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Section of Evidence Synthesis and Classification

WHO Classification of Tumours Group


Cancer classification has previously been based on consensus of histopathological opinion, with very limited molecular input. However, pathology is undergoing a more rapid transformation than at any time during the past 30 years, due to the introduction of new technologies to practice. The understanding of cancer at a molecular level is now at a point where it needs to be integrated into cancer diagnosis. Digital pathology and image analysis are now also producing new insights, and providing justification of many existing diagnostic criteria, while challenging others. Finally, the pace of improvement in computer technology, including artificial intelligence, is already producing clinically applicable aids to diagnosis, and this trend is likely to accelerate. There is an urgent need to integrate these facets of diagnosis into a globally accepted cancer classification.

The WHO Classification of Tumours series (WHO Blue Books) provides an evidence-based classification of all cancer types to enable diagnosis and research worldwide.

Pathologists need timely synthesis and evaluation for tumour classification based on expert consensus review of peer-reviewed published evidence. The definitions are incorporated into the International Classification of Diseases (ICD) codes. The WHO Blue Books provide the user with a unique synthesis of histopathological diagnosis with digital and molecular pathology to guide cancer diagnosis. The diagnosis and classification of individual cancers underpins treatment of individual patients, as well as research into all aspects of cancer causation, prevention, therapy, and education.

The WHO Blue Books contribute to the Agency′s mission of monitoring global cancer occurrence, since without clearly defined histopathological and genetic diagnostic criteria, epidemiological and clinical studies are difficult to conduct.

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