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

Background: Surgical resection of lentigo maligna (LM) is complicated by noncontiguous, subclinical extension and actinic melanocytic hyperplasia in sun-damaged skin of older individuals.

Objective: We sought to determine the long-term effectiveness of imiquimod as primary or adjuvant therapy for LM.

Methods: Patients were retrospectively identified from January 1, 2003, to December 31, 2013, with LM, early/evolving LM, and LM melanoma who had used topical imiquimod 5% cream for either primary therapy after diagnostic biopsy, or adjuvant therapy after narrow-margin surgical resection or complete clinical but not histologic resection of LM. Follow-up occurred through December 31, 2014.

Results: In all, 63 cases were identified in 61 patients, mean (SD) age 71.1 (12.4) years; 58 were analyzed for local recurrence. Imiquimod was used as primary therapy in 22 of 63 (34.9%) and adjuvant therapy in 41 of 63 (65.1%) for mean duration of 11.7 (range 2-60) weeks. Fifty cases (86.2%) demonstrated clinical clearance at mean (SD) follow-up of 42.1 (27.4) months: 72.7% primary and 94.4% adjuvant at 39.7 (23.9) and 43.1 (28.9) months, respectively.

Limitations: Retrospective cohort study and lack of standardized imiquimod application are limitations.

Conclusion: Imiquimod cream appears to be a viable option for primary or adjuvant treatment of LM in older patients who are poor surgical candidates.