A novel two-stage treatment of lentigo maligna using ablative laser therapy followed by imiquimod

Funding sources: no external funding. Conflicts of interest: none declared. Madam, Lentigo maligna (LM) is a slowly growing premalignant skin cancer, typically arising in sun‐exposed skin in elderly individuals. The lifetime risk of LM progressing to LM melanoma varies from 2·2 to 4·7%.1 The first treatment of choice for LM is wide local excision with a margin of at least 5 mm, which leads to clearance rates of about 24–70% and recurrence rates of 7–20%.2 Staged surgical excision is associated with recurrence rates of 0–9·7%, with mean follow‐up periods of 4·7–96 months.2 In some patients, surgical treatment will inevitably lead to large skin defects and complex surgical reconstructions. Several alternative treatment modalities have been used, including topical imiquimod, laser therapy, radiation therapy and cryosurgery.2 Here we describe a novel treatment modality, whereby ablative laser therapy is followed by topical applications of imiquimod 5% cream for 6 weeks. From 2008 until 2011, 12 patients with histologically proven LM on the face who refused surgery were treated using a combination of ablative laser therapy and topical imiquimod 5% cream. The entire epidermis and the superficial papillary dermis of the LM lesion was vaporized after repeated passes using an Er : YAG laser. The endpoints of laser treatment were complete pigment clearance and the occurrence of punctuate bleeding. A margin of at least 2 cm of adjacent skin was also ablated. Patients started imiquimod application on the treated area the next day and continued once daily for 5 consecutive days per week, for a total of 6 weeks. The occurrence of an inflammatory reaction was assessed by two clinicians. The follow‐up for clinical evaluation (by W.H. or K.V. and E.P.) and signs of recurrence consisted of visits at 1, 3 and 6 weeks after laser treatment, and every 6 months thereafter. Dermoscopy was not performed. Patient characteristics are shown in Table 1.