TNM staging for salivary gland cancer

The stage of a cancer tells you how big it is and whether it has spread. This is important, as the stage helps your doctor decide which treatment you need.

Your scans and tests will give some information about the stage of your cancer. But your doctor might not be able to tell you the exact stage until after you have surgery.

Types

The staging systems described here are for cancers of the major salivary glands.

We have 3 main pairs of major salivary glands, the:

• parotid glands – just under the lobes of your ears
• sublingual glands – under your tongue
• submandibular glands – under each side of your jawbone

As well as the 3 major pairs of salivary glands we have over 600 smaller, minor salivary glands throughout the lining of the mouth and throat. Minor salivary gland cancers are staged differently, depending on where they start.

TNM stages

TNM stands for Tumour, Node, Metastasis. The system describes:

• the size of a primary tumour (T)
• whether the cancer has spread to the lymph nodes (N)
• whether the cancer has spread to a different part of the body (M)

T (tumour)

T describes the size of the cancer. 

TX means the main cancer (primary) can’t be assessed. It doesn't show on scans but there might be cancer cells present

T1 means the tumour is within the tissue of the salivary gland and is smaller than 2cm in any direction

T2 means the tumour is larger than 2cm, but smaller than 4cm across in any direction

T3 means the tumour is bigger than 4cm. Or the tumour could be any size and it has spread into the soft tissues around the salivary gland.

T4a means the tumour has grown outside the salivary gland into nearby tissues such as the jawbone, ear canal, facial nerves or skin

T4b means the tumour has grown into the bottom of the skull, or the side of the skull, or covers the main blood vessel called the carotid artery

N (node)

This tells you whether the cancer has spread to the lymph nodes.

NX means that the lymph nodes can’t be assessed

N0 means there are no cancer cells in the lymph nodes

N1 means there are cancer cells in one lymph node on the same side as the affected salivary gland and the lymph node is smaller than 3cm in size

N2 is divided into 3 sub groups:

N2a means there are cancer cells in one node on the same side as the affected salivary gland and the lymph node is between 3 and 6cm in size (between 1.2 and 2.4 inches)

N2b means there are cancer cells in several lymph nodes on the same side as the affected salivary gland and the lymph nodes are all smaller than 6cm in size

N2c means there are cancer cells in the lymph nodes on the other side of the face or in lymph nodes on both sides and the lymph nodes are all smaller than 6cm

N3 is divided into 2 sub groups:

N3a means there are cancer cells in at least one lymph node which is bigger than 6cm in size

N3b means that cancer cells have broken through the outside covering of the lymph node

M (metastasis)

This tells you whether the cancer has spread to a different part of the body.

M0 means there is no sign of cancer spread

M1 means the cancer has spread to other parts of the body further away, such as the lungs, liver or bone

Treatment decisions

The stage of your cancer helps your doctor to decide which treatment you need. Your treatment also depends on:

• the type of cancer (the type of cells the cancer started in)
• which salivary gland the cancer started in
• other health conditions that you have