Find out about tumour, node and metastasis (TNM) staging for ethmoid sinus cancer.
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 of ethmoid sinus cancer.
T1 means the tumour is only in the ethmoid sinus, but it may have grown into the bones of the sinus.
T2 means the tumour has begun to grow into other paranasal sinuses or into the nasal cavity and may have started to grow into bone.
T3 means the tumour has spread into the bone of the eye socket, roof of the mouth or maxillary sinus.
T4 means the tumour has spread into other nearby structures such as the eye, skull, brain, sphenoid or frontal sinuses or the skin of the nose or cheek, or the area connecting the back of the nose to the back of the mouth (nasopharynx).
There are 4 main lymph node stages in cancer of the ethmoid sinuses, although N2 is divided into 3 parts - 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, but 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
- 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 ethmoid sinus cancer 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 ethmoid sinus, you have a tumour that has begun to grow into other paranasal 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 ethmoid sinus cancer:
- grade 1 (low grade) - the cancer cells look very much like the normal ethmoid sinus cells
- grade 2 (intermediate grade) - the cancer cells look slightly like normal ethmoid sinus cells
- grade 3 (high grade) - the cancer cells look very abnormal and very unlike normal ethmoid 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 when deciding which treatment is best for you.