Topical photodynamic therapy (PDT) is effective in the treatment of certain non-melanoma skin cancers and is under evaluation in other dermatoses. Its development has been enhanced by a low rate of adverse events and good cosmesis. 5-Aminolaevulinic acid (ALA) is the main agent used, converted within cells into the photosensitizer protoporphyrin IX, with surface illumination then triggering the photodynamic reaction. Despite the relative simplicity of the technique, accurate dosimetry in PDT is complicated by multiple variables in drug formulation, delivery and duration of application, in addition to light-specific parameters. Several non-coherent and coherent light sources are effective in PDT. Optimal disease-specific irradiance, wavelength and total dose characteristics have yet to be established, and are compounded by difficulties comparing light sources. The carcinogenic risk of ALA-PDT appears to be low. Current evidence indicates topical PDT to be effective in actinic keratoses on the face and scalp, Bowen's disease and superficial basal cell carcinomas (BCCs). PDT may prove advantageous where size, site or number of lesions limits the efficacy and/or acceptability of conventional therapies. Topical ALA-PDT alone is a relatively poor option for both nodular BCCs and squamous cell carcinomas. Experience of the modality in other skin diseases remains limited; areas where there is potential benefit include viral warts, acne, psoriasis and cutaneous T-cell lymphoma. A recent British Photodermatology Group workshop considered published evidence on topical PDT in order to establish guidelines to promote the efficacy and safety of this increasingly practised treatment modality.

This study confirms that PDT is a useful treatment and that selected superficial BCCs and SKs respond well to PDT. The PDT 1200 light source proved capable of treating multiple lesions amounting to a 'field change' and also lesions up to 10 cm in diameter within an acceptable treatment time. Thus far, PDT has failed to become established as a routine treatment for small premalignant and malignant skin lesions as it has not proved superior to simple cheaper conventional therapies such as cryotherapy, curettage and cautery, topical chemotherapy with 5-fluorouracil, or surgery. However, PDT has become established as a treatment for selected cases in some centres. This study suggests a role for PDT in the treatment of large premalignancies, superficial BCCs and field change where existing treatments may be problematic.

No abstract

This is the first large-scale study to attempt to measure the impact of a range of photodermatoses on QoL. Photodermatoses have a major impact on QoL. This impact is highest in AP and PAD.