Digital Pathology for the Primary Diagnosis of Breast Histopathological Specimens: An Innovative Validation and Concordance Study

Aim: To train and individually validate a group of breast pathologists in specialty specific digital primary diagnosis using a novel protocol endorsed by the Royal College of Pathologists’ new guideline for digital pathology. The protocol allows early exposure to live digital reporting, in a risk mitigated environment, and focusses on patient safety and professional development. Methods and Results: 3 specialty breast pathologist completed training in use of a digital microscopy system, and were exposed to a training set of 20 challenging cases, designed to help them identify personal digital diagnostic pitfalls. Following this, the 3 pathologists viewed a total of 694 live, entire breast cases. All primary diagnoses were made on digital slides, with immediate glass review and reconciliation before final case sign out. There was complete clinical concordance between the glass and digital impression of the case in 98.8% of cases. Only 1.2% of cases had a clinically significant difference in diagnosis/prognosis on glass and digital slide reads. All pathologists elected to continue using the digital microscope as standard for breast histopathology specimens, with deferral to glass for a limited number of clinical/histological scenarios as a safety net. Conclusion: Individual training and validation for digital primary diagnosis allows pathologists to develop competence and confidence in their digital diagnostic skills, and aids safe and responsible transition from the light microscope to the digital microscope.