European guidelines for topical photodynamic therapy part 2: emerging indications – field cancerization, photorejuvenation and inflammatory/infective dermatoses

In addition to established indications in non-melanoma skin cancer in immunocompetent patients, photodynamic therapy (PDT) has been studied for the treatment, and possible prevention, of superficial skin cancers in immunosuppressed patients. As a topical photosensitizer can be applied over large areas, PDT is also increasingly used for field cancerization in photodamaged skin, with evidence of potential to delay the development of actinic keratoses and basal cell carcinoma, although direct evidence of prevention of invasive squamous cell carcinoma remains limited. PDT has been studied in patch/plaque-stage cutaneous T-cell lymphoma, with efficacy more likely in unilesional disease. Accumulating evidence supports the use of PDT in acne and several other inflammatory/infective dermatoses including cutaneous leishmaniasis, although protocols are still to be refined. Despite proven efficacy, PDT is not widely used in viral/genital warts, where pain during treatment can be intense. PDT is a therapeutic option for photorejuvenation, with improvement in fine wrinkles, mottled hyperpigmentation, roughness and sallowness reported.