SEER Training Modules

Corresponding Numbers in ICD-O-2

Figure 14. ICD-O, Third Edition, Rules and their Corresponding Numbersin ICD-O, Second Edition

Subject ICD-O ICD-O
Topographic regions and ill-defined sites A 2
Prefixes B 3
More than one topographic category or subcategory C 4
Topography codes for lymphomas D 12
Topography code for leukemias E 13
Behavior code F 5
Grading or differentiation G 6
Site-associated morphology H 8,9
Compound morphology diagnoses J 10
Coding multiple morphology terms K 11

*Notes: Second Edition rule 1 described the structure of the 10-digit code.
Second Edition rule 7 described the differences between the terms "cancer" and "carcinoma."
Second Edition rule 14 described the issues in coding multiple neoplasms.
There is no Rule I in the Third Edition to avoid possible confusion with a Rule 1.