Topical Photodynamic Therapy with Methyl-aminolevulinic Acid for the Treatment of Actinic Keratosis

Park, Hyun Sun; Jin, Seon Pil; Cho, Kwang Hyun

Abstract

BACKGROUND
Photodynamic therapy (PDT) is a treatment modality involving the use of a photosensitizer, oxygen and a light source to induce selective targeted cell death. It is used for various skin conditions, including actinic keratosis (AK). Both 5-aminolevulinic acid and methyl aminolevulinic acid (MAL) are currently available as photosensitizers. Although there are several studies on the treatment of AK using 5-aminolevulinic acid-PDT in Korea, there are few studies on using MAL-PDT for the treatment of AK.
OBJECTIVE
The purpose of this study is to evaluate the efficacy and safety of MAL-PDT for the treatment of AK.
METHODS
We performed a retrospective study and reviewed 64 AK lesions from 28 patients who were treated by MAL-PDT between January 2008 and April 2010. The data was collected through the medical records, the clinical photographs and the biopsy specimens.
RESULTS
The patients were treated with either a single treatment or double treatments 1 week apart. The treatment results were assessed after 12 weeks. Overall, complete remission was achieved in 42/64 lesions (65.6%). Although a single treatment was effective for thin lesions, the complete response rates were significantly lower for the moderately thick and severely thick lesions (100% vs 71.3% vs 22.2%, respectively). Repeated treatment tended to improve the complete response rate of the severely thick lesions. A favorable cosmetic outcome was achieved and only tolerable local side effects were reported after MAL-PDT. The patients were followed up for an average period of 6 months and 4 lesions recurred.
CONCLUSION
MAL-PDT is an effective and well-tolerated treatment option for thin and moderately thick AK. However, further study is required for determining the optimal regimen for thicker lesions and the long-term treatment results of MAL-PDT.