Photodynamic therapy (PDT) is a new form of treatment used to treat skin tumours such as actinic keratosis and basal cell cancer (BCC, basalioma). The new treatment involves spreading a cream on the surface of the tumour and then illuminating this area after a set period of time. When the area is illuminated with normal red light, a photo-chemical reaction is triggered, and the tumour cells are destroyed. The healthy skin around the tumour is not significantly affected.
Treatment
The skin lesion is prepared for treatment by removing crusts and scales and roughening the surface. This makes it easier for the cream and light to penetrate deeply into all parts of the lesion. The cream is applied with a spatula, in a 1 mm thick layer that covers the lesion and 5-10 mm of the surrounding skin. After application, the area is covered with an occlusive dressing for three hours. The dressing and cream are then carefully removed using a saline solution, and the treated area is exposed to red light for about 10 minutes. To protect the eyes from the intense light, the patient must wear protective eye shields throughout the illumination period. During the exposure to the light, the patient may experience a feeling of warmth and slight discomfort. In some cases, this discomfort may continue after treatment. Paracetamol (two Alvedon® or Panodol® tablets) may be taken as required.
Subsequent to treatment
After treatment, the skin turns red, and blisters and crusting may appear after a few days. Lesions can be protected with dry compresses as required. The skin may also swell slightly, which is particularly noticeable on the face. Scabs will then start to form on the wound - indicating that the healing process is underway. The entire healing process for the lesion takes approximately 2-4 weeks. The area treated should be protected from sunlight on the day of treatment and for the first few days afterwards.
Cosmetic effect
The healthy skin is not affected. Photodynamic therapy generally produces good cosmetic results, because the treatment results in less scarring than conventional methods. This form of therapy is therefore very good for treating skin lesions on cosmetically sensitive areas such as the face, chest, back and upper arms. Photodynamic therapy can also be used in locations where conventional methods are difficult to use. One example is that of tumours on the lower leg, where cryosurgery is not appropriate, and where conventional surgery may require skin grafts. The skin reddens after the lesion has healed. This redness gradually disappears. In a very few cases, the skin may become darker. This usually disappears in 1-2 years.
Advice about exposure to sunlight
Actinic keratosis and basal cell cancer are both caused by exposure to solar radiation. The risk of new lesions is high, and increases on continued exposure to sunlight. Therefore, it is very important to change your approach to sunlight. Clothing and shade are recommended. If you use sun creams, these must contain titanium dioxide or zinc oxide. To help the "scar" in the treated area to heal as attractively as possible, and to prevent permanent redness, you must be very careful as regards exposure to the sun.