IACR Official Website - International Association of Cancer Registries

ICD-O

INTERNATIONAL CLASSIFICATION OF DISEASES FOR ONCOLOGY (ICD-O)

International Classification of Diseases, 4^th Edition (ICD-O-4) -  consultation period closed as of 31st May 2025

• Comments received during the consultation rounds have been addressed.  
• Following comments from the users, additional 4th digit of topography codes is proposed for some cancer sites.

Alongside the ICD-O-4 morphology and topography list, we are providing listings of additions, changes, and revisions between ICD-O-3.2 and ICD-O-4 as reference material for cancer registries in the following tables:

1. New morphology codes:
   1. First 4 digits present in ICD-O-3.2 and 5^th digit different from “0”
   2. First 4 digits present in ICD-O-4, but not in ICD-O-3.2
2. Changes between ICD-O-3.2 and ICD-O-4:
   1. Morphology at the 4-digit level
   2. Topography

After the consultation period, ICD-O-4 will be reviewed, and the book generated as an online pdf (to be announced by IACR and on this website once available).

ICDO- THIRD EDITION, SECOND REVISION MORPHOLOGY

• A summary of the main changes
• Terms that are changing behaviour
• New codes and their terms
• Deleted codes and their terms
• Updated table: "Groups of malignant neoplasms considered to be histologically different for the purpose of defining multiple tumours" to be used with ICD-O-3.2 (The rest of the multiple primary rules remain unchanged.)

A LISTING OF ALL ADDITIONS, CHANGES AND REVISIONS TO THE ICD-O-3, IST REVISION (ICDO-O-3.1) FOR ICD-O-3.2

• Japanese Translation

Third edition Edited by A. Fritz, C. Percy, A. Jack,  K. Shanmugaratnam, L. Sobin,D.M. Parkin  and S. Whelan

Please consult the previous versions online and the new links for ICD-O (2nd revision) as follows:

ICD-O 3

ICD-O 3 (1st rev)

As it is no longer possible to maintain and update the previous http://codes.iarc.fr website, it was decommissioned on 31 July 2019. IARC is updating its web domain and it is not possible to maintain this website on the new platform. We apologize for any inconvenience as a result of the decommissioning.

¹ Ian Cree, Jacques Ferlay, Robert Jakob, Brian Rous, Reiko Watanabe, Valerie White, Ariana Znaor

² Atul Budukh, Jacques Ferlay, Keri Green, Tomohiro Matsuda, Brian Rous, Ariana Znaor