JMIR Publications

ABSTRACT

Given the prevalence of keratinocyte carcinomas (KCs), it is imperative to identify accurate diagnostic tools for evaluating suspicious skin lesions. [1, 2] Misdiagnosis carries significant harms (e.g., unnecessary scarring, anxiety, increased cost). [3] A 2018 Cochrane review [3] assessed dermoscopy as an adjunct to visual inspection (VI) for KC diagnosis (verified by histology or clinical follow up) among adults with skin lesions suspicious for malignancy, or at risk of KC development. [3] Among 24 included studies, there were a total of 8805 visually-inspected lesions and 6855 lesions inspected with dermoscopy and VI. Face-to-face and teledermatology settings were evaluated separately, although no clear difference was found between settings. For in-person basal cell carcinoma (BCC) diagnosis, the diagnostic odds ratio (OR) revealed dermoscopy and VI was 8.2 times more effective than VI alone (95% CI 3.5-9.3; LR test P < 0.001), supporting the predicted sensitivity difference of 14% (79% versus 93%) at a fixed specificity of 80%, and predicted specificity difference of 22% (77% versus 99%) at a fixed sensitivity of 80%, estimated from summary receiver operating characteristic (SROC) curves. It is crucial to note that secondary to substantial heterogeneity between studies, the reported differences in sensitivity and specificity are illustrative examples of the values that might be achieved based on the observed data, and do not necessarily reflect how the tests might perform in specific settings. Sources of heterogeneity were unclear due to poor reporting and lack of available data, although the authors suggest that observer experience, type of dermatoscope used, and the case-mix of included lesions may have contributed. Risk of bias and concerns regarding applicability were generally high or unclear across most domains assessed, particularly in participant selection, flow, and timing. Although the strength of conclusions was limited, addition of dermoscopy to in-person evaluation increased diagnostic accuracy, on average. Applied to a hypothetical cohort (N=1000) at the median prevalence of 17%, an additional 24 BCC would be identified and 183 fewer non-BCC would be treated unnecessarily with use of dermoscopy and VI. Interestingly, another Cochrane review [4] compared dermoscopy and VI to VI alone for melanoma diagnosis, reporting similar results to this review, [3] but noting a significantly higher accuracy for in-person versus image-based evaluation. Insufficient data were available for thorough analysis of cutaneous squamous cell carcinoma detection, and it could not be determined whether evaluator expertise or use of a formal algorithm improved the accuracy of KC detection. Authors of this review [3] postulate that adjunctive dermoscopy may aid specialists in identifying BCC. However, results should be considered suggestive rather than conclusive, given marked heterogeneity and concerns about methodological quality of the included studies. Further investigation is required to determine any definitive benefit of dermoscopy for BCC diagnosis. Clear identification of evaluator expertise is essential to ensure meaningful results. Moreover, additional evaluation of the use of formal algorithms may benefit clinicians in varying levels of care. The ubiquity of KCs and risks of misdiagnosis underscore the need for transparent reporting of future studies, to optimize diagnostic tools and improve outcomes for patients with suspicious skin lesions.