An algorithm for the management of residual head and neck melanoma in situ using topical imiquimod
Amanda Norwich, MD, Cynthia Tsay, BS, Samuel Kim, MD, Deepak Narayan, MD.
Yale University, NEW HAVEN, CT, USA.
Melanoma in situ (MIS) is an early variant of melanoma in which the disease is limited to the epidermis. Standard therapy is currently surgical excision with 5mm margins. In some instances, there are large or difficultly placed lesions where complete excision will result in aesthetic or functional impairment. We propose treatment of positive margins with topical imiquimod and will propose an algorithm in the following paper.
Our inclusion criteria were patients undergoing surgical excision of MIS with residual disease or positive margins. Patients applied 5% imiquimod 3-5 times per week for at least 6 weeks at the site of the positive margin(s). Duration and frequency of treatment was titrated based on response observed. A re-excision skin biopsy using 1 mm margins was performed after residual inflammation subsided. Our endpoints were recurrence and effectiveness with length of treatment.
Sixteen patients met our criteria. Twelve lesions were classified as MIS in the initial biopsy; the remaining four were either melanoma stage T1A or T1B. Mean follow-up time was 14.3 months. We had three patients without response and of these, two recurred with either atypical SCC or MIS. Cure rate following use of topical imiquimod, excluding the patient lost to follow up, was 87%.
The proposed algorithm for the treatment of residual disease in head and neck melanoma and MIS using topical imiquimod offers various advantages. This anatomical region is cosmetically sensitive, and the option of using 1 mm re-excision margins after imiquimod treatment yields comparable cure rates with less tissue excised overall. Imiquimod treatment eliminates the need for medical follow-up with a plastic surgeon and allows the medical oncologist or dermatologist to assume primary responsibility for the
individual. Finally, our reported algorithm demonstrates that at least six weeks of active inflammation provides comparable results to the traditional twelve-week course. Therefore, patients receive the benefit of a comparable outcome with shorter treatment times. This decreased treatment time would reduce patient discomfort and improve adherence to therapy. The algorithm also allows for excision of the narrower margins (ie. 1mm vs 5mm) with the accompanying benefits of cosmesis and oncologic clearance.
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