PDT may be used to treat large area Actinic Keratosis lesions on the face, scalp and body or individual non-melanoma skin cancers such as Basal Cell Carcinomas.
PDT for BCC’s
When treating individual BCC’s or actinic keratoses, photodynamic therapy (PDT) is a 2-step procedure involving the application of a photosensitizing cream, Methyl Aminolevulinate (Metvix), to the cancerous lesion before exposing it to a 630nm red light source. This light promotes selective destruction of abnormal cancerous cells while sparing any damage to adjacent healthy structures.
Not all types of BCC’s are suitable for this treatment. If the tumour is deeply infiltrating or a morphoeic type, then surgery remains the treatment of choice. Photodynamic therapy is suitable for superficial & nodular Basal Cell Carcinomas when surgery is considered inappropriate. Patients with multiple lesions or has a BCC in a cosmetically sensitive area would also benefit from this treatment.
The biggest advantage of PDT is that there is minimal or no scarring associated with the treatment. In addition, treatment compliance is assured with PDT as the patient only has to come twice for treatments with little at home hassles. Furthermore, patients have less treatment related anxiety, less downtime from work, sport and other activities. There is a low risk of infection following PDT.
PDT for Actinic Keratoses
When treating large areas of skin affected by large numbers of actinic keratoses (e.g. whole face), topical 20% 5-aminolevulinic acid (5-ALA) solution is applied to the whole area by the nurse or physician. This is converted into an endogenous photosensitiser once absorbed into the skin. It concentrates around cells with rapid cell turnover such as cancerous cells, pre-cancerous cells and sebaceous glands. 1 to 3 hours later, medicated areas are exposed to strong red light, which activates the 5-ALA. The treatment selectively destroys actinic keratoses, causing little damage to surrounding normal skin, although some swelling often occurs.