About ICD-O

The International Classification of Diseases for Oncology (ICD-O)1 has been used for more than 35 years, principally in tumour or cancer registries, for coding the site (topography) and the histology (morphology) of the neoplasm, usually obtained from a pathology report.

By agreement with the College of American Pathologists, the morphology section of ICD-O is incorporated into the Systematized Nomenclature of Medicine (SNOMED)2,3 classification as the neoplasm section of the morphology field.

The International Classification of Diseases for Oncology, Second Edition4 was published in 1990, followed by the International Classification of Diseases for Oncology, Third Edition5 in 2000. The topography section of the third edition remained the same as in the second edition, which was based on the neoplasm section of the International Statistical Classification of Diseases and Related Health Problems, 10th Revision (ICD-10)6. However, the morphology section was revised. New classifications, especially for lymphomas and leukaemias, were introduced, and new codes assigned to accommodate them. Although one of the prime commitments of the editors was to change as few terms as possible, to add new terms at empty spaces, and not to reuse previously assigned codes, this was not always possible. In order to keep groups of similar entities together, the codes for some terms had to be changed. Furthermore, the sequence or grouping of terms may not always be as logical as possible because of the limitations of available code numbers.

In developing the previous editions and the present edition of ICD-O, a particular effort was made to use the nomenclature appearing in the World Health Organization International Histological Classification of Tumours series (WHO “Blue Books”)7. This series covers all the principal sites of cancer and includes the morphology codes of ICD-O for each neoplasm.

Since the initial publication of the third edition of ICD-O (ICD-O-3) in 2000, updates to the WHO Blue Book series have continued. During the development of the fourth edition of the Blue Book volumes, chapter authors worked with the International Agency for Research on Cancer/International Classification of Diseases for Oncology (IARC/ICD-O) Committee for ICD-O-3 to review recently identified neoplasm entities and assign morphology codes. This updated version of ICD-O-3 (ICD-O-3 First Revision, or ICD-O-3.1) includes the new terms, codes, synonyms, related terms, morphology, and behaviour code changes from the WHO Blue Books published between 2007 and 2010 on tumours of haematopoietic and lymphoid tissues8, the central nervous system9, and the digestive system10.


References

1. International Classification of Diseases for Oncology, first edition. Geneva, World Health Organization, 1976.

2. Cote RA, editor. Systematized nomenclature of medicine. Vols I and II. Skokie, IL, College of American Pathologists, 1977.

3. Cote RA et al., editors. SNOMED International: the systematized nomenclature of human and veterinary medicine. Vols I-IV. Northfield, IL, College of American Pathologists, 1993.

4. Percy C, Van Holten V, Muir C, editors. International Classification of Diseases for Oncology, second edition. Geneva, World Health Organization, 1990.

4. Fritz A, Percy C, Jack A, Shanmugaratnam K, Sobin L, Parkin DM, Whelan S , editors. International Classification of Diseases for Oncology, third edition. Geneva, World Health Organization, 2000.

6. International Statistical Classification of Diseases and Related Health Problems. Tenth Revision. Vols 1-3. Geneva, World Health Organization, 1992-1994.

7. International histological classification of tumours, 2nd ed. Geneva, World Health Organization, 1981-2000.

8. Swerdlow SH et al., editors. WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues, 4th edition. Lyon, International Agency for Research on Cancer, 2008.

9. Louis DN et al., editors. WHO Classification of Tumours of the Central Nervous System, 4th edition. Lyon, International Agency for Research on Cancer, 2007.

10. Bosman FT et al., editors. WHO Classification of Tumours of the Digestive System, 4th edition. Lyon, International Agency for Research on Cancer, 2010.