TNM Staging
Feb 21, 2009
Traditionally, patients have had the impression that tumors are staged on a scale I (best prognosis) through IV (worst prognosis). While this has been true in the past, it has also been found that generic terms like stage I, II, III, or IV are not useful in planning treatment nor does it give enough information to all the members of the healthcare team who may participate in a patient's care. Therefore, in 1988, a committee called the American Joint Committee on Cancer was established to address this issue. This committee created a new method of staging for cancers throughout the body and fine tuned the staging methodology for the head and neck. TNM staging can still be converted to the traditional stage I-IV, but most physicians now talk of tumors in terms of their TNM staging.
The T in TNM stands for tumor. Tumors are graded on a scale of 0-4. T0 means that there is no evidence of the primary tumor at the time of diagnosis (an unusual but not uncommon occurrence). T4 usually refers to later, more invasive and larger tumors which involve adjacent structures, including the muscles, neck, etc. The "T-staging" varies for different parts of the head and neck. For example, tumors of the oral cavity (the region in the mouth from the lips to the tonsils) are staged as T1 if the tumors are 0 to 2 cm. in size, T2 if they are 2-4 cm. in size, T3 if they are greater than 4 cm. in size, and T4 if there is nerve involvement, involvement of bone, or extensive spread of tumor. However, this cannot be applied to all regions of the head and neck.
The N in TNM refers to node status. The "N-staging" is used for all types of head and neck cancers. The "N-staging" ranges from N0 (no evidence of nodal metastasis) to N3 (extensive nodal disease usually greater than 6 cm. in size). N1 refers to metastasis into lymph nodes which are on the same side as the primary tumor and which are smaller than 3 cm. N2 refers to tumors that are 3 to 6 cm. in size. The N2 classification is further broken down to A, B, and C. N2A refers to tumors on the same side as the primary tumor, measuring 3-6 cm. in size. N2B refers to tumors with nodes in several different areas of the neck but none greater than 6 cm. and all on the same side as the primary tumor. N2C refers to lymph nodes on the opposite side of the neck from the primary tumor or on both sides of the neck. N3, then, generally refers to massive nodal disease, which usually signifies a late stage or extensive nodal metastasis.
The M in TNM staging refers to metastasis or distant metastasis. M0 means that there is no evidence of distance metastasis at the time of initial presentation and M1 means that there is evidence of metastasis to any other site in the body outside of the head and neck.
The TNM staging, while sometimes quite difficult for the lay person to understand, is very useful to practicing head and neck oncologists in that it provides a common language for head and neck oncologists to communicate with when discussing cancer patients. It is still possible to break down the TNM staging into the traditional stage I-IV tumor staging system for patients; however, most patients will most likely hear their tumors described with TNM staging. The prognosis for each TNM stage varies based on the location of the primary. For each "T-stage", however, the presence or absence of nodal disease is highly significant in the prognosis. The worst prognostic sign in cancers of the head and neck (and most commonly squamous cell carcinoma) is the presence of nodal metastasis. While the presence of nodal metastasis is by no means a hopeless situation, lymph node metastasis does imply later disease, and more aggressive treatment is usually indicated.
The T in TNM stands for tumor. Tumors are graded on a scale of 0-4. T0 means that there is no evidence of the primary tumor at the time of diagnosis (an unusual but not uncommon occurrence). T4 usually refers to later, more invasive and larger tumors which involve adjacent structures, including the muscles, neck, etc. The "T-staging" varies for different parts of the head and neck. For example, tumors of the oral cavity (the region in the mouth from the lips to the tonsils) are staged as T1 if the tumors are 0 to 2 cm. in size, T2 if they are 2-4 cm. in size, T3 if they are greater than 4 cm. in size, and T4 if there is nerve involvement, involvement of bone, or extensive spread of tumor. However, this cannot be applied to all regions of the head and neck.
The N in TNM refers to node status. The "N-staging" is used for all types of head and neck cancers. The "N-staging" ranges from N0 (no evidence of nodal metastasis) to N3 (extensive nodal disease usually greater than 6 cm. in size). N1 refers to metastasis into lymph nodes which are on the same side as the primary tumor and which are smaller than 3 cm. N2 refers to tumors that are 3 to 6 cm. in size. The N2 classification is further broken down to A, B, and C. N2A refers to tumors on the same side as the primary tumor, measuring 3-6 cm. in size. N2B refers to tumors with nodes in several different areas of the neck but none greater than 6 cm. and all on the same side as the primary tumor. N2C refers to lymph nodes on the opposite side of the neck from the primary tumor or on both sides of the neck. N3, then, generally refers to massive nodal disease, which usually signifies a late stage or extensive nodal metastasis.
The M in TNM staging refers to metastasis or distant metastasis. M0 means that there is no evidence of distance metastasis at the time of initial presentation and M1 means that there is evidence of metastasis to any other site in the body outside of the head and neck.
The TNM staging, while sometimes quite difficult for the lay person to understand, is very useful to practicing head and neck oncologists in that it provides a common language for head and neck oncologists to communicate with when discussing cancer patients. It is still possible to break down the TNM staging into the traditional stage I-IV tumor staging system for patients; however, most patients will most likely hear their tumors described with TNM staging. The prognosis for each TNM stage varies based on the location of the primary. For each "T-stage", however, the presence or absence of nodal disease is highly significant in the prognosis. The worst prognostic sign in cancers of the head and neck (and most commonly squamous cell carcinoma) is the presence of nodal metastasis. While the presence of nodal metastasis is by no means a hopeless situation, lymph node metastasis does imply later disease, and more aggressive treatment is usually indicated.
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