Any N, M0: The tumor is any size and invades nearby structures such as the base of the skull or other bones nearby, or it surrounds the carotid artery (T4b). The cancer may or may not have spread to nearby lymph nodes (any N). It has not spread to distant sites (M0).

OR

Any T, N3, M0: The tumor is any size and may or may not have invaded nearby soft tissues or other structures (any T). The cancer has spread to at least 1 lymph node that is larger than 6 cm across (N3). It has not spread to distant sites (M0).

Stage IVC: Any T, Any N, M1: The tumor is any size and may or may not have invaded nearby soft tissues or other structures (any T). The cancer may or may not have spread to nearby lymph nodes (any N). It has spread to distant sites (M1).

If you have any questions about the stage of your cancer or how it affects your treatment, be sure to ask your cancer care team.