Melanoma is a type of skin cancer which affects the melanocytes of the skin, which give skin its color. It is a malignant tumor and may develop from an existing mole or as a new mole. It being malignant means that it is a dangerous condition and can lead to death. The common sites they affect are the legs, back, and anywhere else on the skin. Rarely will they be found on the intestines, eyes, or even on the mouth. The cause of this lethal disease is sensitive exposure to UV rays by various sources, including the sun.
When doctors tell a patient that he or she has melanoma, the next question often asked is the stage. Remember, it is our aim through this article to inform you of the stages of melanoma. Staging is the measurement of the severity of cancer. Doctors often stage cancers from one to four, since most people understand it that way. Determining the stage of melanoma is very important for treatment. In most cases, melanoma at its early stages is highly curable and less likely to recur in the future, whereas a stage IV melanoma with signs of distant metastasis (growth) may be difficult to treat.
There are different staging systems used to classify the tumor and its characteristics. Most used systems are the Numerical Staging from Stage 0 – 4 and the ‘TNM’ system, which is relatively the more preferred one.
Stages of Melanoma Using the Zero-One-Two-Three-Four Approach
Here are the stages of melanoma using the zero-one-two-three-four approach:
The first stage is stage zero. The tumors in this stage have not invaded the surface below the skin (in situ) and look like a small bump on the skin or resemble a mole. This developing melanoma is not invasive at this stage.
This is the second stage. Melanoma is small and very shallow, typically not more than 2 millimeters in thickness. Melanoma at this stage has not yet spread to lymph nodes or other parts of the body.
This is the third stage of melanoma and is characterized by a lesion with at least 2 millimeters in thickness. The lesion may or may not have broken the skin or caused ulcerations. Stage 2 melanomas are still localized and have not yet spread to lymph nodes or other areas of the body.
This is the fourth stage of melanoma. Stage 3 melanomas have evidence of spreading to nearby lymph nodes, but they are not on distant parts of the body. The size and deepness of lesions at this time is not important.
This is the fifth stage. Stage 4 melanoma is characterized by spreading to other areas of the body (metastasis). This is the last stage of melanoma.
The zero-one-two-three-four approach is a good method of staging melanoma, but there is another approach that describes cancer severity more accurately. This approach is known as tumor, node, and metastasis (TNM) staging.
Understanding Melanoma Using TNM Staging Method
Health professionals tend to stick to TNM staging for cancers such as melanoma. It describes the cancer more accurately, so it would be advantageous if you try to understand it. TNM is not complicated or confusing once you understand what it means. The parameters on which this staging system is based upon are the tumor thickness (unit used is Breslow’s thickness), the definite look of the ulceration (skin above the tumor is injured), and the speed at which the cancer is increasing (mitotic rate).
T is for tumor
The ‘T’ stands for the primary tumor or the site where cancer first started to develop. Melanoma lesions worsen by growing deep into the skin. The severity of ‘T’ is measured as follows:
- Tis - means ‘in situ,' which means that melanoma cancer cells are contained on the very top of the skin and have not spread or grown into the deeper layers of the skin. This is the earliest stage of melanoma.
- T1 – This is the first warning stage. With an invasive character, the melanoma is less than 1 millimeter in thickness. It is multiplying at the rate of 1 per mm2 with no signs of ulceration (pus discharge).
- T2 – Melanomas are 1 millimeter to 2 millimeters thick. There is no ulceration seen here.
- T3 – Melanomas are 2 millimeter to 4 millimeters thick. In this stage, there might be an ulceration seen.
- T4 – Melanomas are more than 4 millimeters in thickness with signs of sore discharge seen from the affected area.
The ulceration varies (may or may not be present) from person to person with each progressive stage.
‘N’ means lymph nodes
For most cancers, when they first start to spread, they affect the Lymph Nodes first. ‘N’ stands for Node, which in this case implies the presence of cancer cells in the Lymph Nodes. In this, doctors also make use of a biopsy of the sentinel Lymph Node (lymph nodes likely to be affected).
Lymph Node involvement is denoted as follows:
- N0 – No presence of cancer cells in the Lymph Nodes.
- N1 – There are cancer cells in one Lymph Node.
- N2 – There are cancer cells affecting two or three Lymph Nodes.
- N3 – Melanoma cancer cells have affected at least 4 or more Lymph Nodes.
‘M’ is for metastasis
Metastasis means the spread of cancer cells away from the primary tumor. Melanoma is the only type of skin cancer that readily metastasizes. Metastasis significantly worsens the prognosis of melanoma. The severity of metastasis is described as follows:
- M0 – No evidence of metastasis.
- M1a – metastasis to the skin and distant Lymph Nodes.
- M1b – spread of cancer cells to other sites of the body away from the primary tumor.
- M1c – metastasis or spread of cancer cells to a lung.
The doctor examines the patient’s primary tumor, Lymph Nodes, and checks for the presence of metastasis, and denotes the findings using the TNM staging method to determine the severity of melanoma.
The following is the use of an example of TNM staging for a case of stage 3 melanoma:
This means that the primary tumor is at between 1 to 2 millimeters in thickness, has already spread to one nearby Lymph Node, but has no evidence of metastasis. As you notice, using the TNM staging enables better presentation of Melanoma case than the simple one-two-three-four staging.
The good news is that early stages of melanoma are highly curable, especially if cancer has not yet spread to Lymph Nodes or to other parts of the body. The only necessary action to be taken is getting clinical checkups at regular intervals.
Melanoma is a malignant or rather deadly type of skin cancer whose early diagnosis will help in a big way in its treatment. Just like it is easier to discipline a child and prepare them for a disciplined future than it is for a grown up, if the cancer is left for long, then treating it becomes very hard at advanced stages. For all the methods used in staging melanoma, there are several stages for melanoma. The TNM method is, however, more accurate and more preferred in staging melanoma. Upon realization of the presence of melanoma on one's skin, immediate treatment should be sought. The earlier it is done the better.
Thank you for reading this article.
- Staging melanoma is important for treatment.
- Melanoma is highly curable at early stages.
- Treatment for late-stage melanoma is considerably more complicated with a lower chance of success and survival rates.