Find out about tumour, node and metastasis (TNM) staging for maxillary sinus cancer.
What TNM staging means
TNM stands for tumour, node and metastasis. The system describes:
- the size of a primary tumour (T) and how far it’s grown locally
- whether the cancer has spread to the lymph nodes (N)
- whether the cancer has spread in the bloodstream to a different part of the body (M)
There are 4 main T stages for maxillary sinus cancer.
T1 means the tumour is only in the innermost most tissues lining the sinus. It has not grown into the bone.
T2 means the tumour has begun to grow into the bone surrounding the maxillary sinus. (If the tumour is in the bone in the back part of the sinus - the posterior wall - it is T3.)
T3 means the tumour has begun to grow into the back (posterior) wall or into bones of any of the other sinuses. If the cancer grows right through these bones it may reach the tissues under the skin, the skin of the cheek, the eye socket or the ethmoid sinus in front of the maxillary sinus.
T4 means the tumour has grown into any other nearby structures such as the eye, skull, skin of the cheek, the tissues below the temple, the area connecting the back of the nose to the back of the mouth (nasopharynx), sphenoid or frontal sinuses or up into the brain.
There are actually 2 parts to T4. These are T4a and T4b. But the definitions of these are so complicated and technical that we haven’t gone into them here.
There are 4 main lymph node stages in maxillary sinus cancer, although N2 is divided into 3 parts. These are 2a, 2b and 2c. The important points here are whether there is cancer in any of the lymph nodes, and if so, how big they are and where they are.
- N0 means there are no lymph nodes containing cancer cells
- N1 means there are cancer cells in one lymph node on the same side of the neck as the tumour and the node measures 3cm across or less
- N2a means there is cancer in one lymph node, on the same side of the neck, that is more than 3cm across but no more than 6cm across
- N2b means there is cancer in more than one lymph node on the same side of the neck, but none of them are more than 6cm across
- N2c means there is cancer in lymph nodes on the other side of the neck (or on both sides) but none are more than 6cm across
- N3 means that one or more nodes contain cancer and at least one node is more than 6cm across
There are 2 stages to describe spread of cancer of the maxillary sinuses to other parts of the body:
- 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, brain or liver
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 of the maxillary sinuses, you have a tumour that has begun to grow into other sinuses. The lymph nodes are clear and there is no spread of your cancer to other parts of the body.
The grade of a cancer tells you how much the cancer cells look like normal cells. There are 3 grades of maxillary sinus cancer:
- grade 1 (low grade) - the cancer cells look very much like the normal maxillary sinus cells
- grade 2 (intermediate grade) - the cancer cells look slightly like normal maxillary sinus cells
- grade 3 (high grade) - the cancer cells look very abnormal and very little like normal maxillary sinus cells
The word differentiation means how developed or mature a cell is. So you may hear your doctor describe grade 1 cancer cells as well differentiated. Grade 2 cancer cells are moderately differentiated. Grade 3 cancer cells are poorly differentiated.
The grade of the cancer gives your specialist a guide as to how the cancer is likely to behave. Low grade cancers are usually slower growing and less likely to spread.
High grade cancers are likely to be faster growing and are more likely to spread. This is only a guide. Your specialist will consider all your test results, and the stage of the cancer (see above) when deciding which treatment is best for you.