Assessing the Efficacy of Imiquimod Use in Patients With Persistent Locally Advanced Melanoma In Situ

May 2023 | Volume 22 | Issue 5 | 457 | Copyright © May 2023


Published online April 24, 2023

doi:10.36849/JDD.6987 Ward C, DePalo D, Patel N, et al. Assessing the efficacy of imiquimod use in patients with persistent locally advanced melanoma in situ. J Drugs Dermatol. 2023;22(5):457-464. doi:10.36849/JDD.6987

Caroline Ward BAa*, Danielle K. DePalo MDb*, Nupur Patel MDc, Michael Carr MDb, Brian Longbottom BSa, Kathleen Cunningham PA-Cb, Ashley Culbreth PA-Cb, Rhianna Reed PA-Cb, Andrea Harkins PA-Cb, Chris Puleo PA-Cb, Lilia Correa MDb,c, Lucia Seminario-Vidal MD PhDb,c,d, Jonathan S. Zager MD FACSb,d

aUniversity of South Florida Morsani College of Medicine, Tampa, FL
bDepartment of Cutaneous Oncology, Moffitt Cancer Center, Tampa, FL
cDepartment of Dermatology, University of South Florida Morsani College of Medicine, Tampa, FL
dDepartment of Oncologic Sciences, University of South Florida Morsani College of Medicine, Tampa, FL

*Co-first authors

Abstract
Background: The standard of care when treating melanoma in situ (MMIS) is an excision with at least 5 mm surgical margins.1 Some studies have suggested up to 9 mm margins to maximize local recurrence-free survival.2 This retrospective review aims to assess the efficacy of imiquimod as a topical treatment for persistently positive MMIS at the margins of prior excisions or where surgery is not an option.
Methods: Retrospective study conducted at Moffitt Cancer Center between 2019 and 2021 with patients aged > 18 years with MMIS at the margins of excision of an invasive melanoma or MMIS. Included patients were not ideal candidates for primary or additional surgical resection due to non-feasibility of surgery because of comorbidity or cosmetically sensitive location and/or the need for repeated skin grafting, or due to patient's refusal. Patients received imiquimod on protocol for 16 weeks and were monitored for treatment response and side effects. Following completion of the treatment, scouting biopsies were performed to assess histological response, and dermoscopy was used to determine the clinical disease status.
Results: Ten patients completed 16 weeks of imiquimod. Seven (75%) had a median of 2 surgical resections, and 3 refused surgery despite discussion that surgery was standard of care. Seven were deemed free of disease on post-imiquimod treatment scouting biopsies, while 2 were found to be clinically free of disease following confocal microscopy, indicating a tumor clearance rate of 90% with imiquimod treatment. One patient was found to have persistent residual disease following 2 rounds of imiquimod and was taken for an additional surgical excision after which they were deemed free of disease. Median follow-up duration from the onset of imiquimod therapy to the last clinic visit was 18 months, without any recurrences to date.
Conclusion: Imiquimod appears to demonstrate an encouraging tumor clearance among patients with persistent MMIS after surgery where further surgical resection may not be feasible. Although long-term durability has not been demonstrated in this study, a 90% tumor clearance rate is promising.

J Drugs Dermatol. 2023;22(5): doi:10.36849/JDD.6987

Ward C, DePalo D, Patel N, et al. Assessing the efficacy of imiquimod use in patients with persistent locally advanced melanoma in situ. J Drugs Dermatol. 2023;22(5):457-464. doi:10.36849/JDD.6987

INTRODUCTION

Melanoma in situ (MMIS) is a prominent stage of melanoma, defined as noninvasive and confined to the epidermis. In the United States, there are approximately 207,000 new melanoma cases each year, with MMIS accounting for nearly 101,000 of these cases.3 According to Higgins et al, the incidence of MMIS has risen rapidly over the past 3 decades, especially among younger patients between 20 and 49-years old.4 The rise in incidence for MMIS is thought to be due to more frequent and vigilant screening efforts, especially among the younger population, as well as increased scrutiny of biopsy specimens among dermatopathologists.5 The most common site for MMIS involvement is the head and neck region, as these areas are prone to greater sun damage, followed by the trunk, upper, and lower extremities.4

The NCCN guidelines define the standard of care as a wide excision surgical technique with 5 mm margins for MMIS and 1 to 2 cm margins when invasive melanoma is present within the biopsy specimen.1 Kunishige et al demonstrated that surgical margins between 6 mm and 9 mm achieve the highest percent clearance of MMIS, with respective values of 86% and 98.9%.2 Positive margins after initial surgical resection pose a greater
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