Photodynamic therapy (PDT) is one of the most effective non surgical treatments for Solar Keratosis, Superficial Basal Cell Carcinoma and In Situ Squamous Cell Carcinoma and Bowen’s Disease. PDT is also sometimes used for facial rejuvenation and to treat moderate acne. It is particularly appropriate in the management larger areas of skin that have widespread, less distinct, thin skin cancers or pre-cancerous patches. These are most commonly on parts of the face, scalp and ears exposed to prolonged sun damage.
Bristol Plastic Surgery is currently the only provider of this treatment in Bristol.
The treatment has two components. A special cream is applied to the whole area of concern. This cream contains an inactive and harmless agent called a photosensitiser which is only activated by the second component which is a special light source of a certain wavelength (usually in the red spectrum).
The cream is applied and the photosensitiser is allowed to absorb into the skin. When the light is applied, the photosensitiser, now within the cancerous and precancerous cells, is activated, causing oxygen molecules to become “excited”. These “excited oxygen molecules” then selectively destroy the affected cells.
This is an outpatient procedure performed by your surgeon or specialist nurse. The whole process takes about four hours. The special cream may contain peanut oil and you should advise your doctor or nurse if you have an allergy. You should also warn them if you suffer from porphyria which is a light sensitive disorder.
The area is first prepared by removing loose flakes and crusts and then the cream is applied and covered with a dressing. This is left undisturbed for 3 hours to allow the active ingredient to be absorbed and you can leave the clinic during this time. Back in the treatment room, the dressing is removed and a bright red light is shone on the treatment area for between 10 - 45 minutes. The area is then redressed and left covered for 2 days.
You may experience discomfort while the light is being applied. This is usually well tolerated but If this is too much, the treatment can be paused and cold water sprinkled on the skin to ease the discomfort. In selected cases when large areas are treated at once, local anaesthetic may be administered before the application of the red light.
Until the dressing is removed, keep the area dry. Thereafter, you may wash and shower as usual. Take care not to rub the treated area. Dry by patting gently. A scab will form over the area in the next few days and you must take care not to scratch or abrade this area. A high factor sunscreen should be applied to the area and too much sun exposure should be avoided.You should avoid swimming until the area is fully healed.
You may experience some discomfort and itching and require to have some painkillers in the days following treatment. There will be some inflammation of the area which will become pink and puffy. The area may ooze but this will settle within a few days. Healing will take several weeks and varies according to the body area treated. Thereafter, careful protection against further sun exposure must be rigorously followed by seeking shade in strong sunlight, using high protection sun factors and protective clothing.
Scarring is possible after PDT and care must be taken to avoid scratching or injuring the area in the first few weeks. The area itself may undergo some colour change and can be either darker or paler after treatment.
The area will have to be monitored and where treatment has not been effective, the treatment may require to be repeated or an alternative surgical option may be needed. The main advantage of this treatment is that ill defined widespread areas can be treated and extensive surgery avoided.
Please see this Youtube clip on Photodynamic Therapy for more information.