Validation of a diagnostic algorithm for the discrimination of actinic keratosis from normal skin and squamous cell carcinoma by means of high definition optical coherence tomography
Actinic keratoses (AKs) commonly arise on sun damaged skin. Visible lesions are often associated with subclinical lesions on surrounding skin, giving rise to field cancerization. To avoid multiple biopsies to diagnose subclinical/early invasive lesions, there is an increasing interest in non invasive diagnostic tools, such as high definition optical coherence tomography (HD OCT) We previously developed a HD OCT based diagnostic algorithm for the discrimination of AK from squamous cell carcinoma (SCC) and normal skin. The aim of this study was to test the applicability of HD OCT for non invasive discrimination of AK from SCC and normal skin using this algorithm. Three dimensional (3D) HD OCT images of histopathologically proven AKs and SCCs and images of normal skin were collected. All images were shown in a random sequence to three independent observers with different experience in HD OCT, blinded to the clinical and histopathological data and with different experience with HD OCT. Observers classified each image as AK, SCC or normal skin based on the diagnostic algorithm. A total of 106 (38 AKs, 16 SCCs and 52 normal skin sites) HD OCT images from 71 patients were included. Sensitivity and specificity for the most experienced observer were 81.6% and 92.6% for AK diagnosis and 93.8% and 98.9% for SCC diagnosis. A moderate interobserver agreement was demonstrated. HD OCT represents a promising technology for the non invasive diagnosis of AKs. Thanks to its high potential in discriminating SCC from AK, HD OCT could be used as a relevant tool for second level examination, increasing diagnostic confidence and sparing patients unnecessary excisions.
Experimental dermatology