Acta Dermato-Venereologica 99-10CompleteContent | Page 12

884 CLINICAL REPORT Effectiveness of 5% Topical Imiquimod for Lentigo Maligna Treatment Darryl C. K. S. TIO 1 , Catherine VAN MONTFRANS 2 , Claire G. H. RUIJTER 1 , Rick HOEKZEMA 1 and Marcel W. BEKKENK 1 1 Department of Dermatology, Amsterdam University Medical Centers, Vrije Universiteit Medical Centre, Amsterdam, and 2 Department of Dermatology, Erasmus Medical Centre, Rotterdam, The Netherlands Lentigo maligna (LM) is treated to prevent progres- sion to lentigo maligna melanoma (LMM). Surgery is the gold standard, but an alternative treatment is off- label topical imiquimod. The aim of this study was to evaluate the effectiveness of 5% topical imiquimod treat­ment for lentigo maligna. In the period 2007– 2017 57 patients with lentigo maligna were trea­ ted with off-label topical imiquimod once daily for 12 weeks. Complete clinical clearance was observed in 48 patients (84.2%) and partial clearance in 3 patients (5.3%). Three patients (5.3%) showed no response and another 3 patients (5.3%) stopped treatment due to side-effects. After 4.5 years, during follow-up, one patient developed a lentigo maligna melanoma, which was subsequently excised. Treatment with topical imiquimod resulted in complete clearance of lentigo maligna in 48 out of 57 patients (84.2%). Topical imi- quimod is an acceptable treatment option for patients with lentigo maligna who prefer topical treatment to surgery or radiotherapy. Key words: lentigo maligna; topical imiquimod; melanoma. Accepted Jun 18, 2019; E-published Jun 24, 2019 Acta Derm Venereol 2019; 99: 884–888. Corr: Darryl Tio, Department of Dermatology, Amsterdam University Medical Centers, Vrije Universiteit Medical Centre, De Boelelaan 1117, 1081HV Amsterdam, The Netherlands. E-mail: [email protected] L entigo maligna (LM) is considered a type of me- lanoma in situ. It is prevalent in a predominantly elderly population with a fair skin type. LM typically occurs on chronic sun-exposed skin, such as the head and neck area, where critical anatomical structures are located. Elderly patients often have multiple comorbi- dities and, as a consequence, clinical management may be challenging. Several studies have shown an increased incidence of LM over recent decades (0.54 LM/100,000 patient years to 1.99 LM/100,000 patient years) (1–4). Treatment of LM is recommended in order to prevent progression to lentigo maligna melanoma (LMM), which can metastasize. The true progression rate is unknown, but a recent epidemiological study describing 10,545 LM and 124 LMM patients reported that the cumulative risk of LMM developing after a LM on any location after 25 years is 2.0–2.6%. The progression of individual lesions could not be evaluated in this study (1). According to the current European Consensus Gui- deline (5), surgical excision is the gold standard for doi: 10.2340/00015555-3241 Acta Derm Venereol 2019; 99: 884–888 SIGNIFICANCE Lentigo maligna is treated to prevent progression to lentigo maligna melanoma. The current treatment of choice for len- tigo maligna is surgical excision. Topical imiquimod is an al- ternative option. In this study, topical imiquimod treatment was successful in 84.2% of patients with lentigo maligna. treatment of LM. Alternative treatment options, such as off-label topical imiquimod 5%, radiotherapy, or watch- ful waiting, are mentioned in the guideline, but there is no recommendation on their application (5). Surgical excision of larger lesions can result in disfiguring scars or functional impairment, and radiotherapy could poten- tially cause secondary malignancies or radiodermatitis (6, 7). Off-label topical imiquimod has the advantage of providing a good cosmetic outcome and it is easy to use for elderly patients (8). The reported response rate to off-label topical imiqui- mod for LM varies between 37.0% and 78.6% (9–12). This wide range of response rates could be due to the use of different treatment regimens. A survey performed by our group among 415 derma- tologists in Europe showed that non-surgical options are used quite often. Of the respondents, 17.0% indicated that they use radiotherapy, 30.6% topical imiquimod, and 19.6% watchful waiting when treating LM patients >70 years of age (13). Patients with LM have been treated with off-label topical imiquimod 5% since 2007. The patients recrui- ted for this cohort between 2007 and 2012 have been described previously by Kirtschig et al. (8), who treated 27 patients with topical imiquimod, of whom 20 (74%) showed complete clinical and histological clearance with a mean follow-up of 39 months. The current study expands this cohort with 30 additional patients with LM treated between 2012 and 2017. The aim of this study was to analyse all patients with LM treated prospectively with off-label topical imiquimod at our centre between November 2007 and December 2017, in order to evaluate the effectiveness of this treatment. Data were collected retrospectively by reviewing clinical records. METHODS Patients were usually referred to our academic referral centre when they were not eligible for surgical treatment or did not want This is an open access article under the CC BY-NC license. www.medicaljournals.se/acta Journal Compilation © 2019 Acta Dermato-Venereologica.