Background: Actinic keratosis (AK) is a very common condition, which has the potential of progressing to squamous cell carcinoma. The present study is a prospective, randomized study comparing the lesion response, cosmetic outcome, patient satisfaction and tolerability of a new treatment modality, photodynamic therapy (PDT), using topical methyl aminolevulinate (Metvix), with the most commonly used standard therapy for AK, cryotherapy.
Methods: A total of 204 patients with clinically diagnosed AK were randomized to either cryotherapy or PDT. The PDT patients were further assigned to an active or placebo group in a random, double-blind manner. Cryotherapy was performed using liquid nitrogen spray in a single freeze-thaw cycle. PDT was performed using 160 mg/g methyl aminolevulinate cream or placebo, a 3-hour application time, red light (570-670 nm) and a total light dose of 75 J/cm(2). PDT was repeated after 7 days. Two sessions of PDT were undertaken, as a previous study had shown a single session had similar efficacy to cryotherapy. Lesion response was assessed clinically after 3 months (complete response or non-complete response).
Results: The lesion response rate was 91% in the methyl aminolevulinate PDT group, 68% in the cryotherapy group and 30% in the placebo PDT group. Methyl aminolevulinate PDT was statistically significantly better than both cryotherapy and placebo PDT in terms of response rates and cosmetic outcome. Most patients preferred PDT to other treatments.
Conclusions: PDT with methyl aminolevulinate is an excellent treatment option, particularly for patients with widespread damage or AK lesions in cosmetically sensitive areas.