The stage of a cancer describes its size and if it has spread from where it started. Knowing the stage helps the doctors decide on the best treatment for you.
Generally, anal cancer is divided into four stages. Cancers that are small and only in the anus are called localised cancer. Cancer that has spread to other parts of the body is called secondary or metastatic cancer.
If a cancer comes back after it is first treated, it is called a recurrent cancer.
The staging systems most commonly used for anal cancer are:
- TNM staging
- the number staging system.
This information is about squamous cell anal cancers. We have separate information about other types of anal cancer.
The TNM system is more complicated. It gives precise information about the tumour stage.
- T – describes the size of the tumour and whether it has grown into nearby tissues or organs.
- N – describes whether the cancer has spread to the lymph nodes.
- M – describes whether the cancer has spread to another part of the body, such as the liver.
T – Tumour
Doctors put a number next to the T to describe the size and spread of the cancer.
- Tis – The cancer is at its earliest stage. There are cancerous changes to some of the cells, but they are only in the lining of the anus (in situ). If left untreated, these cells may spread into the tissues outside the lining and become an invasive cancer.
- T1 – The tumour is 2cm or smaller.
- T2 – The tumour is more than 2cm up to 5cm.
- T3 – The tumour is bigger than 5cm.
- T4 – The tumour can be any size, but it has started to grow into nearby structures, such as the vagina, bladder or urethra (the tube that carries urine from the bladder).
N – Nodes
This describes whether any lymph nodes near the anus contain cancer cells.
- NX – The lymph nodes were not examined.
- N0 – There is no cancer in the lymph nodes.
- N1 – There is cancer in the lymph nodes closest to the anus. The lymph nodes closest to the anus are in the rectum.
Stage N1 can be broken down into 3 further stages called N1a, b or c. These stages depend on which lymph nodes in the groin and pelvis have cancer cells in them.
M – Metastasis
Metastasis means that the cancer has spread to other parts of the body.
- M0 – The cancer has not spread to other parts of the body.
- M1 – The cancer has spread to other parts of the body, such as the liver or the lymph nodes in the tummy (abdomen).
Another staging system commonly used for anal cancer is Number staging.
The cancer only affects the anus. It is smaller than 2cm.
The cancer is 2 to 5cm and has not spread to any lymph nodes.
The cancer is 5cm or more and has not spread to any lymph nodes.
This is divided into three stages:
This stage means the cancer is either:
- 2cm or smaller and has spread to the lymph nodes near the rectum and in the groin or pelvis, or
- the cancer is 2-5cm and has spread to the lymph nodes near the rectum and in the groin or pelvis.
The cancer is any size and has spread to nearby organs such as the bladder, urethra or vagina.
The cancer is any size and has spread to lymph nodes in the groin and pelvis.
The cancer has spread to other parts of the body, such as the liver.
The grade describes how cancer cells look and behave compared to normal cells. Doctors will look at a sample of the cancer cells under a microscope to find the grade of your cancer.
Grade 1 (low-grade)
The cancer cells tend to grow slowly and look similar to normal cells (they are well differentiated). These cancers are less likely to spread than higher-grade cancers.
Grade 2 (moderate-grade)
The cancer cells look more abnormal.
Grade 3 (high-grade)
The cancer cells tend to grow more quickly and look very abnormal (they are poorly differentiated). These cancers are more likely to spread than low-grade cancers.
Below is a sample of the sources used in our anal cancer information. If you would like more information about the sources we use, please contact us at firstname.lastname@example.org
R Glynne-Jones, PJ Nilson, C Aschele et al. ESMO-ESSO-ESTRO clinical practice guidelines for diagnosis, treatment and follow up for anal cancer. July 2014. European Society of Medical Oncology. Available from www.esmo.org/Guidelines/Gastrointestinal-Cancers/Anal-Cancer (accessed October 2019).
Association of Coloproctology of Great Britain & Ireland (ACPGBI). Volume 19. Issue S1. Guidelines for the management of cancer of the colon, rectum and anus. 2017. Available from: www.onlinelibrary.wiley.com/toc/14631318/19/S1 (accessed October 2019).
R Muirhead, RA Adams, DC Gilbert et al. National guidance for IMRT in anal cancer. December 2016 (accessed October 2019).
D Ryan, C Willett et al. Clinical features, staging, and treatment of anal cancer. Uptodate 2019. Available at www.uptodate.com/contents/clinical-features-staging-and-treatment-of-anal-cancer (accessed October 2019).
This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Chief Medical Editor, Professor Tim Iveson, Consultant Medical Oncologist.
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