Principles of Photodynamic Therapy
Topical photodynamic therapy is widely used for the treatment of superficial non‐melanoma skin cancer and dysplasia and has been shown to be at least as effective as non‐surgical standard comparators such as topical fluorouracil and cryotherapy. British and European guidelines are available for its use, and treatment is undertaken on an out‐patient basis and is generally well tolerated, with the exception of pain during irradiation in a significant proportion of patients. Optimization of treatment regimens to improve efficacy and reduce side effects have included refinements in pro‐drug development and delivery and in the methods of light delivery, in particular using reduced irradiance regimens. The use of topical photodynamic therapy (PDT) has also been applied to a wide range of other diverse skin diseases including acne vulgaris and recalcitrant viral warts and it may have a role in some of these conditions, although further studies are required. It is important that topical PDT services are widely available in dermatology, particularly to those involved in skin cancer management, through the multidisciplinary team, and that standards and clinical governance for PDT are established.
Keywords acne, actinic keratosis, basal cell carcinoma, Bowen disease, efficacy, fluorescence, irradiance, light‐emitting diode, LED, pain, photodynamic therapy, photosensitizer, pro‐drug, visible light