Melanoma Staging - The Key Facts
If you are talking to your oncologist about your melanoma staging prognosis, they may describe it to you in terms that you do not understand. The best advice I can offer is for you to write down every minute detail that you are told, so that when you are in a more calm state of mind you can research it and gather as much information as you can.
Melanoma staging is a complex subject that uses three factors to determine the its result. Some institutions or countries use a single method whereas others may use a combination to ascertain the facts.
The three methods are -
- Breslows Depth
- T.N.M (or T-Stage)
- Numbering System
We found at Addenbrooks Hospital in Cambridge, my mother was told her prognosis using the TNM method and Breslows.
Breslows Scale used to be the most favoured methodology as its simplistic terms gave a clear and consise summary as to the thickness of the skin lesion. After the tumor had been surgically removed, the laboratory would measure it in millimeters with a very precise instrument called a micrometer. As melanomas eventually invade deeper into the skin, Breslows Scale can determine the possibility of whether malignant cells have spread to the lymph nodes yet by how thick the tumor is.
The chart for Breslow's Scale for melanoma staging is as follows (remember, these facts are generalised and do not reflect your own personal circumstances) -
|Breslow's Thickness||Approximate 5 Year Survival|
|1 - 2mm||80-96%|
|2.1mm - 4mm||60-75%|
(The 'Approximate 5 Year survival' is simply a term used by the medical profession as a target, or milestone for all cancers. It is genereally viewed that if a cancer of any kind is going to return, it would probably do so within the first 5 years.)
In laymans terms, if your melanoma was removed and it was found that the depth was less than 1mm, you would have an excellent prognosis. For my mother, her main melanoma on her forearm was removed at 2.2mm. This would estimate that she had an approximate 75% survival rate by 5 years.
The mole on her leg was removed a few weeks later and that was described by her oncologist as 'melanoma in situ' which hopefully will cause her no further problems.
That was nearly 5 years ago and thankfully there has been no recurrence. For us, Breslows Scale was quite accurate.
TNM Melanoma Staging
The TNM methodolgy is far more complicated as it takes many additional factors into consideration. TNM stands for...
- T = Tumour
- N = NODES
- M = Metastases.
T = Tumor
- Stands for how thick the tumor is and is based on Breslows Depth described above. This is further divided into two subcategories depending on whether the tumor has ulcerated or not. If it has ulcerated, it will have a slightly higher risk of spreading.The T code in your medical notes may read something like this - T1a, indicating it was a breslows thickness of less than 1mm and was without uceration. My mothers would have been T2a as it was a 2mm tumor that agian, had not ulcerated. A more serious tumor would look like this - T4b, where it is over 4mm thick and has ulcerated.
N = Nodes
- Stands for lymph NODES and whether cancer cells have spread to them. The coding is similar to above. N0 (zero) states that no lymph nodes have been affected. N1 describes 1 single node is detected. This is further categorised into a and b to describe the type of metastasis, if it is micrometastasis (seen under a microscope) or macrometastasis (can be manually felt during an examination). Your code therefore could look like this - N1b; 1 lymph node has been detected that could be felt during the exam. If it were N1a, cells would have only been visible under a microscope.
M = Metastasise
- Describes where cancer cells may have spread to. Again, the same coding apples. M0 shows there are no cancer cells in other parts of the body. M1b would show that it had spread to the lung for example.
The Numbering System
The third method of melanoma staging is the basic numbering system. This takes the TNM system above and groups it according to four different stages. I think this is the method that most people are familiar with when discussing general cancer stages.
Stage 0 Melanoma
Referred to as melanoma insitu, the cancerous cells are limited to the skin lesion itself in the very top layer of the epidermis. They have not penetrated deeper into the skin and therefore, it has the best possible prognosis once the tumor is removed.
Stage 1 MelanomaStage 1A
Progressing from stage 0 melanoma above, this tumor has a thickness of under 1mm and is not ulcerated (an ulcerated tumor is a slightly higher risk as cells have the ability to spread faster due to the broken skin). There is no evidence that the cancer has spread to the lymph nodes or distant organs.
Two options here, the tumor is still under 1mm in thickness but it has ulceration to it. Alternatively it can be between 1mm and 2mm without ulceration. Again, there is no evidence that lymph nodes are involved and therefore no spread to distant organs.
Stage 2 MelanomaStage 2A
The tumor can be between 1mm and 2 mm thick and has ulceration to it. Alternatively it can be between 2mm and 4mm thick but with no ulceration. Again, no lymph node involvement and no spread to distant organs.
The tumor can be between 2mm and 4mm thick and has ulceration to it. No lymph node involvement and no spread to distant organs.
The tumor has a thickness greater than 4mm and has ulceration to it. No lymph node involvement and no spread to distant organs.
Stage 3 Melanoma
A slightly more advanced melanoma having involved up to 3 lymph nodes nearest the primary melanoma site. These are micrometastases and can only be seen under a microscope and not felt manually during an examination. There is no ulceration of the tumor and no further spread to distant organs at this stage.
Stage 3B has three alternatives -
- The tumor involves up to 3 local lymph nodes but is only micrometastases and can only be seen microscopically. Ulceration is present but there is no spread to distant organs.
- The tumor involves up to 3 local lymph nodes and are enlarged meaning they can be felt during an examination. There is no ulceration of the tumor ad it has not spread to distant organs.
- The tumor has small satellite lesions nearby and the primary melanoma may, or may not be ulcerated. There are no cancerous cells present in the lymph nodes and it has not spread to distant organs.
This stage has three alternatives -
- The tumor is ulcerated and involves up to 3 local lymph nodes and are enlarged meaning they can be felt during an examination. There are cancer cells present but they have not spread to distant organs.
- The tumor may or may not be ulcerated and involves to more than 4 local lymph nodes which are enlarged and can be felt during an examination. There are cancer cells present but they have not spread to distant organs.
- The tumor has small satellite lesions nearby and the primary melanoma may, or may not be ulcerated. Cancer cells can be found in any lymph nodes.
Stage 4 Melanoma
- The tumor has spread further than the local lymph nodes and is in distant organs.
Melanoma staging is a complex process that as you can see, involves many tests, theories and investigation. It is fair to say that we are lucky in that most poeple are diagnosed at an early stage such as stage 1 or stage 2 where effective treatments and research means that life expectancy is far better.
People diagnosed with later stage melanomas can still survive years if managed and treated correctly. Survival rates can also be determined by general factors such as the age of the patient, their overall health and wellbeing, their ability to manage stress and their positive outlook. It is so important to remember that melanoma does not mean a death sentence today, my mother is living proof of that.
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