There is some debate regarding the rate of progression of
actinic keratosis (AK) into
squamous cell carcinoma (SCC).1-4 However, it is clear that treatment for AK lesions is warranted. Results from numerous studies with
aminolevulinic acid (ALA) and methyl aminolevulinate (MAL)
photodynamic therapy (
PDT) for the treatment of AKs, SCC, and
Bowen's disease show high rates of clearance for these lesions. MAL/
PDT provides similar efficacy to ALA/
PDT with the benefits of shorter incubation times according to the approved FDA labeling, greater selectivity, reduced
pain during and immediately following
therapy, and fewer systemic side effects. Cosmetic outcomes are better with
PDT than with
cryosurgery or excisional surgery. A number of case reports show efficacy with ALA/
PDT and MAL/
PDT for
acne, photorejuvenation, and other off-label indications. Side effects with
PDT tend to be mild to moderate and transient in nature. Overall, ALA/
PDT and MAL/
PDT are effective for a variety of
skin diseases and conditions. MAL/
PDT provides some advantages over ALA/
PDT.