H&E stained formalin fixed paraffin embedded core biopsies from ten patients were digitized using the Philips Ultra-Fast Scanner at 20X magnification. The gold standard was a set of manual annotations, confirmed by a dedicated urologic pathologist. The CNN was trained on 150 annotated biopsy fragments to differentiate between the different Gleason scores. The GGG were constructed out of the two Gleason grades with highest percentages, dividing grade groups 1, 2 and >3, based on the clinical consequence. A test set, which consisted of 15 biopsy fragments that were not used in the training of the CNN, was generated. The accuracy was calculated by dichotomizing the grading of the test set, in order to separate the different treatment groups, and comparing this result to the classification in the pathology report.
In distinguishing GGG <I from > II, the CNN shows a sensitivity, specificity and accuracy of 65%, 93% and 75%, respectively. Distinguishing GGG <II from III shows a sensitivity, specificity and accuracy of 100%, 67% and 73% respectively.
This feasibility study shows the potential value of a CNN in the grading of PCa. Naturally, in order to validate the results of CNN, multiple pathologists need to confirm the gold standard to correct for the inter-observer variation. A larger and more heterogeneous dataset is required to further validate these results.
Presented by: Jansen I
Affiliation: Academic Medical Center, Amsterdam, The Netherlands
Written by: Hanan Goldberg, MD, Urologic Oncology Fellow (SUO), University of Toronto, Princess Margaret Cancer Centre.Twitter: @GoldbergHanan at the 37th Congress of Société Internationale d’Urologie - October 19-22, 2017- Lisbon, Portugal