Potential for melanoma diagnosis “over-calling” and “under-calling” from variation in histopathology interpretation
Background: Pathologist disagreement over the diagnosis of melanoma may harm individuals and healthcare systems. Objective: To estimate the population impact of pathology “over-calling” and “under-calling” of melanocytic lesions, and of potential solutions. Methods: We undertook simulations using published data on the prevalence and diagnostic accuracy of melanocytic histopathology in the US population. We simulated biopsy results for 10,000 patients and modelled the impact of an intervention to improve pathologist agreement on “over-calling” and “under-calling”, and of second community pathologist review. Results: For 10,000 individuals undergoing excision of one melanocytic lesion, interpreted by a community pathologist, a hypothetical intervention to improve histopathology agreement reduced the number of benign lesions “over-called” from 308 to 164 and the number of melanomas “under-called” from 289 to 240. If all uncertain diagnoses were sent for expert review, the number of referrals would decrease from 1,500 to 737 cases if formal second community pathologist was used, and to 701 cases if the hypothetical intervention was additionally used. Limitations: Hypothetical intervention. Decision thresholds to rule in or rule out melanoma may differ to those used. Conclusions: Interventions to improve histopathology agreement, and use of formal second community review, may reduce melanoma “over-calling” and “under-calling”.