Stages of anal cancer

Staging describes or classifies a cancer based on how much cancer there is in the body and where it is when first diagnosed. This is often called the extent of cancer. Information from tests is used to find out the size of the tumour, which parts of the organ have cancer, whether the cancer has spread from where it first started and where the cancer has spread. Your healthcare team uses the stage to plan treatment and estimate the outcome (your prognosis).

The staging system for anal cancer applies only to carcinomas (squamous cell or adenocarcinoma). For carcinomas of the perianal skin, only tumours within 5 cm from the anus are staged with the following system.

The most common staging system for anal cancer is the TNM system. For anal cancer there are 5 stages – stage 0 followed by stages 1 to 4. Often the stages 1 to 4 are written as the Roman numerals I, II, III and IV. Generally, the higher the stage number, the more the cancer has spread. Talk to your doctor if you have questions about staging.

When describing the stage of anal cancer, your healthcare team may use the words regional, locally advanced or metastatic.

Regional means that cancer is only in the area around the anus (anal canal or perianal skin) and has not spread to other parts of the body. This includes stages 1 and 2 anal cancer.

Locally advanced means that cancer has spread to the nearby lymph nodes or has grown into nearby organs. This includes stage 3A, 3B and 3C anal cancer.

Metastatic (distant) means cancer has spread to other parts of the body, such as the liver or bone. This is stage 4 anal cancer.

Find out more about staging cancer.

The tumour or abnormal cells are only in the top layer of anal tissue. Stage 0 includes high-grade squamous intraepithelial lesions (HSILs).

The tumour is no more than 2 cm in size.

The tumour is larger than 2 cm but not more than 5 cm.

The tumour is no more than 5 cm across and it has spread to the lymph nodes near the rectum.

The tumour is 5 cm or smaller. The cancer has also spread to nearby lymph nodes, including lymph nodes in the groin, around the rectum or in the pelvis.

The tumour has grown into nearby organs such as the bladder, urethra or vagina.

The tumour is larger than 5 cm or has grown into nearby organs, such as the bladder, urethra or vagina. The cancer has also spread to nearby lymph nodes, including lymph nodes in the groin, around the rectum or in the pelvis.

The cancer has spread to other parts of the body (called distant metastasis), such as to the liver, lungs or bone. This is also called metastatic anal cancer.

Recurrent anal cancer means that the cancer has come back after it has been treated. If it comes back in the same place that the cancer first started, it's called local recurrence. If it comes back in tissues or lymph nodes close to where it first started, it's called regional recurrence. It can also recur in another part of the body. This is called distant metastasis or distant recurrence.