ICD-O-3 Coding Materials

ICD-O-3 Guidelines

The revised 2021 Guidelines for ICD-O-3.2 Histology Code and Behavior Update for cases diagnosed 1/1/2021 forward are now available on the NAACCR website. The update includes links to tables listing new codes and other changes and is available in two formats: PDF and Excel. Also available are the 2021 ICD-O-3.2 Update Guidelines.

The NAACCR ICD-O-3 Implementation Work Group highly recommends all users read the guidelines which contain important coding information related to the 2021 update.

ICD-O-3 SEER Site/Histology Validation Lists

The Site/Histology List is not intended to be used for case finding or to determine reportability.

The ICD-O-3 Site/Type Validation program was modified to only allow for the site/histology/behavior combinations listed in this publication. All other cases must be reviewed.

• ICD-O-3 SEER Site/Histology Validation List (06/29/2020): PDF (PDF, 667 KB) or Excel (XLSX, 437 KB)
  • 6/29/2020 Errata (PDF, 459 KB)
  • 07/11/2019 Errata (PDF, 9 KB)
  • 06/18/2019 Errata (PDF, 12 KB)

IMPORTANT: The changes listed in this errata apply to cases diagnosed 1/1/2021 forward.  They do not apply to cases diagnosed prior to 1/1/2021.

Refer to the ICD-O-3 Archive for older reference documents.

The International Agency for Research on Cancer (IARC) provides an electronic version of ICD-O-3 on their website. However, the IARC versions are not identical to the versions used in the U.S. See the ICD-O-3 errata on this website and the NAACCR ICD-O-3 implementation guidelines for U.S. instructions.