Stages of melanoma 02

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1 Useful information for cancer patients Contents This information is about staging for melanoma skin cancer. There are sections on What staging is Types of melanoma staging systems Melanoma thickness (Breslow and Clark scales) TNM staging of melanoma Number stages of melanoma You can view this information in a larger print on our website. What staging is The stage of a melanoma describes how deeply it has grown into the skin, and whether it has spread. The tests you have to diagnose your melanoma will give some information about the stage. In the UK, most melanomas are found at an early stage when the chance of cure is very high. It is important to know the stage because doctors use this to decide on: The kind of treatment you need The likely risk of the melanoma coming back after treatment Whether you need tests to see if the melanoma has spread into lymph nodes close to the melanoma. Types of melanoma staging systems Doctors use a number of different systems and scales to describe the stages of melanoma: The Clark scale looks at how deeply the melanoma has gone into the different layers of the skin The Breslow scale looks at the thickness of the melanoma within the skin TNM staging of melanoma describes the thickness of the melanoma and whether there is any spread to lymph nodes or other parts of the body Number stages of melanoma group together the TNM staging in a simpler way and also according to the treatment needed Doctors in the UK tend to mostly use TNM staging because it describes the stage of melanoma in the most specific way. For treatment decisions and when talking about stage to patients, doctors tend to use the simpler system of number stages. Melanoma thickness (Breslow and Clark scales) There are 2 scales that look at how deeply the melanoma has gone into the skin. These are called the Clark scale and the Breslow scale. When doctors remove a melanoma they send it to a laboratory. A pathologist (an expert who examines and identifies cells) then examines the melanoma and looks at how deeply it has gone into the skin. These days, it is more common for doctors to use the Breslow scale than the Clark scale, when they are staging melanoma. 01

2 The Clark scale You might hear your doctor talk about Clark levels. This is a way of measuring how deeply the melanoma has grown into the skin and which levels of the skin are affected. You can see the main layers of the skin in this diagram. The Breslow scale For the Breslow scale, a pathologist measures the thickness of the melanoma with a small ruler, called a micrometer. Doctors use a scale called the primary tumour thickness scale, or the Breslow thickness. It measures in millimetres (mm) how far the melanoma cells have reached down through the skin from the surface. You can see the structure of the skin in the diagram above. The Breslow thickness is used in the TNM staging system for melanoma. TNM staging of melanoma TNM stands for Tumour, Node, and Metastases. This staging system describes the size of a primary tumour (T), whether any lymph nodes contain cancer cells (N) and whether the cancer has spread to another part of the body (M). The T part of the TNM describes the thickness of the melanoma (primary tumour) according to the Breslow scale. Here are what the different levels of the Clark scale mean: Level 1 is also called melanoma in situ the melanoma cells are only in the outer layer of the skin (the epidermis) Level 2 means there are melanoma cells in the layer directly under the epidermis (the papillary dermis) Level 3 means the melanoma cells are throughout the papillary dermis and touching on the next layer down (the reticular dermis) Level 4 means the melanoma has spread into the reticular or deep dermis Level 5 means the melanoma has grown into the layer of fat under the skin (subcutaneous fat) There are 5 stages of tumour size in melanoma: Tis - melanoma cells are only in the very top layer of the skin surface T1 - the melanoma is less than 1 milllimetre thick T2 - the melanoma is between 1 mm and 2 mm thick T3 - the melanoma is between 2 mm and 4 mm thick T4 - the melanoma is over 4 mm thick It is important not to confuse Clark levels with the TNM stage or number stage. The Clark levels only look at the depth of melanoma cells in the skin. The number stage is looking at whether the melanoma has spread to lymph nodes or another part of the body. 02

3 The T part of the TNM system is further divided into two groups, a and b, depending on whether the melanoma is ulcerated or not. Ulcerated means that the covering layer of skin over the tumour is broken. The letter a means not ulcerated and b means ulcerated. So, for example, a melanoma may be T3a or T3b. Ulcerated melanomas have a higher risk of spreading than those which are not ulcerated. There are 4 possible stages describing whether cancer cells are in the nearby lymph nodes or lymphatic ducts: N0 - there are no melanoma cells in the nearby lymph nodes N1 - there are melanoma cells in one lymph node N2 - there are melanoma cells in 2 or 3 lymph nodes N3 - there are melanoma cells in 4 or more lymph nodes The N part of the stage is further divided into groups a, b and c. If the cancer in the lymph node can only be seen with a microscope (micrometastasis) it is classed as a. But if there are obvious signs of cancer in the lymph node (macrometastasis) it is classed as b. M1 is further divided into: M1a - melanoma cells have spread to skin in other parts of the body or to lymph nodes far away from the where the melanoma started growing M1b- melanoma cells have spread to the lung M1c - melanoma cells have spread to other organs or cause high blood levels of a chemical produced by the liver (lactate dehydrogenase) Nearly everyone in the UK with a newly diagnosed melanoma will only have a T stage. This means that the melanoma has not spread to any lymph nodes or any other part of the body. In a very small number of people, after a melanoma has been removed, nodules of melanoma may appear in the skin close to the area of the original melanoma. This is called local recurrence. It occurs when some melanoma cells have broken away from the primary tumour and begun to grow new tumours (nodules) in the surrounding skin. This can happen at any time after the original melanoma has been removed. So it could be some years later. The more time that has gone by since your original diagnosis, the less likely this is to happen. The letter c means that there are melanoma cells in small areas of skin very close to the primary melanoma or in the skin lymph channels. These groups of melanoma cells in the skin are called satellite metastases. Melanoma cells in the lymph channels are called in transit metastases. M0 means the cancer has not spread to another part of the body. M1 means the cancer has spread to another part of the body. 03

4 Number stages of melanoma There are 5 main stages in this system. They are: Stage 0 (in situ melanoma) This means the melanoma cells are only in the top surface layer of skin cells (the epidermis) and have not started to spread into deeper layers. Stage 1A The melanoma is less than 1mm thick. The covering layer of skin over the tumour is not broken it is not Stage 1B The melanoma is less than 1mm thick and the skin is broken (ulcerated). Or it is between 1 and 2mm and is not ulcerated. The melanoma is only in the skin and there is no sign that it has spread to lymph nodes or other In the UK, most melanomas are stage 1 and are cured with surgery. Stage 2A The melanoma is between 1 and 2 mm thick and is ulcerated. Or it is between 2 and 4mm and is not Stage 2B The melanoma is between 2 and 4mm thick and is ulcerated. Or it is thicker than 4mm and is not Stage 2C The melanoma is thicker than 4mm and is ulcerated. The melanoma is only in the skin and there is no sign that it has spread to lymph nodes or other parts of the body. Stage 3A The melanoma has spread into up to 3 lymph nodes near the primary tumour. But the nodes are not enlarged and the cells can only be seen under a microscope. The melanoma is not ulcerated and has not spread to other areas of the body. Stage 3B Stage 3B means that The melanoma is ulcerated and has spread to between 1 and 3 lymph nodes nearby but the nodes are not enlarged and the cells can only be seen under a microscope OR The melanoma is not ulcerated and it has spread to between 1 and 3 lymph nodes nearby and the lymph nodes are enlarged OR The melanoma is not ulcerated, has spread to small areas of skin or lymphatic channels, but nearby lymph nodes do not contain melanoma cells Stage 3C Stage 3C means that There are melanoma cells in the lymph nodes and small areas of melanoma cells in the skin or lymph channels close to the main melanoma OR The melanoma is ulcerated and has spread to between 1 and 3 lymph nodes nearby which are enlarged OR The melanoma may or may not be ulcerated and has spread to 4 or more nearby lymph nodes OR The melanoma may or may not be ulcerated and has spread to lymph nodes that have joined together Stage 4 These melanomas have spread elsewhere in the body, away from where they started (the primary site) and the nearby lymph nodes. The most common places for melanoma to spread are the lung, liver or brain or to distant lymph nodes or areas of the skin. Most stage 2 tumours can be cured with surgery. 04

5 Notes For more information, visit our website You will find a wide range of detailed, up to date information for people affected by cancer, including a clinical trials database that you can search for trials in the UK. Our information is based on the best current scientific evidence and reviewed regularly by leading clinicians and experts in health and social care. For answers to your questions about cancer call our Cancer Information Nurses on am till 5pm Monday to Friday. Adapted from Cancer Research UK s website in February Cancer Research UK s website is not designed to provide medical advice or professional services and is intended to be for educational use only. The information provided through Cancer Research UK s website and our nurse team is not a substitute for professional care and should not be used for diagnosing or treating a health problem or disease. If you have, or suspect you may have, a health problem you should consult your doctor. Copyright Cancer Research UK Cancer Research UK is a registered charity in England and Wales ( ), Scotland (SC041666) and in the Isle of Man (1103) 05