Objective: To determine if the complete response rates of lentigo maligna (LM) to imiquimod, 5%, cream can be improved by the addition of a topical retinoid.
Design: Prospective randomized study of patients treated with imiquimod alone vs imiquimod plus a topical retinoid, followed by conservative staged excisions.
Setting: Mohs surgical clinic in an academic institution.
Patients: Ninety patients with biopsy-confirmed LM.
Interventions: Ninety patients with 91 LMs were randomized into 2 groups. One group received imiquimod, 5%, cream 5 d/wk for 3 months, while the other group also received tazarotene, 0.1%, gel 2 d/wk for 3 months. Following topical therapy, all patients underwent staged excisions and frozen section analysis with Melan-A immunostaining to confirm negative margins.
Main outcome measure: The presence or absence of residual LM at the time of staged excision.
Results: Forty-six patients with 47 LMs were randomized to receive monotherapy: 42 of 47 LMs reached the intended treatment duration, with 27 complete responses (64%). Forty-four patients with 44 LMs were randomized to receive combined therapy: 37 of 44 LMs reached the intended treatment duration, with 29 complete responses (78%). This difference did not reach statistical significance (P=.17). There have been no recurrences to date, with a mean follow-up period of 42 months.
Conclusions: Among patients who received topical imiquimod with vs without tazarotene, 22% (8 of 37) of lesions vs 36% (15 of 42) of lesions showed residual LM on staged excisions. Pretreating LM with imiquimod, 5%, cream may decrease surgical defect sizes; however, total reliance on topical imiquimod as an alternative to surgery may put the patient at increased risk of a local recurrence.
Trial registration: ClinicalTrials.gov NCT00707174.