Imiquimod 5% cream monotherapy for cutaneous squamous cell carcinoma in situ (Bowen's disease): A randomized, double-blind, placebo-controlled trial

Background: We conducted a double-blind, placebo-controlled, randomized trial to evaluate the preliminary efficacy and safety of imiquimod 5% cream treatment for cutaneous squamous cell carcinoma (SCC) in situ. Methods: In all, 31 patients with biopsy-proven cutaneous SCC in situ were randomly assigned to placebo (vehicle) (n = 16) or imiquimod 5% cream (n = 15) daily for 16 weeks. Patients were assessed at week 28 for the primary end point, resolution of cutaneous SCC in situ. Results: Of the 31 patients enrolled, 3 dropped out. Intention-to-treat analysis revealed 11 of the 15 patients (73%) in the imiquimod group achieved resolution of cutaneous SCC in situ, with no relapse during the 9-month follow-up period; none in the placebo group achieved resolution (P <.001). Imiquimod 5% cream was generally well tolerated and there were no serious adverse events. Limitations: Topical imiquimod 5% cream has proven to he an effective treatment for cutaneous SCC in situ. However. studies to define the ideal closing regimen and cost-effectiveness are required before it can be accepted as a recognized therapy. Conclusions: in this controlled trial, patients with cutaneous SCC in situ receiving topical imiquimod 5% cream as monotherapy experienced a high degree of clinical benefit compared with placebo.