Skin cancer

Skin

Skin, the largest organ of the human body, has various functions:

• it protects the underlying tissues and organs from harmful external influences, such as infections and ultraviolet (UV) radiation
• it communicates with the brain about heat, cold, sensation and pain
• it ensures a constant body temperature

The skin consists of three layers. From the outside in, the layers are:

• the epidermis (or outermost skin)
• the dermis (or corium)
• the subcutis (or subcutaneous binding and adipose tissue)

The two most important cells of the epidermis are:

• squamous cells or keratinocytes
• pigment cells or melanocytes

Types of skin cancer

There are different types of skin cancer, depending on the cells from which they originate.

• actinic keratosis (pre-stage of spinocellular carcinoma, a type of skin cancer)
• basal cell cancer (also called basal cell carcinoma or basocellular carcinoma)
• squamous cell cancer (also called squamous cell carcinoma or spinocellular carcinoma)
• melanomas (a cancer of the melanocytes)

Actinic keratosis

Actinic keratosis (AK) is a benign lesion that develops in skin damaged by solar radiation (or X-rays, in rare instances). It is considered a precursor of spinocellular carcinoma, a type of skin cancer.

Actinic keratoses are harmless in themselves, but an evolution towards spinocellular carcinoma is estimated at 10 to 15% over an average period of ten years. Actinic keratoses may be present from the age of 40 but are increasingly common with increasing age and sun exposure. People who have a lot of recreational (sports, sunbathing) or professional (agriculture, construction...) sun exposure are particularly at risk. Pale skin types (blond or red hair, blue eyes) are also more sensitive.

Because of this risk of progressing to skin cancer, it is advisable to treat these lesions.

• In case of a limited number of lesions, cryotherapy is often chosen. With this technique, the skin is superficially frozen with nitrogen.
• For more extensive lesions, a field treatment with 5-FU, imiquimod or PDT may be appropriate.
• Stubborn lesions can be treated surgically.

Patients who have actinic keratoses carry sun damage in their skin and should therefore be very stringently protected against additional sun damage by regular use of a sun cream (SPF 50+) and protective clothing (hat, covering clothes).

Basal cell cancer

A basocellular carcinoma (BCC or sometimes 'baso' in short) is a malignant skin tumour. However, it is relatively harmless to general health because it never metastases. However, it often grows slowly but steadily and can grow into the surrounding and underlying tissues.

Superficial lesions can sometimes be treated with ointment (imiquimod, 5-FU) or PDT. Laser is also one of the possibilities.

Thicker or complexly growing lesions are preferably treated surgically.

Squameous cell cancers

A spinocellular carcinoma (SCC or sometimes 'spino' in short) is a malignant skin tumour. Unlike the basocellular carcinoma, a spinocellular carcinoma can also spread (metastasise) to the lymph nodes. However, the likelihood of this happening is rather small and is estimated at around 2 to 5%. The risk of metastasis increases with the size of the lesion, how developed it is and the site where it is located. Tumours in the face have a greater chance of metastasis than elsewhere on the body.

A spinocellular carcinoma must therefore be treated quickly and adequately. After diagnosis, an ultrasound exam is also offered in specific cases to rule out any glandular contamination.
Regular follow-up of the skin after diagnosis of spinocellular carcinoma is necessary.

Melanoma

Although melanomas develop in the skin just like basal cell cancer and squamous cell nuclei, they have a very different disease course. Melanoma is much less common than other skin cancers, but can be far more severe.

Melanoma is a form of skin cancer caused by melanin-containing pigment cells or melanocytes. A melanoma can arise from benign birthmarks. However, it can also come on 'spontaneously' from normal skin where no birthmark was previously noticed. Sometimes they can also appear in the mucous membranes, the rectum, the meninges and even in the eye.

In the case of melanomas, it is very important that the abnormality is detected and treated as early as possible. That is why every suspicious birthmark or other skin spot must be checked.

Treatment

The most important treatment of early-stage melanoma is surgery. Chemotherapy, immunotherapy, targeted therapy and radiotherapy are also deployed for malignant melanomas.

Removal under local anaesthetic

Surgery under local anaesthetic requires one or more injections into the skin with an anaesthetic. Lidocaine is generally used for this purpose. The injections are made with a fine needle which causes a briefly annoying, burning sensation. Soon after, the skin becomes insensitive to pain. Sensitivity to touch is retained, so it is quite normal that you still feel 'something is happening' without feeling any pain. The anaesthetic lasts an average of two to three hours after the injection.

The benefits of local anaesthesia are (among other things) that the patient:

• does not have to be on an empty stomach (fasting)
• does not require extensive preparation
• does not receive an IV
• receives outpatient treatment, meaning no hospital admission and once home after the operation, the patient can drive immediately
• does not have post-surgical nausea
• has automatic pain relief in the first few hours after surgery

Surgery

After it is marked, the skin is disinfected and then covered by a sterile covering.

A bandage will be placed after the procedure has been completed.

Your physician will discuss the aftercare with you in detail.

Photodynamic therapy (PDT)

PDT (photodynamic therapy) is a selective method for treating premalignant and malignant skin problems.

The technique uses a substance applied in cream form to the area to be treated and specifically absorbed by the tumour cells. The product is left to soak under bandages for three hours. Afterwards, the skin is illuminated with a bright red light that activates the absorbed substance that damages the tumour cells. The technique is particularly suitable for superficial lesions (<2 mm thick).

In the case of actinic keratoses, the product is often applied to an entire skin area to treat the lesions themselves and their early precursors in a specific area.

The exposure phase is often a painful part of the treatment, but it has a short duration (eight minutes per field). Often, taking paracetamol an hour prior to treatment can reduce all or part of the pain.

Depending on the type of lesion, one or more treatments are necessary:

• actinic keratoses: once per area, to be repeated after three months, if necessary
• basocellular carcinoma and Bowen’s disease: twice with one week in between

The success rates of this treatment are high, but not 100%. Alternatives include treatment with cryotherapy, 5-FU, imiquimod or surgery.

Damaging the cells causes a superficial crust to form that heals easily with a wound healing ointment and usually leaves a very discrete scar or no scar at all.

Imiquimod for local skin use

Imiquimod is used in ointment form within dermatology as a locally acting repellent stimulant. It is used to treat actinic keratoses, basocellular carcinoma and genital warts.

During use, superficial skin wounds and scabs often develop as a result of the death of the treated cells. This is a completely normal reaction inherent to the functioning of the product. The severity with which this happens varies greatly from one individual to another and usually starts only after a few days to a week of use.

You need not be afraid of this sometimes very pronounced reaction. If, for any reason, the reaction seems highly unusual, then contact your dermatologist.

The treatment schedule is different depending on the condition:

• actinic keratoses: three times a week for four weeks
• basocellular carcinoma: five times a week for six weeks
• genital warts (condylomas): three times a week for a maximum of 16 weeks

At the end of the treatment, a skin repair ointment is used to speed up the healing process.

Precautions to be taken when using imiquimod:

• always wash hands thoroughly after use
• if a nurse, an acquaintance or your partner helps you with the treatment, this person should wear gloves and wash hands thoroughly afterwards to avoid unnecessary exposure to the product.
• the skin lesions do not need to be covered during the treatment, unless otherwise indicated by your physician

The success rates of this treatment are high, but not 100%. Alternatives include treatment with cryotherapy, 5-FU, PDT or surgery.

5-Fluoro-uracil for local skin application

5-FU is used in ointment form within dermatology as a locally acting chemotherapeutic agent. It works by damaging fast dividing cells and is therefore used in the treatment of actinic keratoses, Bowen’s disease, basocellular carcinoma... but also for viral warts.

During use, superficial skin wounds and scabs often develop as a result of the death of the treated cells. This is a completely normal reaction inherent to the functioning of the product. The severity with which this happens varies greatly from one individual to another and usually starts only after a few days to a week of use.

You need not be afraid of this sometimes very pronounced reaction. If, for any reason, the reaction seems highly unusual, then contact your dermatologist.

Usually, the treatment is prescribed for three to four weeks, but this may be shorter or longer in specific cases. At the end of the treatment, a skin repair ointment is used to speed up the healing process.

Precautions when using Efudix:

• shall not be used in or handled by pregnant women
• always wash hands thoroughly after use
• if a nurse, an acquaintance or your partner helps you with the treatment, this person should wear gloves and wash hands thoroughly afterwards to avoid unnecessary exposure to the product.
• the skin lesions do not need to be covered during the treatment, unless otherwise indicated by your physician

The success rates of this treatment are high, but not 100%. Alternatives include treatment with cryotherapy, PDT, imiquimod or surgery.

Field treatment in case of actinic keratosis

Your physician may prescribe treatment for larger parts of the face or body. Such a treatment is usually chosen if the actinic keratoses infestation is pronounced. The great advantage of full-surface treatment ('field treatment') is that intermediate precursor lesions are also treated, so the effect is more thorough and longer lasting.

Treatment of basocellular carcinoma or Bowen’s disease.

In case of these lesions, the ointment should be applied to the lesion itself and to the first half centimetre surrounding it.

Multidisciplinary consultative body

To optimise each individual approach to skin cancer, dermatologists are part of a ‘MOC’ (Multidisciplinary Oncology Consultation). This is a multidisciplinary consultation where several physicians, including the GP, meet for discussion.

Integrated Cancer Centre in Ghent

Integrated Cancer Centre in Ghent

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Latest publication date: 08/01/2024