{"entity":{"id":"icd-o-3","kind":"term","name":"ICD-O-3 (International Classification of Diseases for Oncology)","aka":["ICD-O-3","ICD-O","ICD-O-3 morphology code","ICD-O-3 topography code","morphology code","topography code"],"tldr":"ICD-O-3 codes every tumour twice: a topography code for where it arose and a morphology code for what kind of cells it is made of and how it behaves.","summary":"The International Classification of Diseases for Oncology is a domain-specific extension of the ICD for tumour diseases, widely used by cancer registries (Wikipedia; the WHO maintains the third edition). Topography codes (C50.9, breast) and morphology codes (8500/3, invasive ductal carcinoma, malignant) appear in TCGA and SEER clinical tables and are the join key between registries and molecular cohorts. Cancer-type labels in machine-learning datasets should resolve to these codes rather than to project names.","asOf":"2026-09-24","wikipedia":"https://en.wikipedia.org/wiki/International_Classification_of_Diseases_for_Oncology","links":[{"label":"WHO: ICD-O","url":"https://www.who.int/standards/classifications/other-classifications/international-classification-of-diseases-for-oncology"},{"label":"Wikipedia","url":"https://en.wikipedia.org/wiki/International_Classification_of_Diseases_for_Oncology"}],"tags":["cansim-terms"],"related":["seer","cancer-ai-vocabulary"],"cancers":[],"sections":[],"technologies":[],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":["oncotree-term","ncit","tnm-staging"],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":["Listed in the CanSim terms map 1.0.0 (docs/onco/terms.json, generated 2026-09-24), CC BY 4.0, attribution: CanSim project, an open, public-data-first cancer foundation-model programme; CanSim page path /terms/icd-o-3."],"provenance":{"editedBy":"OnCo CanSim terms wave (Wikipedia summaries, standards and project pages, GDC and FDA pages, Europe PMC)","editedOn":"2026-09-24","note":"CanSim terms map 1.0.0 (docs/onco/terms.json, generated 2026-09-24), CC BY 4.0, attribution: CanSim project, an open, public-data-first cancer foundation-model programme"},"category":"Pathology"},"route":"/terms/icd-o-3/","neighbours":{"collection":[{"id":"seer","kind":"collection","name":"SEER (Surveillance, Epidemiology, and End Results)","route":"/collections/seer/"}],"term":[{"id":"cancer-ai-vocabulary","kind":"term","name":"Cancer AI vocabulary (CanSim terms map)","route":"/terms/cancer-ai-vocabulary/"},{"id":"mondo","kind":"term","name":"Mondo disease ontology","route":"/terms/mondo/"},{"id":"ncit","kind":"term","name":"NCI Thesaurus (NCIt)","route":"/terms/ncit/"},{"id":"oncotree-term","kind":"term","name":"OncoTree cancer classification","route":"/terms/oncotree-term/"},{"id":"tnm-staging","kind":"term","name":"TNM staging","route":"/terms/tnm-staging/"}]}}