Staging is a way of describing cancer, such as where it is located, if or where it has spread, and if it is affecting the functions of other organs in the body. Doctors use diagnostic tests to determine the cancer’s stage, so staging may not be complete until the doctor performs a biopsy. Knowing the stage helps the doctor to decide what kind of treatment is best and can help predict a patient’s prognosis (chance of recovery). There are different stage descriptions for different types of cancer.
One tool that doctors use to describe the stage is the TNM system. This system uses three criteria to judge the stage of the cancer: the tumor itself, the lymph nodes around the tumor, and if the tumor has spread to other parts of the body. The results are combined to determine the stage of cancer for each person. There are five stages: stage 0 (zero) and stages I through IV (one through four). The stage provides a common way of describing the cancer, so doctors can work together to plan the best treatments.
TNM is an abbreviation for tumor (T), node (N), and metastasis (M). Doctors look at these three factors to determine the stage of cancer:
- How large is the primary tumor and where is it located? (Tumor, T)
- Has the tumor spread to the lymph nodes? (Node, N)
- Has the cancer metastasized to other parts of the body? (Metastasis, M)
Tumor. 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. Some stages are also divided into smaller groups that help describe the tumor in even more detail. Specific tumor stage information is listed below.
TX: Indicates the primary tumor cannot be evaluated.
T0: No evidence of a tumor is found.
T1: Describes a small, noninvasive (has not spread) tumor that is 2 centimeters (cm) at its greatest dimension.
T2: Describes a larger, noninvasive tumor, between 2 cm to 4 cm.
T3: Describes a tumor that is larger than 4 cm, but not larger than 6 cm, that has spread beyond the salivary glands, but does not affect the seventh nerve, the facial nerve that controls expression such as smiles or frowns.
T4a: The tumor invades the skin, jawbone, ear canal, and/or facial nerve.
T4b: The tumor invades the skull base and/or the nearby bones and/or encases the arteries.
Node. The “N” in the TNM staging system is for lymph nodes, the tiny, bean-shaped organs that help fight infection. 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. There are many nodes located in the head and neck area, and careful assessment of lymph nodes is an important part of staging cancer of the major salivary glands.
NX: Indicates the regional lymph nodes cannot be evaluated.
N0: There is no evidence of cancer in the regional nodes.
N1: Indicates that 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.
N2: Describes any of these conditions:
N2a: 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: Cancer has spread to more than one lymph node on the same side as the primary tumor, and none measure larger than 6 cm.
N2c: Cancer has spread to more than one lymph node on either side of the body, and none measure larger than 6 cm.
N3: Cancer found in lymph nodes is larger than 6 cm.
Distant metastasis. The "M" in the TNM system describes cancer that has spread to other parts of the body.
MX: Indicates distant metastasis cannot be evaluated.
M0: Indicates the cancer has not spread to other parts of the body.
M1: Describes cancer that 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: Describes noninvasive tumors (T1, T2), with no spread to lymph nodes (N0) and no distant metastasis (M0).
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Stage II: Describes an invasive tumor (T3), with no spread to lymph nodes (N0), or distant metastasis (M0).
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Stage III: Describes smaller tumors (T1, T2) that have spread to regional lymph nodes (N1), but have no sign of metastasis (M0).
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Stage IVA: Describes any invasive tumor (T4a), with either no lymph node involvement (N0) or spread to only a single same-sided lymph node (N1), but no metastasis (M0). It is also used for a T3 tumor with one-sided nodal involvement (N1), but no metastasis (M0), or any tumor (T) with extensive nodal involvement (N2).
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Stage IVB: Describes any cancer (T), with more extensive spread to lymph nodes (N2, N3), but no metastasis (M0).
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Stage IVC: Describes any cancer with distant metastasis (M1).
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Recurrent: Recurrent cancer is cancer that comes back after treatment.
Used with permission of the American Joint Committee on Cancer (AJCC), Chicago, Illinois. The original source for this material is the AJCC Cancer Staging Manual, Sixth Edition (2002) published by Springer-Verlag New York, www.cancerstaging.net.
Histologic classification of salivary gland tumors
In addition to the stage of the cancer, doctors will classify the subtype of salivary gland tumor using a histologic evaluation (how cells look under a microscope). There are many subtypes of salivary gland cancer, and your doctor can provide more information regarding your specific diagnosis:
Benign tumor subtypes
Pleomorphic adenoma (benign mixed tumor)
Papillary cystadenoma-lymphomatosum (Warthin’s tumor)
Oncocytoma
Monomorphic adenoma
Basal cell adenoma
Glycogen-rich adenoma
Clear cell adenoma
Others
Sebaceous adenoma
Sebaceous lymphadenoma
Papillary ductal adenoma
Benign lymphoepithelial lesion
Malignant tumor subtypes
Carcinoma ex-pleomorphic adenoma
Mucoepidermoid carcinoma (including high grade, intermediate grad, and low grade)
Hybrid basal cell carcinoma-adenoid cystic carcinoma
Adenoid cystic carcinoma
Acinic cell carcinoma
Adenocarcinoma
Polymorphous low-grade adenocarcinoma
Oncocytic carcinoma (malignant oncocytoma)
Clear cell carcinoma
Epithelial-myoepithelial carcinoma of intercalated ducts
Squamous cell carcinoma
Undifferentiated carcinoma
Metastatic carcinoma
Source: Tumors of the Head and Neck, Clinical and Pathological Considerations 2nd Edition, John G. Batsakis, MD, Copyright 1979, published by The Williams & Wilkins Company.
Last Updated: October 30, 2009
