A UNIFORM HISTOLOGICAL CLUSTER SCHEME FOR ICD-O-CODED PRIMARY CENTRAL-NERVOUS-SYSTEM TUMORS

Comparability of population-based measures of risk and prognosis for p rimary central nervous system (CNS) tumors, which exhibit marked histo logical diversity, may be hampered by differences in detection and cas e ascertainment and by the lack of unequivocal and uniform histologica l criteria for pathological diagnoses. Furthermore, many cancer regist ries do not include benign tumors as defined by the international Clas sification of Diseases for Oncology (ICD-O), such as meningiomas, schw annomas and pituitary adenomas. We propose both a detailed and a rough uniform histological cluster scheme for data coded according to the f irst or second edition of the ICD-O, published in 1976 and 1990, respe ctively. Primary CNS tumors, typed and graded according to (modified) classification systems of Bailey and Gushing, Kernohan, Ringertz, the WHO and Daumas-Duport, are clustered as clinically relevant entities o n the basis of the second edition of the WHO classification system, pu blished in 1993. The proposed scheme identifies some of the (potential ) pitfalls in the descriptive epidemiology of CNS tumors and may facil itate temporal and geographical comparability of population-based data .