Your tests and scans give doctors information about the size of the cancer and whether it has spread to another part of your body. This is the stage of your cancer. Knowing this helps your doctors decide what treatment you need.
Doctors can use the TNM system to stage your cancer. TNM stands for Tumour, Node, Metastasis.
Doctors might also use the number staging system.
Tumour describes the size of the cancer. There are 5 T stages for anal cancer.
Tis or carcinoma in situ
Tis is also called AIN, or anal intraepithelial neoplasia. Some of the cells within the lining of the anus have abnormal changes.
T1 means the tumour is 2cm or less.
T2 means the tumour is larger than 2cm but smaller than 5cm.
T3 means the tumour is larger than 5cm.
T4 means the cancer is any size but it is growing into the surrounding organs, such as the bladder, urethra (the tube that carries urine from the bladder out of your body) or the vagina.
Node (N) describes whether the cancer has spread to the nearby lymph nodes, such as lymph nodes near the rectum, in the pelvis or 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) describes whether the cancer has spread to a different part of the body.
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, such as the liver or lungs
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 may include:
- chemoradiotherapy – a combination of chemotherapy and radiotherapy
You may also have treatment as part of a clinical trial.