California Cancer Reporting System Standards Volume I: Abstracting and Coding Procedures
Tumor grade is the most important prognostic indicator for response to therapy and outcomes for brain and spinal cord tumors. According to the World Health Organization (WHO), the classification is more of a “malignancy scale” than a strict histologic grading system. Therefore, the WHO grade is different from the ICD-O grade/differentiation value that is stored with the morphology code.
Do not use WHO grade to code the sixth digit of the ICD-O morphology code.
Code the WHO grade classification as documented in the medical record in Collaborative Staging Site Specific Factor 1, for brain and other central nervous system sites.
WHO Classifications:
WHO grade I generally describes non-malignant or benign tumors; however, non-malignant tumors should not be coded as grade I unless WHO grade is specifically stated in the source document.
WHO grade II generally describes a malignant tumor but it can describe a non-malignant tumor depending on histologic type.
WHO grade III and IV describe malignant tumors.
For certain types of CNS tumors, no WHO grade is assigned.
For additional information, please see: