Photodynamic therapy with delta-aminolevulinic acid for superficial keratinocytic neoplasms

BACKGROUND: Photodynamic therapy (PDT) is a treatment technique in which photosensitizing substances are applied in tissues and excited with specific wavelengths of light energy to obtain cell destruction through photoactive cytotoxic substances. This method has been used in several skin neoplasms, with quite successful results. OBJECTIVES: To study the effects of one single session of topical delta-aminolevulinic acid (ALA) irradiated with incoherent light, in actinic keratosis (AK), superficial basal cell carcinoma (BCC) and Bowen's disease (BD). PATIENT AND METHODS: Eighty skin lesions, in 52 patients, were treated with an incoherent light source prototype built by the Service of Biomedical Engineering of Hospital de Clínicas de Porto Alegre (HCPA), after the application of 20% ALA under occlusion. Thirty two (40%) were superficial BCC, 37 (46.3%) AK, and 11 (13.7%) BD. Diagnosis was confirmed by biopsy and histology in 23 cases (28.7%). RESULTS: Follow up was not available in five lesions. From the remaining 75, 41 (54.6%) were completely resolved, 22 (29.4%) showed partial remission, and 12 (16.0%) were considered as treatment failures. Considering the 35 treated AK, 23 (65.7%) presented complete response, 7 (20%) improved, and 5 (14.3%) showed no benefit after treatment. Thirty BCC were treated, 10 (33.3%) completely resolved, 13 (43.4%) improved, and 7 (23.3%) remained unaffected. From 10 treated BD, 8 (80%) resolved and 2 (20%) improved. Observed side effects were burning sensation in 24 lesions (32%), pain in 5 (6.7%), and itch in one case (1.3%). Most patients (60%) did not experience any important side effects. CONCLUSION: The results of this study are similar, in part, to the results of other studies present in the literature that used a single treatment with ALA/PDT for superficial keratinocytic neoplasms, especially for actinic keratosis and Bowen's disease.

carcinoma; basal cell; Bowen's disease; photobiology; photochemotherapy

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