The clinical efficacy of topical methyl-aminolevulinate photodynamic therapy in moderate to severe actinic keratoses of the face and scalp

Introduction: Since actinic keratoses (AKs) often appear in areas with field cancerization, photodynamic therapy (PDT) may have significant advantages over the standard treatment options. Objectives: Clinical efficacy of PDT with topical methyl aminolevulinate (MAL-PDT) in field cancerization was evaluated with respect to the number of AKs and photodamage. Methods: A total of 14 patients with 223 AKs on the face or scalp were treated with MAL-PDT. Two treatments with a 3-monthly interval were given. At baseline, before the second treatment and 3 months after the end of therapy, the number of AKs were counted and photodamage was assessed with respect to skin roughness, hyperpigmentation, hypo-pigmentation, scarring, atrophy, telangiectasia and wrinkling. Results: Complete clearance was reached in patients with a moderate degree of actinic damage, whereas a severe degree of field cancerization demonstrated only partial clearance. The global score for photodamage improved significantly. After the follow-up period, none of the patients reaching clearance had developed relapsing or new AKs. Conclusions: MAL-PDT induces a high clearance rate of AKs, dependent on the degree of field cancerization, with a good improvement in photodamage and prevention of developing new AKs. Thus, more PDT sessions are needed in patients with a severe degree of field cancerization.