Stage 3 anal cancer

Anal cancer can start in different cell types. This information is for ​squamous cell cancer​ which is the most common type of anal cancer.

Find out more about anal cancer that starts in other cell types

Staging anal cancer

The stage of a cancer tells the doctor about its size and whether it has spread. It helps your doctor decide on which treatment you need.

There are 4 number stages of anal cancer numbered 1 to 4. Stage 3 anal cancer means the cancer hasn't spread to distant parts of the body. But it can be any size, and it also one of the following:

• growing into nearby organs such as the ​vagina​, ​urethra​ or ​bladder​

• has spread to the nearby ​lymph nodes​

• has both grown into nearby organs and spread to nearby lymph nodes

Stage 3 is divided into 3A, 3B and 3C. 

TNM staging

Doctors also use another staging system for anal cancer. They call this the TNM staging system. It stands for tumour, node and metastasis: 

• T describes the size of the tumour

• N describes whether there are any cancer cells in the nearby lymph nodes

• M describes whether the cancer has spread elsewhere in the body

The TNM system describes the cancer in detail. The number staging system puts these details together to give an overall stage. 

Read more about TNM staging

Stage 3A anal cancer

This means the cancer is no bigger than 5cm. And has spread to nearby lymph nodes in the rectum, pelvis or the groin. But it hasn't spread to other parts of the body.

Number stage 3A is the same as the TNM stages:

• T1, N1, M0  

• T2, N1, M0

Find out more about the lymph nodes and cancer

Stage 3B anal cancer

This means the cancer is any size and is growing into the surrounding organs, such as the:

• bladder

• urethra

• vagina

The cancer hasn't spread to the nearby lymph nodes or any other parts of the body. 

Number stage 3B is the same as T4, N0, M0 in the TNM staging system.

Stage 3C anal cancer

This means the cancer has spread to the nearby lymph nodes but not to other parts of the body.

The cancer can be larger than 5cm, but hasn't grown into the surrounding organs, such as the urethra, vagina or bladder.

This is the same as TNM stage T3, N1, M0.

Stage 3C can also mean a cancer of any size that has grown into organs such as the urethra, vagina or bladder, as well as the nearby lymph nodes.

This is the same as TNM stage T4, N1, M0.

Your doctor will explain how big the cancer is and if it has spread to the surrounding organs.

Treatment for stage 3 anal cancer

Knowing the stage of the cancer helps your doctor decide which treatment is best for you. Treatment can also depend on:

• where the cancer is in your anus

• your general health

Chemoradiotherapy

The main treatment for stage 3 anal cancer is chemoradiotherapy. This means you have both:

• chemotherapy

• radiotherapy

Chemotherapy uses anti cancer drugs to destroy cancer cells. These drugs are also called cytotoxic drugs. They circulate throughout the body in the bloodstream. Radiotherapy uses high energy waves similar to x-rays to kill cancer cells.

When you have finished your treatment, your doctor will check that the cancer has completely gone.

Unfortunately, chemoradiotherapy isn't suitable for everyone. Your doctor will talk to you about other options if they feel it isn't the best treatment for you.

Find out more about chemoradiotherapy for anal cancer

If your doctor thinks there are still cancer cells

If your doctor thinks there is any cancer left after chemoradiotherapy, they take a sample of tissue (biopsy) from the area. If this contains cancer cells, they will talk to you about further treatment. This may include a large operation called an abdominoperineal resection (APR). Your surgeon and ​anaesthetist​ will make sure you are well enough to have this surgery.

Read more about surgery for anal cancer

Other stages of anal cancer

• Stage 0 (anal intraepithelial neoplasia)

• Stage 1

• Stage 2

• Stage 4