INTEGRATED DECISION-SUPPORT SYSTEM IMAGE ARCHIVE FOR HISTOLOGICAL TYPING OF BREAST-CANCER USING A RELATION ORIENTED INFERENCE SYSTEM

Histological typing of invasive breast cancer according to the World H ealth Organisation criteria is prognostically relevant, because some h istological subtypes have a markedly better prognosis. However, reprod ucibility of histological typing is not high because of the absence of strict typing criteria, variations in the application of the typing c riteria and the usually limited illustration of the relevant criteria. The aim of this study was to develop an expert system based on highly structured histological typing criteria, integrated with high-quality microscope images to illustrate the typing criteria. This system shou ld be useful as a decision support system in the diagnosis of breast c ancers and should increase the reproducibility of histological typing. Criteria for typing were extracted from textbooks and, based on exper ience, these criteria were structured and implemented in the Relation Oriented Inference System (ROIS), in which information can be structur ed by defining relations. Illustrative black and white images were dig itized and integrated into the shell. The performance of the resulting decision support system was evaluated by a group of six pathologists using a set of slides covering the spectrum of the most frequently occ urring histological types of invasive breast cancer. The pathologists first assessed histological type according to standard morphological p rocedures. The cases were then reassessed with the decision support sy stem available for consultation. The use of the decision support syste m appeared to influence the previously assessed histological type in a bout half of the cases. Using the decision support system, histologica l typing was more uniform and more in accord with a 'gold standard' se t by two experts. The integrated decision support system/image archive for histological typing of breast cancer seems to be a useful instrum ent in daily diagnostic breast histopathology as well as being a poten tial teaching tool. It; may contribute to a more reproducible and prog nostically relevant histological typing of breast cancer.