Imiquimod for the treatment of Bowen's disease and invasive squamous cell carcinoma.

Topical imiquimod is an immune response modifier FDA approved for the treatment of anogenital warts. Recent studies have reported its effectiveness in the treatment of some types of basal cell carcinomas. There have also been some case reports and case series reporting success treating of squamous cell carcinoma in situ with imiquimod. We report two patients with squamous cell carcinoma in situ and one with invasive squamous cell carcinoma treated with 5% imiquimod cream. Lesions were located on shin, posterior shoulder, and nasal tip. 5% imiquimod cream was applied at night for six weeks. Side effects included erythema and crusting in one patient. Biopsies taken four weeks after treatment revealed no residual squamous cell carcinoma in situ or squamous cell carcinoma. Topical 5% imiquimod cream is becoming established as a promising treatment for squamous cell carcinoma in situ. It also seems to be an alternative treatment for some cases of squamous cell carcinoma.