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Patient Information Leaflet

Photodynamic Therapy

What are the aims of this leaflet?

This leaflet has been written to help you understand more about photodynamic therapy – what it is, what is involved, what the potential side effects are, and where to find out more about it.

What is photodynamic therapy?

Photodynamic therapy (PDT) is a technique for treating skin cancers and sun-damaged skin which might one day turn cancerous (pre-cancers). In PDT a light beam activates a cream which has been applied to the abnormal skin. This treatment kills the abnormal cells in the skin.

How does photodynamic therapy work?

PDT involves the use of a light-sensitive chemical (called a photosensitiser). This photosensitiser is, by itself, harmless. When light of a certain wavelength (usually red light) is shone onto skin to which the photosensitiser has been applied, the photosensitiser is activated. This causes changes in the oxygen molecules within the abnormal skin cells. These “excited” oxygen molecules kill the cells. Only the area of skin exposed to the light source will be damaged.  

What skin conditions can be treated with photodynamic therapy?

PDT can be used to treat various skin conditions including:

• Thin basal cell carcinomas
• Bowen’s disease (in situ squamous cell carcinoma), a pre-cancer.
• Actinic (solar) keratosis – early sun-damage, a pre-cancer

For further information about these conditions, please refer to the appropriate patient information leaflets.

What does photodynamic therapy for skin lesions involve?

PDT is an outpatient procedure, and will be done by your doctor or nurse. It takes several hours to complete. The first step is to apply a cream containing the PDT medicine to the area that needs to be treated. If necessary, any loose scale or crusts will be removed first. A dressing will then be applied over the cream and you will be asked to return in about 3 hours. This wait is to allow the PDT medicine to be taken up by the skin cells and to be converted into the active medicine by the skin. The cream is then wiped off and the area cleaned. Then, a bright coloured light is shone onto the treatment area for approximately 10 to 45 minutes (the precise time will be determined by your doctor or nurse). After the treatment has been completed, a dressing will be applied for about 2 days, to prevent any further exposure to light.

How should the treated area be cared for?

Your doctor will explain how you should care for the treated areas. It is usually suggested that, after the dressing has been removed, you can wash, bathe or shower as usual. Do not rub the treated area, but gently dab it dry. Within a few days, a scab will form, and healing will take several weeks (depending on which part of the body has been treated).

What reasons might prevent you having photodynamic therapy?

• PDT is not recommended if you are pregnant.
• The PDT cream may contain peanut oil, so tell your doctor and nurse if you are allergic to peanuts.
• PDT is not recommended if you have porphyria (a light-sensitive disorder).

Do I need to avoid anything whilst having photodynamic therapy?

It is best to avoid swimming until the treated area is fully healed.

What are the potential side effects of photodynamic therapy?

The short-term side effects of phototherapy include:

• Pain. When the red light is shone onto the skin, the treated area may hurt. If it is too uncomfortable, your doctor or nurse may suggest pausing treatment for a while, or a local anaesthetic injection may be recommended. After completion of treatment, discomfort and itching may last for a few days, and may require pain-killers.
• Inflammation. The treated area may initially become pink and puffy, and may ooze a little: this is a normal reaction. It settles within a few days.
• Blistering and ulceration. The treated area may occasionally blister or ulcerate.
• Infection. If the treated area becomes red, swollen and painful, an infection may have developed, and you should contact your doctor.

Potential long-term side effects of phototherapy include:

• Scarring. There may be some scarring after PDT.
• Colour change. The skin may be left darker or lighter after PDT.
• Treatment may not be effective, or the condition may come back again. If this happens, you may be offered further PDT, or an alternative type of treatment may be recommended.

Where can I get more information about photodynamic therapy?

You can find more information about photodynamic therapy on the following websites:

www.cancerbackup.org.uk/Treatments/Othertreatments/Photodynamictherapy
www.cancerhelp.org.uk
http://dermnetnz.org/procedures/photodynamic-therapy.html

The British Skin Foundation fund vital research into all skin diseases.  To find out how you can help, please visit the British Skin Foundation website here.

This leaflet aims to provide accurate information about the subject and is a consensus of the views held by representatives of the British Association of Dermatologists: its contents, however, may occasionally differ from the advice given to you by your doctor.

BRITISH ASSOCIATION OF DERMATOLOGISTS
PATIENT INFORMATION LEAFLET
PRODUCED SEPTEMBER 2009