Comparative study for the effect of photodynamic therapy, imiquimod immunotherapy and combination of both therapies on 40 lesions of actinic keratosis in Japanese patients.

We treated 12, 15 and 13 Japanese actinic keratosis (AK) lesions with 5-aminolevulinic acid photodynamic therapy (PDT), 5% imiquimod cream and combination of both therapies, respectively, and compared the effects. Patients underwent the second course, when AK lesions remained after the first course. Efficacy was evaluated 1 month after each treatment. Combination therapy cleared all AK lesions only after the first course, while PDT and imiquimod therapy cleared 41.7% and 66.7% of AK lesions after the first course, respectively. All residual AK lesions after the first course were cleared by the second courses of PDT or imiquimod therapy. During the course, erosion and crust developed significantly more frequently in combination therapy (P < 0.001). Most Japanese AK lesions can be satisfactorily treated with either PDT or imiquimod monotherapy. However, only severe cases may better be treated with combination therapy, which show higher efficacy even though adverse events occur frequently.