Photodynamic therapy, or PDT for short, is a relatively new treatment for skin cancer which is recommended by the UK’s National Institute for Clinical Excellence as a first line of treatment for certain types of skin cancer including basal cell skin cancer and also some types of pre-cancers such as Bowen’s Disease of the skin and also solar (or actinic) keratoses.
Photodynamic therapy (PDT) avoids surgery and surgical scars. This is especially important because the majority of basal cell skin cancers and solar keratoses will appear in areas which have been exposed to the sun and the majority of these on the head and neck. PDT is a quick, easy, scar-less way of dealing with the most common skin cancer in the UK.
Very simply a special cream, preferentially absorbed by skin cancer cells is applied to the target area after diagnosis and then, after an interval a very bright light is used to illuminate the area. A slight tingling is felt whilst the light is applied. It is not painful. The skin cancer or pre-skin cancer will then crust and fall off in the next week or two, leaving fresh healthy skin beneath.
Skin cancer is the commonest form of cancer in the UK and of the non-melanoma type skin cancers, a particular type of skin cancer called Basal Cell Cancer (BCC) is the commonest.
Basal cell skin cancers are strongly related to ultra-violet light exposure, either through natural sunlight or more commonly these days because of artificial ultra-violet light in sun beds.
Until recently (around 2006) surgery or liquid nitrogen cryo-therapy was the recommended treatment. In 2006 though, after considering evidence from a large number of studies, the UK’s National Institute for Clincial Excellence (NICE) recommeded the use of Photodynamic Therapy (PDT for short) for treatment of basal cell skin cancers (BCC) and pre-malignant or pre-cancerous skin lesions including solar (or actinic) keratoses and also Bowen’s Disease of the skin.
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 generally does not result in scarring. It is now the preferred treatment for many skin cancers in the UK. Not all non-melanoma skin cancers are suitable for PDT. Our Consultant Dermatologist, consults with all our patients and tailors an individual treatment regime for each patient.
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.
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. Our Consultant Dermatologist, Dr Lucia Pozo-Garcia personally consults with all patients treated with PDT at Freedomhealth.
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 for the public here.
How is 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 PDT 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 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.