Risk Stratification: Should All Actinic Keratoses in All Patients Be Treated?

Abstract

Actinic keratoses (AKs) are foci of dysplastic keratinocytes in the epidermis. They are markers of both photodamage and risk of keratinocyte carcinoma (KC) formation. Individual AKs are thought to progress to KC uncommonly, although they arise from the same UV-induced mutations which give rise to KC. Thus, the rationale for treatment of AKs is to reduce the risk of KC formation since AKs are not dangerous in themselves. An estimated $1.68 billion is spent on treatment of AKs in the United States annually. Treatment of a region of skin (e.g., face, scalp, or forearms) to clear AKs is termed field treatment. Though field treatment of AKs and actinic damage has been associated with a reduction in cutaneous squamous cell carcinoma (CSCC), it is unclear to what degree treatment of individual lesions positively impacts health. The presence of AKs has been correlated with formation of KC, particularly CSCC. Field treatment can be accomplished by topical therapy [photodynamic therapy (PDT), topical 5-fluorouracil, ingenol mebutate, imiquimod, and/or sunscreen] or oral systemic therapy including nicotinamide or retinoids (i.e., acitretin, isotretinoin). Field treatments have been associated with a reduction in KC and therefore are likely cost-effective. However, there is a lack of data showing that treatment of individual AK lesions (usually accomplished via cryotherapy) reduces KC. Although cryotherapy is only associated with a 4% sustained clearance rate at 1 year, more than three times the amount of money is spent on cryotherapy as compared to topical therapy in Medicare patients. Field treatment is superior to cryotherapy for reduction of KC. However, it requires high patient compliance and increasingly entails high out-of-pocket expenses for patients. Since field-directed and systemic therapies of AKs reduce KC formation, allocation of resources should be directed toward these modalities. Efforts should be made to improve patient access to field treatments by increased reimbursement for photodynamic therapy (both standard and daylight), reduction of out-of-pocket expenses for topical treatments and retinoids, and increased use of nicotinamide in patients with field actinic damage.