Photodynamic Therapy (Pdt) For Skin Cancer In London

Photodynamic therapy or PDT for short is a new way of treating some skin cancers and certain other pre-cancerous skin lesions. These are basal cell carcinoma’s, Bowen’s Disease and also actinic (or solar) keratosis.

PDT is quick, easy, and does not result in scarring. It is now the preferred treatment for many skin cancers in the UK. Photodynamic therapy is not the preferred treatment for squamous cell skin cancers as these have a high chance of recurrence and we want to be sure that the treatment has succeeded.

Putting it very simply, photodynamic therapy for skin cancers involves applying a special light sensitizing cream to the affected area and a little of the surrounding area and then after a short while shining a bright light onto the treated area. The cells which have absorbed the chemical and are then subject to the bright light will die off leaving fresh normal skin to grow in its place. Normal cells are left relatively undamaged. This is because PDT affects mainly fast growing skin cancer or pre-cancer cells.

Until recently, standard treatments for these particular skin cancers have been either destructive, for example using liquid nitrogen, or surgical. Both of these treatments has its advantages but a major disadvantage of surgical treatments has been the resulting scar left by the surgical cut and stitches. Liquid nitrogen spray or cryotherapy for skin cancer will destroy the tumour cells but is not terribly refined and will destroy other normal tissue also. Photodynamic therapy avoids scars.

Photodynamic therapy (PDT) is available on the UK NHS in some centres but relatively few and for those NHS units there is a long waiting list. The problem is the usual one of funding. NHS units are limited by their funding and so can see limited numbers of patients. Consequently large numbers of patients are sent via the surgical route and get what is now considered to be good but not the best treatment.

PDT can be used for treating other cancers but at Freedomhealth we only treat designated types of skin cancer and pre-malignant or precancerous lesions as recommended by the UK’s National Institute for Clinical Excellence (NICE). We operate under stringent conditions imposed by the Care Quality Commission and are subject to annual re-licensing and approval.

NICE issued Guidance in 2006 saying that there was good evidence to support the use of PDT for treatment of basal cell cancers, Bowen’s Disease and also solar or actinic keratoses. NICE said that photodynamic therapy for skin cancers was of particular use in situations where a person may need a lot of surgery – for example where there was a large and not too deep skin cancer, or where there were multiple cancers. An obvious use of PDT is for skin cancers that are visible on the face or neck and where a surgical scar would be equally disfiguring as the tumour. You can download a pdf of the NICE Guidance here.

Basal cell skin carcinoma’s or cancers are very common indeed with skin cancers as a whole being the most common cancer in the UK and of these around 80% of the skin cancers which are not melanoma’s will be basal cell cancers. Basal cell skin cancers are caused primarily by exposure to sunlight. Australians have the highest rates of basal cell skin cancers in the world. Other risk factors include fair skin, blue eyes, red or blonde hair and intermittent intense exposure to sunlight or artificial ultra-violet radiation such as sun beds. One a person has a basal cell skin cancer then the chances of another appearing will be increased by 10 times compared with the general population.

How is PDT (photodynamic therapy) for skin cancers used?

The type of skin cancer is identified using a special magnifying glass called a dermatoscope. This allows the specially trained clinician to correctly identify the skin lesion as a basal cell cancer or as a pre-malignant skin lesion such as Bowen’s disease or an actinic keratosis.

In addition, the clinician will take either a painless scrape from the lesion or a special very thin sample of tissue called a biopsy which confirms the diagnosis and in the case of the skin biopsy, the depth of the tumour, to make sure that it is the correct diagnosis and also confirms the depth is ideal for treatment. These samples are sent to our laboratory for analysis which takes a few days.

Once the diagnosis is confirmed by the laboratory then treatment with photodynamic therapy for your particular type of skin cancer can begin.

A light-sensitising cream made up of 5-aminolaevulinic acid (ALA) tradename Metvix, is applied to the target area after the crusting debris has been gently removed. The area is covered with a dressing for three to six hours and then the area is subjected to a strong light for up to 45 minutes or so. A slight tingling is felt whilst the light is being used. A crusted area will then remain and will slowly fall off during the next week or two, depending on the size of the original lesion.

A second or third treatment is sometimes needed.