Skin cancer: melanoma

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What is it about ?

Human skin is made up of 3 layers:

  • the superficial layer, called the epidermis;
  • the middle layer, called the dermis;
  • the lower layer, called the hypodermis or subcutaneous connective tissue.

Most skin cancers develop in the epidermis.

Risk factors

You are more at risk of developing skin cancer if:

  • you have fair skin that is difficult to tan, you easily get sunburned, you have light eyes or hair;
  • you are exposing yourself too much to the sun or to ultraviolet (UV) rays from sunbeds;
  • you had sunburns, especially when you were a child;
  • you have a lot of ‘abnormal’ birthmarks;
  • you have ever had skin cancer;
  • someone in your family has had skin cancer (hereditary predisposition);
  • you are taking or have taken a medicine that weakens the immune system (immunosuppressive medicine).
Types of skin cancer

There are several types of skin cancer:

  • the basal cell carcinoma and squamous cell carcinoma (also called squamous cell carcinoma). These are the most common types of skin cancer (plus or minus 9 out of 10 cases);
  • the melanoma. It is a less common type of skin cancer (almost 1 in 10);
  • ofothers fairly rare types of skin cancer.

This patient guide talks about melanoma.

What is a melanoma?

A melanoma is therefore a type of skin cancer. It develops at the start of the pigment cells (melanocytes) of the surface layer of the skin (epidermis).

Melanoma usually appears on a ‘healthy’ area of ​​skin. About 1 in 3 melanomas develop from an already existing mole (nevus).

Melanomas are most common on parts of the skin that are exposed to the sun. But it’s not always the case. Melanomas can develop anywhere on the skin (scalp, under the nails, etc.).

Exposure to ultraviolet (UV) rays, from the sun for example, can trigger the development of a benign skin spot into melanoma.

At whom and how often ?

Melanoma is the 6e most common cancer in Belgium. In 2018, 3,489 people developed melanoma.1

The number of melanomas has increased in recent years. The main reason is that people expose themselves to UV rays more often and for longer (sunbathing or sunbeds).

How to recognize a melanoma?

A melanoma usually looks like a spot:

  • raised stain;
  • stain that bleeds easily when scratched;
  • dark brown to black stain. The spot can also be red, blue, gray, or the color of the skin. The staining also extends beyond the tumor, further down the skin;
  • central spot surrounded by other small spots (satellite lesions).

You should also think about melanoma if a mole (nevus):

  • grows, especially if it is growing rapidly;
  • changes color;
  • bleeds;
  • develops sores;
  • has a discharge of pus;
  • tickles;
  • it hurts ;
  • if small brown spots appear all around (satellite lesions).

How Does Your Doctor Diagnose Melanoma?

To make the diagnosis of skin cancer, your doctor will carefully examine the suspicious spot. Sometimes he will use a dermatoscope: it’s a kind of magnifying glass that allows you to examine the stain in detail.

  • What is her color ?
  • What is its shape?
  • What is the appearance of its surface?
  • What is its size (diameter of the spot)?
  • Where in the body is it located?

Appearance is not sufficient to diagnose melanoma.

Your doctor will therefore assess your risk of skin cancer on the basis of the following elements (risk factors):

  • your skin type (there are 6 types of skin, also called phototypes);
  • signs of solar keratosis;
  • your sun exposure or sunburn in the past;
  • if you have ever had skin cancer;
  • if anyone in your family has had skin cancer;
  • if you smoke;
  • if you are taking or have taken any medicine that suppresses your immune system (immunosuppressive medicine);

Your doctor or skin specialist (dermatologist) can take a picture of the stain and note its dimensions. After 6 months, he will look to see if the stain has grown or changed color.

If in doubt, your doctor will remove the stain, or a small part of it, and send it to the laboratory for further examinations (skin biopsy).

What can you do ?

Limit your exposure to UV (ultra-violet rays)

Most melanomas are caused by too much exposure to UV rays or by too much sunburn. The most important thing is therefore good prevention.

  • Do not expose yourself too much to the sun:
    • don’t spend too much time in the sun;
    • stay in the shade during midday as this is when the sun is strongest.
  • Protect your skin as much as possible:
    • use sunscreen with a high protection factor:
      • minimum 30, certainly for people with fair and sensitive skin;
      • 50 for children;
    • use enough cream, apply it at least every 2 hours;
    • wear clothing that sufficiently covers your skin.
  • Avoid the sunbed.
Auto control

Check your skin regularly for spots.

  • Is a spot different from your other moles?
  • Does a new stain suddenly appear?

So be very careful.

The ABCDE rule makes it possible to detect a suspicious stain.

A stain is suspect if:

  • A – Asymmetry: the spot is asymmetrical, it has an irregular shape or thickness;
  • B – Edges: the stain has irregular edges;
  • C – Color: the stain has several colors;
  • D – Dimension: the diameter of the spot is greater than 6 millimeters;
  • E – Evolution: the stain evolves:
    • it changes rapidly in size, shape, color or thickness;
    • she bleeds easily;
    • she develops sores;
    • it tickles (itches);
    • it hurts.

Do you notice a suspicious stain? It requires further examination (see below). Contact your doctor.

What can your doctor do?

Skin biopsy

Your doctor will remove (or have removed) any suspicious stains. This is called a biopsy. It will be analyzed under a microscope.

If the microscopic exam shows it is melanoma, you will be referred to a surgeon.

  • The surgeon will remove a larger piece of skin:
    • up to 1 cm around the spot if the melanoma is superficial;
    • up to 5 cm around the spot if the melanoma is larger and deeper.
  • The surgeon will often remove the nearest lymph node (sentinel node) to see if the melanoma has invaded it (metastasized);
    • if the lymph node is affected, you will undergo a special scanner (PET-scan of the whole body) to detect possible other metastases;
    • the surgeon usually removes other lymph nodes afterwards.
  • The surgeon can suggest medication.

The surgeon plans a new operation if:

  • the melanoma comes back (recurs);
  • metastases appear on the skin.
Regular

Good follow-up after treatment for melanoma is very important.

The follow-up is mainly used to detect sufficiently early recurrences in the skin or lymph nodes:

  • a recurrence of melanoma may present as a lump under the skin (subcutaneous nodule) that is darker;
  • a recurrence in the nodes is presented by an increase in the size of the neighboring lymph nodes.

Follow-up visits usually take place every 3, 6 or 12 months for at least 5 years. The frequency of check-ups depends on the size of the melanoma, whether it has spread to the lymph nodes and other metastases.

During this follow-up, the doctor is also interested in the general state of health. He examines the site of the operation and the lymph nodes.

Want to know more?

Sources