Staging and grading 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).

Our cancer support specialists can tell you more about TNM staging. You can call them on 0808 808 00 00. It is also important to talk to your doctor for detailed information about your situation.

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.