An Algorithm for the Management of Residual Head and Neck Melanoma In Situ Using Topical Imiquimod: A Pilot Study

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 at least 5-mm margins. In some instances, there are large or anatomically difficult lesions where complete excision will result in significant esthetic or functional impairment. Our experience has shown a 6-week course to be sufficient in certain patients compared with the suggested 12-week course. In this context, we propose a shortened duration of treatment of positive margins with topical imiquimod and propose an algorithm that results in the least amount of dysfunction for the patient.

Our inclusion criteria were patients undergoing excision of a lesion found to have postsurgical margins, which were positive for MIS. Patients applied 5% imiquimod 3 to 5 times per week for at least 6 weeks at the site of the positive margin(s). Duration and frequency of treatment were titrated based on response. A reexcision 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. All patients were found to have MIS in the margins after surgical excision. Twelve of those lesions were classified as MIS in the initial biopsy; the remaining 4 were either melanoma stage T1A or T1B. Mean follow-up time was 14.3 months, and 1 patient was lost to follow-up. We had 3 patients without response, and of these, 1 was found to have atypical squamous cell carcinoma and the other had a recurrence of MIS. Cure rate after use of topical imiquimod was 93.3% (14/15).

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 versus 5 mm reexcision margins after imiquimod treatment yields comparable cure rates with less tissue excised overall. Our algorithm demonstrates that 6 weeks of active inflammation provides comparable results with the traditional 12-week course. This decreased treatment time reduces patient discomfort and improves patient adherence.