Skin cancer: basal cell and squamous cell carcinoma (squamous cell)

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 basal cell and squamous cell carcinomas.

What is basal cell carcinoma?

It is the most common skin cancer in people with fair skin. People who develop basal cell carcinoma for the first time are on average 65 years old.

It is the least aggressive cancer because it grows slowly, spreads locally, but does not metastasize to other areas in the body.

It is due to too much exposure to ultraviolet (UV) rays, like other skin cancers.

What is squamous cell (squamous cell) carcinoma?

Squamous cell carcinoma very rarely affects people under the age of 45. People who develop squamous cell carcinoma for the first time are on average 74 years old.

It can metastasize to nearby lymph nodes.

It is due to too much exposure to ultraviolet (UV) rays, like other skin cancers.

How to recognize a basal or squamous cell carcinoma?

Pre-cancerous lesions

Some skin changes can appear before skin cancer develops. We are talking about pre-cancerous lesions. For example :

• an atypical skin lesion, which often looks like a wart or eczema patch;
• a lesion that grows, bleeds, or does not heal.

How to recognize basal cell carcinoma?

Basal cell carcinoma mainly occurs on the face or on a part of the body that has been exposed to strong sunlight.

Basal cell carcinoma looks like this:

• a small, smooth and transparent ball which grows very slowly;
• brown, pink, skin color to dark red;
• sometimes you can see thin blood vessels.

After a while, a small ulcer appears in the middle, with a scab over it and a pearly ring around.

On the torso, it may look like a patch of scaly eczema.

How to recognize a squamous cell carcinoma (squamous cell)?

Squamous cell carcinoma mainly develops in areas that have been exposed to strong sunlight, such as the face, back of the hand, and neck. It can also develop on the lips.

Squamous cell carcinoma looks like this:

• at the beginning, a small red-pink ball;
• sometimes with a scaly crust;
• no blood vessels can be seen and it is not pearly. This is what makes the difference with basal cell carcinoma.

On the lips, the appearance is different. We can see a white spot that slowly grows and is covered with scales.

How does your doctor diagnose basal cell or squamous cell carcinoma?

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 ?

Most basal cell and squamous cell carcinomas are caused by too much exposure to UV rays or by too frequent sunburn. The most important thing is therefore good prevention.

Limit your exposure to UV (ultra-violet rays)

• 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

• Do you see abnormal (atypical) eczema patches or other atypical lesions that do not heal or are progressing poorly?
• Are they found in areas of your skin that have been heavily exposed to the sun, such as the face, back of your hand and neck?

In this case, go to your doctor for an evaluation.

What can your doctor do?

There are several possibilities for treatment. The choice depends on:

• the type of cancer;
• the location and size of the lesion;
• possible metastases;
• your age;
• of your wishes.

Usually, skin cancer is removed surgically, sometimes under local anesthesia.

Your GP can remove (excise) the smallest lesions. A doctor specializing in plastic surgery will remove the largest lesions and those that are placed in places where it is more difficult to intervene (eyelids, nose, ear canal). The doctor removes the lesion and a few small millimeters of healthy skin around the lesion.

In the case of basal cell carcinoma, removing the carcinoma is usually sufficient.

In the case of a squamous cell carcinoma, several lymph nodes are also often removed to test for metastases.

Basal cell carcinoma is sometimes treated with cold (cryotherapy). It can also be treated with a cream that destroys cells (local chemotherapy) or a cream that stimulates the immune system (immunotherapy).

There are still other treatment possibilities, such as

• radiotherapy;
• photodynamic therapy: a treatment which consists of applying a substance to the lesion and then exposing it to a specific light which then destroys the lesion;
• electrocoagulation: a treatment that involves destroying the lesion, usually with an electric current.

Want to know more?

• Skin cancer (non-melanoma) – Fondation contre le cancer
• Basal cell carcinoma (image) – DermIS – Dermatology Information System

• Skin type and UV index – Fondation contre le cancer
• FAQ’s UV – Foundation against cancer

Sources

• Foreign clinical practice guide ‘Malignant epidermal tumors (basal cell carcinoma and carcinoma of squamous epithelium cells)’ (2000), updated on 30.05.2017 and adapted to the Belgian context on 12.04.2019 – ebpracticenet
• Foreign clinical practice guidelines ‘Suspicious skin abnormalities’ (2017) – NHG – Nederlands Huisartsen Genootschap
• Skin cancer (non-melanoma) – Fondation contre le cancer