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Grade and stage of mouth cancers

The stage of a cancer tells the doctor how big the cancer is and whether it has spread. The staging information helps your doctor to decide on the best treatment. The two main staging systems are the TNM system and the number system.

TNM stages of mouth and oropharyngeal cancer

TNM stands for Tumour, Node and 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)

Number stages of mouth and oropharyngeal cancers

There are four main stages in this system – stages 1 to 4. Some doctors also refer to stage 0, which is an early stage before a true cancer develops. Stage 1 means a cancer that is 2 across or less and only in the area where it first started. Stage 2 means a cancer larger than 2cm that has not spread. Stage 3 means a cancer larger than 4cm that has not spread or that the cancer has spread into a nearby lymph node. Stage 4 means it has spread deeply into nearby structures or has spread into lymph nodes or it has spread to another part of the body. 

Grade of mouth and oropharyngeal cancers

The grade of a cancer tells you what the cells look like under a microscope. They are graded according to how normal or abnormal they appear. The more abnormal they look, the higher the grade. Mouth and oropharyngeal cancers are graded from 1 (low grade) to 4 (the highest grade).

 

CR PDF Icon You can view and print the quick guides for all the pages in the Treating mouth cancer section.

 

 

What staging is

The stage of a cancer means how big it is and whether it has grown or spread. The staging information helps your doctor to decide on the best treatment. The tests and scans that you had to diagnose your cancer give some staging information. But if you need surgery your doctor may not be able to tell you the exact stage until after the operation.

 

Staging systems for mouth and oropharyngeal cancers

There are different ways of staging cancers. The two main systems are the TNM system and number system.

Understanding your cancer stage may help you understand why your specialist has recommended a particular treatment for you. If you don't understand and would like to know more, you can ask your doctor. There is a list of questions for your doctor at the end of this section that may help you. There is also more information about staging cancers in the about cancer section.

 

TNM stages of mouth and oropharyngeal cancers

TNM stands for Tumour, Node and 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 stages

There are 4 main T stages of mouth and oropharyngeal cancer

  • T1 means the tumour is contained within the tissue of the mouth or oropharynx and is no larger than 2cm (¾ inch)
  • T2 means the tumour is larger than 2cm, but smaller than 4cm (about 1½ inches)
  • T3 means the tumour is bigger than 4cm
  • T4a means the tumour has grown further than the mouth or oropharynx and into nearby body tissues such as bone, tongue, the air cavities of the face (sinuses) or the skin
  • T4b means the tumour has spread into nearby areas such as the space around and behind the jaws, the back of the upper jaw where the large jaw muscles attach, the base of the skull, or the area of the neck that surrounds the main arteries (carotid arteries)

N stages

There are 4 main lymph node stages in cancer of the mouth and oropharynx. One of these, stage N2, is broken down into 3 sub stages. The important points here are whether there is cancer in the lymph nodes in the neck and if so, the size of the node and which side of the neck it is on.

  • N0 means there are no cancer cells in the lymph nodes
  • N1 means there are cancer cells in 1 lymph node on the same side of the neck as the cancer, but the node is less than 3cm across
  • N2a means there is cancer in 1 lymph node on the same side of the neck, and the node is more than 3cm across but less than 6cm across
  • N2b means there is cancer in more than 1 lymph node, but none of these nodes are more than 6cm across. All the affected nodes are on the same side of the neck as the cancer.
  • N2c means there is cancer in nodes on the other side of the neck, or in nodes on both sides, but none of these nodes are more than 6cm across
  • N3 means that at least 1 node containing cancer is more than 6cm across

M stages

There are two M stages for cancers of the mouth and oropharynx

  • M0 means there is no cancer spread to other parts of the body
  • M1 means the cancer has spread to other parts of the body, such as the lungs

Together, the T, N and M stages give a complete description of the stage of your cancer. For example, if you have a T2, N0, M0 cancer, you have a tumour larger than 2cm but not larger than 4cm. There are no cancer cells in the lymph nodes and there is no spread of your cancer to other parts of the body.

 

Number stages of mouth and oropharyngeal cancers

There are four main stages in this system – stages 1 to 4. Some doctors also refer to stage 0.

Stage 0 or carcinoma in situ (CIS)

If you have CIS or stage 0 cancer of the mouth or oropharynx, you have a very early stage cancer. Some doctors prefer to call this pre cancer. There are cancer cells but they are all contained within the lining of the mouth or oropharynx. So they have not spread. As the cells have not spread, this is not yet a true cancer. If the pre cancer is not treated, there is a high chance of this condition going on to develop into an invasive cancer.

Stage 1

This is the earliest stage of invasive cancer. It means that cancer has begun to grow through the tissues lining the mouth or oropharynx and into the deeper tissues underneath. The cancer is no more than 2 cm across and has not spread to nearby tissues, lymph nodes or other organs.

Stage 2

If you have stage 2 cancer, the tumour is larger than 2cm across, but less than 4cm. The cancer has not spread to lymph nodes or any other organs.

Stage 3

Having stage 3 mouth or oropharynx cancer can mean one of two things. Either the cancer is bigger than 4cm but has not spread to any lymph nodes or other parts of the body. Or the tumour is any size but has spread to one lymph node on the same side of the neck as the cancer. In this case the lymph node involved is no more than 3cm across.

Stage 4

Stage 4 means the cancer is advanced. It is divided into 3 stages

  • Stage 4a means the cancer has grown through the tissues around the lips and mouth – lymph nodes in the area may or may not contain cancer cells
  • Stage 4b means the cancer is any size and has spread to more than 1 lymph node on the same side of the neck as the cancer, or to lymph nodes on both sides of the neck, or any lymph node is bigger than 6cm
  • Stage 4c means the cancer has spread to other parts of the body such as the lungs or bones
 

The grades of mouth and oropharyngeal cancer

The grade of a cancer tells you what the cells look like under a microscope. The cells are graded according to how normal or abnormal they appear. There are 4 grades of oral and oropharyngeal cancer cells

  • Grade 1 (low grade) – the cancer cells look very much like normal mouth or oropharyngeal cells
  • Grade 2 (intermediate grade) – the cancer cells look slightly different to normal mouth or oropharyngeal cells
  • Grade 3 (high grade) – the cancer cells look very abnormal and not much like normal mouth or oropharyngeal cells
  • Grade 4 (high grade) – the cancer cells look very different to normal mouth or oropharyngeal cells

Differentiation means how developed or mature (differentiated) a cell is. So doctors may describe grade 1 cancer cells as well differentiated. Grade 2 cancer cells are moderately differentiated. Grade 3 cancer cells are poorly differentiated. Grade 4 cells are undifferentiated.

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Updated: 14 October 2014