TNM staging for anal cancer

The stage of a cancer tells you how big it is and how far it has spread. Knowing this helps your doctor decide the best treatment for you.

TNM stands for Tumour, Node and Metastasis. Doctors use the TNM system to stage cancer. Doctors may also use the number system.

Tumour (T)

Tumour describes the size of the cancer. There are 5 T stages for anal cancer.

Tis 

Tis means some of the cells within the lining of the anus have abnormal changes. Doctors call this anal intraepithelial neoplasia (AIN) 2-3. Or a high-grade squamous intraepithelial lesion (HSIL). You might also hear it called carcinoma in situ. 

This is not cancer but the cells might develop into cancer in the future.

T1

T1 means the cancer is 2cm or smaller.

If the cancer hasn't spread to the nearby lymph nodes or other parts of the body, T1 anal cancer is the same as number stage 1.

T2

T2 means the cancer is larger than 2cm, but no bigger than 5cm.

If the cancer hasn't spread to the nearby lymph nodes or other parts of the body, T2 anal cancer is the same as number stage 2a.

T3

T3 means the cancer is larger than 5cm.

If the cancer hasn't spread to the nearby lymph nodes or other parts of the body, T3 anal cancer is the same as number stage 2b.

T4

T4 means the cancer is any size, but it is growing into the surrounding organs. This might include the bladder , urethra  or the vagina . 

If the cancer hasn't spread to the nearby lymph nodes or other parts of the body, T4 anal cancer is the same as number stage 3b.

Node (N)

Node describes whether the cancer has spread to the lymph nodes near the cancer. These are the lymph nodes near the rectum, in the area between your hips (pelvis) or in your groin.

There are 2 main N stages for anal cancer:

• N0 means there are no cancer cells in the nearby lymph nodes 
• N1 means there are cancer cells in the nearby lymph nodes 

N1 can be further divided into a, b or c, depending on which lymph nodes the cancer cells have spread to.

Metastasis (M)

Metastasis describes whether the cancer has spread elsewhere in the body, such as the liver and lungs.

There are 2 M stages for anal cancer:

• M0 means the cancer hasn't spread to another part of the body
• M1 means the cancer has spread to another part of the body

Where a cancer has spread to is called a secondary cancer. Secondary cancers are also called metastases. Unfortunately, if the cancer has spread elsewhere in the body, it means the cancer is advanced. 

Treatment

The stage of your cancer helps your doctor to decide which treatment you need. Treatment also depends on:

• your type of cancer (the type of cells the cancer started in)
• where the cancer is 
• other health conditions that you have

The stage of the cancer and these other factors can also give an idea of your outlook (prognosis).

Squamous cell cancer is the most common type of anal cancer. Treatment might include:

• chemoradiotherapy – a combination of chemotherapy and radiotherapy
• surgery
• chemotherapy 
• radiotherapy

You may also have treatment as part of a clinical trial.

How you might feel

Anal cancer stages can be difficult to understand. You might feel frightened or overwhelmed after being told you have cancer. So you might not be able to take in everything your doctor tells you.

It might help to have a relative or friend with you when you see your doctor. They can:

• support you
• ask questions
• take notes for you

You might also want to talk with your specialist nurse about the cancer stage. But you may want to wait until you’ve had a chance to take in what your doctor has said. Your specialist nurse can also arrange for you to see your doctor again if necessary.