Efficacy of imiquimod in the management of lentigo maligna

J Eur Acad Dermatol Venereol. 2023 Sep;37(9):1785-1791. doi: 10.1111/jdv.19141. Epub 2023 May 6.


Background: Lentigo maligna (LM) is a melanocytic proliferation occurring on photo-exposed skin that may progress to LM melanoma. Surgery is recommended as first-line treatment. Excision margins of 5-10 mm remain, without international consensus. Several studies have shown that imiquimod, an immunomodulator, induces LM regression. This study investigated the effect of imiquimod versus placebo in neoadjuvant settings.

Patients and methods: We performed a prospective, randomized, multicentre, phase III clinical study. Patients were randomly assigned in 1:1 ratio to receive imiquimod or placebo for 4 weeks, followed by LM excision 4 weeks after the last application of imiquimod or placebo. The primary endpoint was extra-lesional excision, with a 5 mm margin from the residual pigmentation after imiquimod or vehicle. Secondary endpoints included the gain on the surface removed between the two groups; number of revision surgeries to obtain extra-lesional excisions; relapse-free time; and number of complete remissions after treatment.

Results: A total of 283 patients participated in this study; 247 patients, 121 patients in the placebo group and 126 in the imiquimod group, accounted for the modified ITT population. The first extralesional extirpation was performed in 116 (92%) imiquimod patients and in 102 (84%) placebo patients; the difference was not significant (p = 0.0743). Regarding the surface of LM, imiquimod reduced the LM surface (4.6-3.1 cm2 ) significantly (p < 0.001) more compared to the placebo (3.9-4.1 cm2 ).

Conclusion: Imiquimod reduces the lentigo maligna surface after 1 month of treatment, without a higher risk of intralesional excision and with a positive aesthetic outcome.

Publication types

  • Randomized Controlled Trial
  • Multicenter Study
  • Clinical Trial, Phase III

MeSH terms

  • Aminoquinolines / therapeutic use
  • Antineoplastic Agents* / therapeutic use
  • Humans
  • Hutchinson's Melanotic Freckle* / drug therapy
  • Hutchinson's Melanotic Freckle* / surgery
  • Imiquimod / therapeutic use
  • Neoplasm Recurrence, Local / drug therapy
  • Prospective Studies
  • Skin Neoplasms* / drug therapy
  • Skin Neoplasms* / surgery


  • Imiquimod
  • Antineoplastic Agents
  • Aminoquinolines

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