Photodynamic therapy with systemic administration of photosensitizers in dermatology

We have reviewed the results of clinical investigations into the use of photodynamic therapy (PDT) with intravenous injection of hematoporphyrin derivative (HpD), Photofrin (PF) and Sn-protoporphyrin (Sn-Pp) or oral administration of delta-aminolevulinic acid in the treatment of skin cancers and/or psoriasis. Bowen's disease was highly responsive, provided that adequate light and HpD or PF doses were delivered. In contrast, poor results were shown for squamous cell carcinoma, and the rates of complete response of basal cell carcinoma ranged between 0% and 100%. Treatment failures could be related to the delivery of low drug and/or light doses, but differences in the thickness and pigmentation of the treated lesions may play a relevant role. Good palliation was almost always achieved in patients affected by primary and secondary breast carcinomas, although complete eradication of tumors was very rare. PDT is a very promising treatment modality for both Mediterranean and HIV-related Kaposi's sarcoma, because it appears to be effective, can be repeated and is not associated with immunosuppressive activity or significant systemic toxicity. PDT of psoriasis with low doses of Sn-Pp, HpD or PF plus UVA light and PF plus 630 nm light proved to be effective and was associated with mild, dose-related and reversible photosensitivity.