Evaluating the response of imiquimod therapy for actinic keratoses

Abstract

Currently, an evaluation of imiquimod therapy (IT) response against actinic keratosis (AK) includes only ocular inspection. The therapy is deemed effective when the skin manifestations disappear. Following IT, the lesions usually leave behind some amount of erythema. Observational data were compared with histopathology findings of biopsies taken before and after IT from 15 patients with AK. Since all of 9 lesions clinically judged as marked relief and one out of four lesions judged as slight relief had histologically no tumor cells, they should be included in disappearance group. The ineffective 3 patients showed reduced skin findings with absence of tumor cells in the follow-up period, which was regarded as the late effect of IT. Finally 93.3% of the cases were judged effective. Though the time of evaluation should be 8 weeks after final imiquimod application routinely, some cases should be judged at later time point with histological confirmation. [Skin Cancer (Japan) 2016 ; 31 : 238-243]