Efficacy of imiquimod as an adjunct to cryotherapy for actinic keratoses

Abstract

Background: Cryotherapy is the standard of care for clinically apparent (target) actinic keratoses (AKs). Topical imiquimod may reduce initially inapparent or subclinical AKs.

Objective: We evaluated the potential of topical imiquimod to decrease subclinical AKs after cryotherapy of target AKs.

Methods: A randomized trial of imiquimod or vehicle twice weekly for 8 weeks following 3- to 5-second cryotherapy of target AKs within a 50 cm(2) field at the face or scalp was conducted. Efficacy outcomes included clearance of target, subclinical, and total AKs and proportions clear of AKs. Subjects with residual AKs were offered cryotherapy and open-label imiquimod twice weekly for 8 weeks.

Results: Sixty-three subjects completed the randomized phase. At 12 weeks, target AK clearance was similar for imiquimod and vehicle (79% vs 76%), but fewer total AKs were noted for imiquimod (78 vs 116). This was due to a progressive reduction in subclinical AKs with imiquimod compared with a progressive increase with vehicle. More subjects treated with imiquimod achieved clearance of subclinical (58% vs 34%; p = .06) and total (23% vs 9%; p = .21) AKs.

Conclusion: Imiquimod postcryotherapy may increase clearance of subclinical and total AKs and proportions of subjects clear at 3 months. These findings require confirmation in larger controlled trials powered for statistical significance.