The paradigm shift in treating actinic keratosis: a comprehensive strategy.

Actinic keratoses (AKs) are cutaneous areas of atypical squamous transformation that are considered to be an early step in the continuum of transformation from normal skin to invasive and metastatic cutaneous squamous cell carcinoma (SCC). Enhanced understanding of the pathophysiologic changes leading from AK to malignancy, combined with an increasing global prevalence of AK, has led to a new focus on the importance of combining local treatments that remove individual lesions with topical or procedural field therapies that treat the entire actinically damaged field--also known as field cancerization--which is important because it is impossible to predict which AK lesions will progress to SCC. Currently available topical field therapies include 5 fluorouracil cream (5%, 1%, 0.5%), imiquimod cream (5% and 3.75%), diclofenac sodium gel 3% with 2.5% hyaluronic gel, and ingenol mebutate gel (0.05% and 0.015%). Photodynamic therapy is a procedural field therapy. Important considerations when developing a comprehensive treatment plan include patient risk factors; the number and location of AK lesions; strategies for minimizing sun exposure; and the mechanism of action, clearance rate, adverse effect pro!le, and application of local and topical therapies.