Photodynamic therapy

This is used to treat skin cancer: and skin damaged by excessive sun exposure which is at high risk of becoming cancerous. It works by directing a beam of light onto a mole, lesion or affected area of skin which destroys cancerous cells within.

It is used to treat Bowen’s disease, basal cell carcinoma and solar keratosis (pre-cancerous growth).

What does photodynamic therapy do?

A light sensitive chemical is applied to the skin followed by the use of a particular wavelength of light which is aimed at the target area. The light causes certain changes within the skin which clears the site of the infection or cancerous growth.

Photodynamic therapy procedure

This procedure is performed at a dermatology clinic or department and takes a few hours to complete. Your skin is checked and any scabs or crusts removed.

A light-sensitive cream (known as a photosensitiser) is applied to the target area of skin. This is covered with a dressing and left for up to 3 hours which gives it time to be absorbed by the skin. The dressing is then removed and the cream wiped off. The target area of skin is cleaned.

A bright red light is shone onto the target area of skin for 15 to 45 minutes. The treated area is then covered with a dressing which is left in place for 2 days.

After a couple of days you can remove this dressing. Wash the treated area as normal but dry it gently, e.g. pat it dry. A scab will have formed over the treated skin so take care not to dislodge this as this will prevent healing. Do not pick or scratch this either.

Wear a suncream with a high sun protection factor (SPF) when outside to prevent sunburn. Avoid swimming until otherwise directed.

Your GP or dermatologist will advise you about caring for your skin following this treatment.

Who is not suitable for photodynamic therapy?

This treatment is not recommended for pregnant women or anyone suffering from porphyria (a disorder where the skin is extremely sensitive to sunlight).

Side effects of photodynamic therapy

Side effects of this treatment include:

  • Formation of ulcers
  • Blisters
  • Swelling
  • Pain
  • Infection

These are short term only and common with many other similar procedures such as phototherapy.

Long term effects include scarring, colour change to the skin and treatment failure. Success is not always guaranteed.