Some topical papers:
Dragieva G, Scharer L, Dummer R, Kempf W. Photodynamic therapy--a new treatment option for epithelial malignancies of the skin. Onkologie. 2004 Aug;27(4):407-11.
Department of Dermatology, University Hospital of Zurich, Switzerland.
Photodynamic therapy (PDT) is based on the activation of a photosensitizer by illumination with visible light, leading to photochemical tissue destruction or immunomodulation. The greatest disadvantage of systemic administration of photosensitizers is cutaneous photosensitization of the patients, which lasts for some months. An alternative approach for epithelial precancerous lesions, such as actinic keratoses and Bowen's disease, as well as for superficial skin tumors, such as basal cell carcinomas, is the topical application of sensitizers, especially 5-aminolevulinic acid. Topical PDT causes selective tissue necrosis and tumor destruction and produces excellent cosmetic results. The following article summarizes the main principles of PDT and provides a synopsis of the present status of the use of PDT for epithelial skin malignancies.
Naidenov N, Dencheva R, Tsankov N. Recurrence rate of Basal cell carcinoma after topical aminolevulinic Acid-based photodynamic therapy. Acta Dermatovenerol Croat. 2004;12(3):157-61.
Department of Dermatology; Medical University #1 G. Sofiiski Str. Sofia, Bulgaria.
Photodynamic therapy with topical 5-aminolevulinic acid is an alternative to the surgical treatment and radiotherapy of different non-melanoma skin cancers, especially basal cell carcinoma (BCC). Advantages of photodynamic therapy include selective destruction of the tumor; lack of toxicity; possibility to perform the procedure easily at any part of the human body; and single application, which is comfortable especially for elderly patients. Photodynamic therapy can be performed repeatedly without side effects and the cosmetic outcome is excellent. It is very convenient for large and multiple lesions and is the only choice for patients contra-indicated for surgery or radiotherapy. Disadvantage of photodynamic therapy is a relatively high recurrence rate of BCC after a single photodynamic procedure, ranging between 0% and 100%. We followed up a group of 60 patients with BCC who were treated with a single photodynamic procedure. The recurrence rate in our patients was 35%. The most probable reasons for the relatively high recurrence rate were the size, localization, and histological type of the lesion; chemical structure of a photosensitizer used; the light source; and the dose. The lowest recurrence rate was observed in superficial BCCs
