ABSTRACT
BACKGROUND: Aminolevulinic acid (ALA) and light irradiation is a treatment option in basal cell carcinomas (BCC). The development of ALA-esters with potential for greater penetration depth promises higher therapeutic success. In a pilot study, we hypothesized that the cytotoxic effect of methyl-ALA (mALA) photodynamic therapy (PDT) leads to a higher success rate compared with ALA-PDT when both are topically applied in a thermogel. METHODS: Twenty-four patients with 112 superficial BCC were treated with either 10% ALA- or mALA-thermogel. After an accumulation time of at least 3h, the lesions were illuminated with a diode laser. The power density was 0.1W/cm(2) and the energy density was 120J/cm(2). After intervals of 12 weeks and 6 months, the therapeutic efficacy was assessed by clinical examination. RESULTS: Sixty percent of the tumors were treated successfully in the first session. All but 3% of the remaining tumors could be treated with a second or third course of therapy. CONCLUSION: Although mALA should have a greater penetration depth, the therapeutic outcome of this preliminary study showed no difference between treatments. The final proof of this preliminary result will require further study.
ABSTRACT
PURPOSE: The benefit for organ recipients is still counteracted by the side effects of immunosuppression. Among other effects, there is a 50-250 times increased risk of developing malignant skin tumours. Because these malignomas are known to develop particularly aggressivly, there is a special need for an efficient therapy. Here we demonstrate the treatment response to aminolaevulinic acid (ALA)-based photodynamic therapy (PDT) in these patients. METHODS: Five organ recipients with multiple tumours of the face were multifocally treated with ALA-PDT (32 tumours in all). After topical application of ALA using a thermogel, irradiation was done with a 635 nm diode laser (Ceralas 635, Biolitec, Jena, Germany). After intervals of 2 weeks, 4 weeks, and 12 weeks, therapeutic efficacy was assessed. RESULTS: There was complete remission in 24 tumours (75%). In six tumours (18.8%) a second or third PDT session was necessary for complete clinical remission. In two tumours (5.6%, invasive squamous cell carcinomas) the lesions were refractory to PDT. CONCLUSIONS: ALA-PDT is a valuable therapeutic alternative for the treatment of multifocal skin tumours in organ-transplanted patients. Furthermore, we see a growing role of ALA-PDT also for patients with frequently relapsing tumours of the skin with known genetically determined tumourigenesis (Gorlin-Goltz syndrome).
