Once a diagnosis of anal cancer is made, additional test should be ordered to determine the extent of the disease. A CT (CAT) scan or MRI of the abdomen and pelvis should be performed to look for abnormally enlarged lymph nodes, which can result from spread of the cancer, and to examine the liver for metastatic disease. A chest x-ray is often performed to look for spread of the cancer to the lungs. In some cases, an ultrasound of the tumor using a probe that is inserted into the anus can be used to determine the amount of invasion of the tumor into the surrounding tissues.
Anal cancer is most commonly staged using the TNM staging system which is determined by the American Joint Committee on Cancer. The "T stage" represents the extent of the primary tumor itself. The "N stage" represents the degree of involvement of the lymph nodes. The "M stage" represents whether or not there is spread of the cancer to distant parts of the body. These are scored as follows:
T Stage
Tis: Carcinoma in situ
T0: No evidence of primary tumor
T1: Tumor 2 cm or less in greatest dimension
T2: Tumor is greater than2 cm but less than 5 cm in greatest dimension
T3: Tumor is greater than5 cm in greatest dimension
T4: Tumor of any size that invades adjacent organs including the vagina, urethra, or bladder. Tumors that invade the anal sphincter only do not qualify as T4 tumors
N Stage
N0: No evidence of spread to the lymph node
N1: Spread of cancer to the lymph nodes directly adjacent to the rectum (perirectal lymph nodes)
N2: Spread of the cancer to lymph nodes of the inguinal or internal iliac lymph node chains on one side only.
N3: Spread of the cancer to lymph nodes of the inguinal or internal iliac lymph node chains on both sides OR cancer involvement of both the perirectal lymph nodes and the inguinal lymph nodes
M Stage
M0: No evidence of distant spread of the cancer
M1: Evidence of distant spread of the cancer to other organs, or to lymph node chains other than the ones lists under "N stage"
The stage of the cancer is reported by stating the stage of the T, the N, and the M. For example, a patient with a 4 cm tumor that had spread to perirectal lymph nodes, but did not invade into adjacent organs or spread to any other lymph nodes would be classified as T2N1M0. The staging can be further condensed into a stage group, which takes the various combinations of TNM and places them into groups designated stage 0-IV. While there is a system for stage grouping of anal cancers, these tumors are more commonly referred to by their direct TNM stage.
Although this system of cancer staging is quite complicated, it is designed to help physicians describe the extent of the cancer, and therefore, helps to direct what type of treatment is given.
Anal cancer is most commonly staged using the TNM staging system which is determined by the American Joint Committee on Cancer. The "T stage" represents the extent of the primary tumor itself. The "N stage" represents the degree of involvement of the lymph nodes. The "M stage" represents whether or not there is spread of the cancer to distant parts of the body. These are scored as follows:
T Stage
Tis: Carcinoma in situ
T0: No evidence of primary tumor
T1: Tumor 2 cm or less in greatest dimension
T2: Tumor is greater than2 cm but less than 5 cm in greatest dimension
T3: Tumor is greater than5 cm in greatest dimension
T4: Tumor of any size that invades adjacent organs including the vagina, urethra, or bladder. Tumors that invade the anal sphincter only do not qualify as T4 tumors
N Stage
N0: No evidence of spread to the lymph node
N1: Spread of cancer to the lymph nodes directly adjacent to the rectum (perirectal lymph nodes)
N2: Spread of the cancer to lymph nodes of the inguinal or internal iliac lymph node chains on one side only.
N3: Spread of the cancer to lymph nodes of the inguinal or internal iliac lymph node chains on both sides OR cancer involvement of both the perirectal lymph nodes and the inguinal lymph nodes
M Stage
M0: No evidence of distant spread of the cancer
M1: Evidence of distant spread of the cancer to other organs, or to lymph node chains other than the ones lists under "N stage"
The stage of the cancer is reported by stating the stage of the T, the N, and the M. For example, a patient with a 4 cm tumor that had spread to perirectal lymph nodes, but did not invade into adjacent organs or spread to any other lymph nodes would be classified as T2N1M0. The staging can be further condensed into a stage group, which takes the various combinations of TNM and places them into groups designated stage 0-IV. While there is a system for stage grouping of anal cancers, these tumors are more commonly referred to by their direct TNM stage.
Although this system of cancer staging is quite complicated, it is designed to help physicians describe the extent of the cancer, and therefore, helps to direct what type of treatment is given.
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