TNM system for staging

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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 tumor, including whether the cancer has grown into the wall of the esophagus or nearby tissue, and if so, how deep. 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: The primary tumor cannot be evaluated.

T0: There is no cancer in the esophagus.

Tis: This is called carcinoma (cancer) in situ. Carcinoma in situ is very early cancer. Cancer cells are in only one small area of the top lining of the esophagus without any spread into the lining.

T1: There is a tumor in the lamina propria and submucosa (the two inside layers of the esophagus). Cancer cells have spread into the lining of the esophagus.

T2: The tumor is in the muscularis propria (the third layer of the esophagus). Cancer cells have spread into but not through the muscle wall of the esophagus.

T3: The tumor is in the adventitia (the outer layer of the esophagus). Cancer cells have spread through the entire muscle wall of the esophagus into surrounding tissue.

T4: The tumor has spread outside the esophagus into areas around it. Cancer cells have spread to structures surrounding the esophagus, including the aorta (large blood vessel coming from the heart), windpipe, diaphragm, and pleural lining of the lung.

Node. The “N” in the TNM staging system stands for lymph nodes, the tiny, bean-shaped organs that help fight infection. In esophageal cancer, lymph nodes near the esophagus and in the chest are called regional lymph nodes. Lymph nodes in other parts of the body are called distant lymph nodes.

NX: The lymph nodes cannot be evaluated.

N0: The cancer was not found in any lymph nodes.

N1: The cancer has spread to one or two lymph nodes in the chest, near the tumor.

N2: The cancer has spread to three to six lymph nodes in the chest, near the tumor.

N3: The cancer has spread to seven or more lymph nodes in the chest, near the tumor.

Distant metastasis. The "M" in the TNM system indicates whether the cancer has spread to other parts of the body.

MX: Metastasis cannot be evaluated.

M0: The cancer has not spread to other parts of the body.

M1: The cancer has spread to another part of the body.

Grading

Tumor grade. Grade may also be used to describe the tumor, using the letter “G,” in addition to the TNM system. Grade is determined based on how similar the tumor cells are to healthy cells when viewed under a microscope. Healthy tissue usually has different types of cells grouped together (also called differentiated tissue). Tissue that is cancerous usually is made up of cells that look more like each other. In general, the more differentiated the tissue, the better the prognosis.

G1: The tissue looks more like healthy cells (well differentiated).

G2: The cells are somewhat different than healthy cells (somewhat differentiated).

G3: The tumor cells barely look like healthy cells (poorly differentiated).

G4: The cancer cells look almost alike and do not look like healthy cells (not differentiated).

Cancer stage grouping

Doctors assign the stage of the cancer by combining the T, N, and M classifications. There are separate staging systems for the two most common types of esophageal cancer: squamous cell carcinoma and adenocarcinoma. The staging system for each is described below.

Staging of squamous cell carcinoma of the esophagus

In addition to the TNM classifications, for squamous cell carcinoma, the stages may be subdivided based on the location of the original tumor (the upper, middle, or lower section of the esophagus), as well as the grade (G) of the tumor cells.

Stage 0: This is the same as Tis cancer, in which cancer is found in only the top lining of the esophagus (Tis, N0, M0, G1).

Stage IA: This is the same as T1 cancer, in which the cancer is located in only the two inside layers of the esophagus (T1, N0, M0, G1).

Stage IB: Either of these two conditions:

The cancer is located in only the two inside layers of the esophagus, but the tumor cells are less differentiated (T1, N0, M0, G2 or G3).

The tumor is located in the lower part of the esophagus, and the cancer has spread to either of the two outer layers of the esophagus, but not to the lymph nodes or other parts of the body (T2 or T3, N0, M0, G1).

Stage IIA: Either of these two conditions:

The tumor is located in the upper or middle part of the esophagus, and the cancer is in either of the two outer layers of the esophagus (T2 or T3, N0, M0, G1).

The tumor is located in the lower part of the esophagus, and the cancer is in either of the two outer layers of the esophagus. The tumor cells are less differentiated (T2 or T3, N0, M0, G2 or G3).

Stage IIB: Either of these two conditions:

The tumor is located in the upper or middle part of the esophagus, and cancer is in either of the two outer layers of the esophagus. The tumor cells are less differentiated (T2 or T3, N0, M0, G2 or G3).

Cancer is in the inner layers of the esophagus and has spread to one or two lymph nodes near the tumor (T1 or T2, N1, M0, any G).

Stage IIIA: Any of these three conditions:

Cancer is in the inner layers of the esophagus and has spread to three to six lymph nodes near the tumor (T1 or T2, N2, M0, any G).

Cancer is in the outside layer of the esophagus and has spread to one or two lymph nodes (T3, N1, M0, any G).

Cancer has spread beyond the esophagus to nearby tissue but not to lymph nodes or other areas of the body (T4a, N0, M0, any G).

Stage IIIB: Cancer is in the outside layer of the esophagus and in three to six lymph nodes (T3, N2, M0, any G).

Stage IIIC: Any of these three conditions:

Cancer has spread beyond the esophagus into nearby tissue. Cancer is also in six or less lymph nodes (T4a, N1 or N2, M0, any G).

Cancer has spread beyond the esophagus into nearby tissue and cannot be removed by surgery (T4b, any N, M0, any G).

Cancer has spread to seven or more lymph nodes but not to distant parts of the body (any T, N3, M0, any G).

Stage IV: Cancer has spread to another part of the body (any T, any N, M1, any G).

Staging of adenocarcinoma of the esophagus

For adenocarcinoma, doctors use the T, N, and M classifications, as well as the grade (G).

Stage 0: This is the same as Tis cancer, in which cancer is found in only the top lining of the esophagus (Tis, N0, M0, G1).

Stage IA: This is the same as T1 cancer, in which the cancer is located in either of the two inside layers of the esophagus only (T1, N0, M0, G1 or G2).

Stage IB: Either of these two conditions:

The cancer is located in either of the two inside layers of the esophagus only, and the tumor cells are poorly differentiated (T1, N0, M0, G3).

The cancer has spread to an outer layer of the esophagus but not to the lymph nodes or other parts of the body (T2, N0, M0, G1 or G2).

Stage IIA: Cancer is in an outer layer of the esophagus, and the cells are poorly differentiated (T2, N0, M0, G3).

Stage IIB: Either of these two conditions:

Cancer is in the outside layer of the esophagus but not beyond (T3, N0, M0, any G).

Cancer is in an inner layer or the muscularis propria of the esophagus and has spread to one or two lymph nodes (T1 or T2, N1, M0, any G).

Stage IIIA: Any of these three conditions:

Cancer is in the inner layers of the esophagus and has spread to three to six lymph nodes near the tumor (T1 or T2, N2, M0, any G).

Cancer is in the outside layer of the esophagus and has spread to one or two lymph nodes (T3, N1, M0, any G).

Cancer has spread beyond the esophagus to nearby tissue but not to lymph nodes or other areas of the body (T4a, N0, M0, any G).

Stage IIIB: Cancer is in the outside layer of the esophagus and in three to six lymph nodes (T3, N2, M0, any G).

Stage IIIC: Any of these three conditions:

Cancer has spread beyond the esophagus into nearby tissue. Cancer is also in six or less lymph nodes (T4a, N1 or N2, M0, any G).

Cancer has spread beyond the esophagus into nearby tissue and cannot be removed by surgery (T4b, any N, M0, any G).

Cancer has spread to seven or more lymph nodes but not to distant parts of the body (any T, N3, M0, any G).

Stage IV: Cancer has spread to another part of the body (any T, any N, M1, any G).

Recurrent: Recurrent cancer is cancer that comes back after treatment. It may come back in the esophagus or in another part of the body. If there is a recurrence, the cancer may need to be staged again (re-staging) using the system above.

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, Seventh Edition (2010) published by Springer-Verlag New York, www.cancerstaging.net.

Thought this might help any newly diagnosed.