Reliable methods to evaluate the burden of actinic keratoses

Dermatologists treat actinic keratoses to prevent non-melanoma skin cancer. Evaluation of actinic keratosis therapy depends on reliable measures of the lesions. The commonly used method of directly counting all visible lesions has been shown to be unreliable. We performed a prospective, single-blinded study to explore the reliability of body surface area involvement and direct counting of lesions measuring greater than 0.5 cm. Consecutively available subjects with >2% body surface area involvement of both upper extremities were recruited from the Albuquerque, NM Veterans Administration Dermatology Clinic upon their arrival. Blinded investigators evaluated 37 subjects during two visits, baseline and 2 weeks later, using both methods. Data were analyzed using the 26 pairs where evaluating physician was the same at both time points. Both methods correlated well when comparing the two time points. Our results did not change when we added the pairs where the evaluating physician differed in the two time points. Our study demonstrates that both methods are viable ways to evaluate actinic keratoses, even when the investigators differ at different time points, a practical matter in clinical trials. Our study provides a promising option to evaluate emerging new actinic keratoses therapies. However, given that the method was only tested on upper extremities of a veteran population, further testing must be performed in different anatomical locations and in non-veteran populations.