California Cancer Reporting System Standards Volume I: Abstracting and Coding Procedures
Certain combinations of histology and primary site codes indicate errors in coding. The CCR data management system (Eureka) edits the data and rejects false combinations. False combinations (edit errors) must be corrected before the data management system can store the data and make it available for research.
Disallowed combinations are of two types:
Those involving the first four digits of the histology field (morphology code).
Those involving the behavior code (fifth digit of the histology field).