INTRODUCTION
Actinic Keratosis (AK) is a recurring premalignant lesion that arises from prolonged and intermittent sun exposure.1 In the United States, AK is the second most frequent diagnosis made by dermatologists.2 Worldwide, the number of cases continues to rise, with the highest prevalence among countries with high levels of sunlight and populations with light skin tones.2,3 UV radiation from sunlight can induce dysplastic proliferation of keratinocytes, resulting in the formation of AK.3 AKs have a 0.025% to 16% chance of progression to cutaneous squamous cell carcinoma (cSCC).4 Individuals with a higher burden of AKs carry an increased risk of transformation.5 Due to the underlying risk for malignant transformation, AKs require treatment.4,5
Individual AKs are treated with lesion-directed therapy.6 For multiple AKs located in one area, field-directed therapy is the treatment of choice.6 Field-directed therapies include the FDA- approved topical agents 5-Fluorouracil (5-FU), imiquimod, diclofenac, tirbanibulin, and photodynamic therapy.7 Field cancerization is a term used to describe areas of skin affected by chronic UV radiation.8 The affected skin region can develop visible AKs and also harbor subclinical AKs. In order to effectively treat the entire region, field-directed therapy is required.9 5-FU 5% cream is thought to be a more effective field-directed therapy when compared to imiquimod cream, ingenol mebutate gel, and PDT, based on a single-blind study – but no comparative data available vs the recently FDA-approved tirbanibulin 1% ointment (2020).7,10 However, topical 5-FU requires multiple daily applications, long durations of treatment, and can cause severe cutaneous and systemic adverse effects.11 These factors decrease patient adherence and real-world effectiveness.11 A negative experience with topical treatment may prevent patients from seeking treatment for AK in the future.11,12,13
Individual AKs are treated with lesion-directed therapy.6 For multiple AKs located in one area, field-directed therapy is the treatment of choice.6 Field-directed therapies include the FDA- approved topical agents 5-Fluorouracil (5-FU), imiquimod, diclofenac, tirbanibulin, and photodynamic therapy.7 Field cancerization is a term used to describe areas of skin affected by chronic UV radiation.8 The affected skin region can develop visible AKs and also harbor subclinical AKs. In order to effectively treat the entire region, field-directed therapy is required.9 5-FU 5% cream is thought to be a more effective field-directed therapy when compared to imiquimod cream, ingenol mebutate gel, and PDT, based on a single-blind study – but no comparative data available vs the recently FDA-approved tirbanibulin 1% ointment (2020).7,10 However, topical 5-FU requires multiple daily applications, long durations of treatment, and can cause severe cutaneous and systemic adverse effects.11 These factors decrease patient adherence and real-world effectiveness.11 A negative experience with topical treatment may prevent patients from seeking treatment for AK in the future.11,12,13
