Imiquimod Cream May Be Effective In Primary And Adjuvant Treatment Of Lentigo Maligna

Susan Swetter, MD Professor of Dermatology and Director, Pigmented Lesion and Melanoma Program Stanford University Medical Center and Cancer Institute.MedicalResearch.com Interview with:
Susan Swetter, MD

Professor of Dermatology and Director, Pigmented Lesion and Melanoma Program
Stanford University Medical Center and Cancer Institute.

 

Medical Research: What is the background for this study?

Dr. Swetter: This retrospective cohort study sought to explore the role of the topical immunomodular – imiquimod 5% cream – as both primary and adjuvant therapy (following optimal surgery) for patients with the lentigo maligna subtype of melanoma in situ. Assessment of alternative treatments to surgery for this melanoma in situ subtype are warranted given the increasing incidence of lentigo maligna in older, fair-complexioned individuals in the United States. Surgical management of lentigo maligna is complicated by its location on cosmetically sensitive areas such as the face, histologic differentiation between lentigo maligna and actinic melanocytic hyperplasia in chronically sun-damaged skin, and potential surgical complications in the elderly who may have medical co-morbid conditions.

Medical Research: What are the main findings?

Dr. Swetter: We conducted a retrospective review of 63 cases of lentigo maligna in 61 patients (mean age 71.1 years) who used topical 5% imiquimod cream instead of surgery (22 of 63 cases, 34.9%) or as an adjuvant therapy following attempted complete excision (63 cases, 65.1%), in which no clinical residual tumor was present but the histologic margins were transected or deemed narrowly excised. Our study showed overall clinical clearance of 86.2% in the 58 patients analyzed for local recurrence at a mean of 42.1 months of follow-up (standard deviation 27.4 months), with primarily treated cases demonstrating 72.7% clearance at a mean of 39.7 months (standard deviation 23.9 months), and adjuvant cases showing 94.4% clearance at a mean of 39.7 months (standard deviation 23.9 months).  We found a statistically significant association between imiquimod-induced inflammation and clinical or histologic clearance in primary but not adjuvant cases, although this latter finding may be explained by a lack of residual atypical melanocytes or true LM in the adjuvant setting, in which wide local excision had already been performed.

Medical Research: What should clinicians and patients take away from your report?

Dr. Swetter: While our study is not a prospective clinical trial assessing the use of imiquimod cream in the treatment of lentigo maligna, it adds to the body of published data demonstrating efficacy of this topical agent in both the primary and adjuvant settings. Current National Comprehensive Cancer Network and American Academy of Dermatology Guidelines recommend surgical excision of lentigo maligna when possible, but also recognize the role of alternative therapies in cases where surgery has been optimized or is not possible. The use of topical imiquimod for melanoma in situ, lentigo maligna type, remains “off-label” (non-FDA-approved), and a thorough discussion with the patient/family must occur regarding potential risks, benefits, and limitations of topical therapy in place of, or as an adjunct to surgery. Imiquimod field therapy requires close clinical surveillance and patient compliance with treatment and follow-up.

Medical Research: What recommendations do you have for future research as a result of this study?

Dr. Swetter: A multi-center, randomized controlled prospective trial should be conducted to determine the long term efficacy of topical imiquimod compared with or as an adjunct to surgical resection of lentigo maligna. Given the high and increasing rates of the lentigo subtype in older individuals, further study of this topical field treatment is warranted.

Citation:

Imiquimod 5% cream as primary or adjuvant therapy for melanoma in situ, lentigo maligna type

Susan M. Swetter, MD, Frank W. Chen, MD David D. Kim, BA, Barbara M. Egbert, MD

DOI: http://dx.doi.org/10.1016/j.jaad.2015.02.008

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MedicalResearch.com Interview with: Susan Swetter, MD (2015). Imiquimod Cream May Be Effective In Primary And Adjuvant Treatment Of Lentigo Maligna