Version 24
Data Item #523: Behavior Code ICD-O-3

Code for the behavior of the tumor being reported using ICD-O-3. NAACCR adopted ICD-O-3 as the standard coding system for tumors diagnosed beginning January 1, 2001, and later recommended that prior cases be converted from ICD-O-2. See Behavior (92-00) ICD-O-2 [430], for ICD-O-2 codes.

Juvenile astrocytoma is coded as borderline in ICD-O-3; North American registries report as 9421/3.

Clarification of Required Status

Behavior is required by all standard-setting organizations for tumors diagnosed on or after January 1, 2001, and recommended (by conversion from ICD-O-2 codes) for tumors diagnosed before 2001.

When the histologic type is coded according to the ICD-O-3, the histology code must be reported in Histologic Type ICD-O-3 [522], with behavior coded in Behavior Code ICD-O-3 [523].

For information on required status for related data items for histologic type and behavior when coded according to ICD-O-2, see Histology (92-00) ICD-O-2 [420] and Behavior (92-00) ICD-O-2 [430].

digits

0-3, Refer to ICD-O-3