Malignant Potential of Actinic Keratoses and the Controversy Over Treatment

Abstract

Dermatologists routinely treat actinic keratoses (AKs) based on the belief that these lesions are premalignant and that treatment reduces morbidity. Marks et al¹make a convincing case for conservative management by suggesting that malignant transformation of AKs is rare and that metastasis from such transformation is uncommon. They present their data as the relationship between AKs detected during an initial visit and squamous cell carcinoma (SCC) on examination 1 year later. Using this lesion-oriented approach, Marks and colleagues^1,2have shown that the average malignant transformation rate for an actinic keratosis is only a fraction of a percent per year. Previous clinical estimates of malignant potential ranged as high as 25% and were based on patients with several AKs followed up for many years.^3,4Historical estimates were thus more patient oriented. We will present a mathematical model resulting in patient-oriented statistics that can be more easily compared with