Introduction to ICD-O-3.2

ICD-O-3.2 replaces ICD-O-3 for cancer morphology classification in US cancer registries for diagnoses beginning on 1/1/2021. At the time of this writing, ICD-O-3.2 is a table of morphology codes. No changes have been made to the topography codes. ICD-O-3 continues to be used to classify primary site/topography.

The IACR Working Group on ICD-O Updates compiled a listing of additions, changes, and revisions between ICD-O-3.1 and ICD-O-3.2 as a reference material for cancer registries.

The change documents and the morphology tables are located on the IACR website.

Updated: December 13, 2023