Cutaneous squamous cell carcinoma progression during imiquimod treatment

To the Editor: We read with interest the paper by Que SKT et al regarding the management of cutaneous squamous cell carcinoma (cSCC)1 and the remarkable discussion about the field treatment with topical chemotherapy agents. Imiquimod is an immune response modifier that activates immune cells via toll-like receptor 7, initiating a cascade leading to the induction of cytokines, such as interferon alfa, interferon gamma, and interleukin 12, which promote a T helper 1 (TH1) immune response.2 The use of imiquimod for the treatment of invasive cSCC is not approved by the European Medicines Agency or Food and Drug Administration, but few reports have described its success in elderly patients and when other treatments and surgery are contraindicated.