Correlation Between Online Case-based Training of Pathologists in Dermoscopic Images and Diagnostic Accuracy in Histopathological Interpretation of Skin Lesions Suspicious of Melanoma

Background Several publications suggest that the increasing melanoma incidence may partly be caused by histopathological overdiagnosis (Glasziou) and that the consequences of missing a melanoma may be one reason for this (Titus, L. J.). Pathologists provide the current gold standard in skin lesion diagnostics (Elmore 2017), primarily based on the interpretation of histological slides. Still, it has been suggested that pathologists' diagnostic accuracy and confidence could be improved if they gained access to additional clinical information and in vivo clinical and dermoscopic images of melanocytic tumors (Scolyer, Elder). The inter-rater reliability is significantly enhanced when pathologists are provided with dermoscopic and clinical images of the lesion during histopathological interpretation (Bauer, J.). This effect is especially pronounced among expert dermatopathologists who are proficient at evaluating dermoscopic images (Ferrara). However, interpreting dermoscopic images is challenging, and mastery typically requires several years of clinical experience (Ternov). Chevolet et al. reported in 2015 a significant difference in the interpretation of dermoscopic images between novices and clinicians with former dermoscopy training (Chevolet). The learning journey can be significantly shortened if the trainee receives comprehensive training in pattern recognition for dermoscopy and clinical images with immediate, accurate, and individualized feedback and access to a library with a large selection of skin lesion cases (Ericsson, Nervil). Recent studies in Denmark have shown that General Practitioners can increase their diagnostic accuracy by up to 10,5% by using a Large-scale Interactive Image Repository (LIIR) app for a few hours (Nervil). This method has yet to be tested on pathologists, which is what we indeed intend to do in this project.

Previous studies have focused only on melanocytic lesions (Elmore, Elder, Piepkorn, Ferrara). Still, most pathologists will receive both melanocytic and pigmented non-melanocytic lesions (seborrheic keratoses, dermatofibromas, etc.) clinically suspected of being melanoma. The current practice in preparing histological specimens involves creating standardized sections based on the clinician's assessment of the diagnosis and the size of the skin lesion. However, there is often no consideration of potentially suspicious areas within the skin lesion, and standard sectioning, staining, and subsequent evaluation may not occur in the most clinically suspicious areas. Previous studies have highlighted the importance of clinical information for accurate assessment of skin lesions, particularly melanocytic lesions (Scolyer), yet standardized clinical information for histopathological examination has not been systematically implemented in Denmark, likely due to a lack of technology enabling easy information sharing across medical specialties and healthcare sectors. Improving pathologists' diagnostic accuracy is crucial to ensuring patients receive the correct treatment. Dermoscopic images and training in their interpretation could be the future of histopathological skin lesion training.

Hypothesis Digital training in dermoscopy and clinical image interpretation improves diagnostic accuracy, confidence, and ease of skin lesion assessment among pathologists compared to those without such training.

Aim This study aims to evaluate the impact of dermoscopy training on pathologists' assessment of melanoma-suspected skin lesions.

Method The DAHT project includes an unfiltered selection of 203 clinically melanoma-suspect skin lesions excised at a specialized surgical department and consists of dermoscopic and clinical images, along with clinical information about the patients and skin lesions; this material is referred to as "DAHT cases". These cases will be assessed by the participating pathologists in a randomized order, and both individual and group performance will be analyzed.