Aminolevulinic acid and methyl aminolevulinate equally effective in topical photodynamic therapy for non-melanoma skin cancers

Abstract

Background: Topical photodynamic therapy (PDT) is an effective treatment for superficial non-melanoma skin cancers. Two prodrugs, 5-aminolevulinic acid (ALA) and methyl aminolevulinate (MAL), are available for clinical use. There is, however, a lack of studies comparing the clinical effectiveness of these two prodrugs.

Objective: The objective of the study was to compare the clinical response between ALA- and MAL-PDT when treating actinic keratosis (AK), Bowen's disease (BD), nodular basal cell carcinoma (nBCC) and superficial basal cell carcinoma (sBCC).

Methods: During the period 2002-2009, patients with AK, BD, nBCC and sBCC were treated with ALA- and MAL-PDT at the Department of Dermatology at Karlskoga Hospital in Sweden using a fixed protocol. All patients were followed up approximately 6 months after treatment to evaluate the clinical results, which were analysed retrospectively.

Results: In total, 116 patients with 203 tumours were treated with PDT during the study period. ALA- and MAL-PDT were used for 24 vs. 44 AK fields, 9 vs. 18 BD lesions, 19 vs. 25 nBCCs and 25 vs. 39 sBCCs. Response rates with ALA- and MAL-PDT, respectively, were 63% and 75% for AK, 89% and 78% for BD, 84% and 84% for nBCC and 88% and 87% for sBCC. There were no statistically significant differences in the complete clinical response rates for ALA- and MAL-PDT when used for any of the four lesion types.

Conclusion: ALA- and MAL-PDT appear to be equally effective in the treatment of AK, BD, nBCC and sBCC. Nevertheless, larger, prospective, randomized and controlled studies should be carried out to confirm these results.