Staging

Staging is a way of describing a 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 all the tests are finished. 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 amount of cancer found in the gallbladder. Some stages are also divided into smaller groups that help describe the tumor in even more detail. This helps the doctor develop the best treatment plan for each patient. Specific tumor stage information is listed below.

TX: The primary tumor cannot be evaluated.

T0: No evidence of cancer was found in the gallbladder.

Tis: This classification is used when there is a condition called carcinoma (cancer) in situ. This means that the tumor remains in a pre-invasive state and its spread, if any, is very confined.

T1: The tumor is in the gallbladder only and has only invaded the lamina propria (a type of connective tissue found under the thin layer of tissue covering a mucous membrane) or muscle layer.

T1a: The tumor has invaded the lamina propria.

T1b: The tumor has invaded the muscle layer.

T2: The tumor has invaded the perimuscular connective tissue (the layer between the muscle layer and the serosa) but has not extended beyond the serosa (the outer layer) or into the liver.

T3: The tumor extends beyond the gallbladder and/or has invaded the liver and/or one other adjacent organ or structure, such as the stomach, duodenum, colon, or pancreas.

T4: The tumor has invaded the main portal vein or hepatic artery or has invaded more than one organ or structure beyond the liver.

Node. The “N” in the TNM staging system stands for lymph nodes, the tiny, bean-shaped organs that help fight infection. Lymph nodes near the gallbladder are called regional lymph nodes.

NX: The regional lymph nodes cannot be evaluated.

N0 (N plus zero): There is no regional lymph node metastasis.

N1: There is regional lymph node metastasis.

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

MX: Distant metastasis cannot be evaluated.

M0 (M plus zero): There is no distant metastasis.

M1: There is metastasis to one or more other parts of the body.

Cancer stage grouping

Doctors assign the stage of the cancer by combining the T, N, and M classifications.

Stage 0: Describes cancer in situ (Tis, N0, M0).

Stage IA: A tumor is in the gallbladder only and has not spread (T1, N0, M0).

Stage IB: A tumor has extended to the perimuscular connective tissue but has not spread elsewhere (T2, N0, M0).

Stage IIA: A tumor has spread beyond the gallbladder but not to nearby arteries or veins. It has not spread to any lymph nodes or other parts of the body (T3, N0, M0).

Stage IIB: The tumor of any size has spread to the lymph nodes, but not to nearby arteries and/or veins or to other parts of the body (T1, T2, T3; N1; M0).

Stage III: The tumor has spread to nearby arteries, veins, and/or lymph nodes, but it has not spread to other parts of the body (T4, any N, M0).

Stage IV: Describes any tumor that has spread to other parts of the body (any T, any N, M1).

Recurrent: Recurrent gallbladder 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