In the US, the Philips IntelliSite Digital Pathology Solution is presently cleared as an aid to the pathologist in the detection of HER2/neu. The newly completed clinical validation study by Philips will be submitted to FDA, with other data and information, in support of a de novo submission that, if cleared by FDA, would result in expanded indications for use. Philips IntelliSite digital pathology solution is an open platform that integrates ultra-fast slide scanners, an image management system and web based pathology case viewer.
In what Philips states is one of the largest studies ever conducted to directly compare the use of digital pathology to optical microscopes, 16 pathologists at four clinical study sites – Cleveland Clinic, University of Virginia, Miraca Life Sciences and Advanced Pathology Associates – conducted approximately 16,000 reads across 2,000 cases.
Difference in major discordance rates
The Non-inferiority study was designed to evaluate the difference in major discordance rates between diagnoses made with digital pathology or microscope. To measure this, the study had pathologists read slides obtained from cases at least one year old for which a main diagnosis was available.
With this existing diagnosis serving as the point of comparison, pathologists then read and diagnosed each case both digitally and optically with a washout period of four weeks in between. The pre-specified endpoint for the primary analysis of this study was set on a maximum of four percent difference in major discordance rates. This study endpoint successfully achieved the acceptance criterion with a final discordance rate of outcome of the study being only one percent.
Pathology is a subjective field that is dependent on how the eye of each pathologist views what appears in the microscope, says Dr. Clive Taylor, the principal investigator. “Defining how to measure and assess just how this process compares to a digital reading is complex. The design of this study holds the original diagnosis to be the truth and that provides us with a base to compare all readings by all pathologists in the study.”
Researcher Dr. Michael Feldman adds: “Proving that digital reads are not inferior to optical reads creates a foundation for a FDA submission that, if cleared, would allow for the shift to a digital operation that, in turn, may reap the additional benefits of collaboration, workflow efficiency and the use of precise tools for measurement and counting.”