Intensity of Local Skin Reactions During 5-Fluorouracil Treatment Related to the Number of Actinic Keratosis Lesions: A Post Hoc, Exploratory Analysis

In order to prevent recurrence of actinic keratosis lesions and their progression to invasive squamous cell carcinoma, topical treatment of actinic keratosis often involves treating the field of cancerisation to clear visible and subclinical lesions. The occurrence of local adverse skin reactions during treatment can affect patient adherence to therapy and therefore compromise efficacy. A thorough understanding of the relationships between changes in lesions, actinic keratosis remission and tolerability of topical treatments over time is necessary to manage patient expectations, ensure treatment adherence and optimise clinical outcomes. This exploratory study used pooled data from two pivotal phase III studies to compare local skin reaction severity between 5-fluorouracil 4% cream applied once daily and 5-fluorouracil 5% cream applied twice daily, then to examine the relationship between the severity of local skin reactions during treatment and the number of actinic keratosis lesions at baseline. Local skin reactions appeared to be more severe in patients with more than 10 actinic keratosis lesions at baseline than in those with 5 to 10 lesions. Using a cut-off value of 10 lesions pre-treatment, healthcare practitioners can forewarn patients accordingly of potentially more severe local adverse skin reactions in order to motivate them to complete their treatment, thus ensuring treatment efficacy. If patients are likely to experience intolerable severe skin reactions, practitioners can plan to introduce an appropriate rescue treatment.