RESUMO
The second revised edition of the standard international coding tool for cancer registration. The 1990 edition, which has been finalized following extensive field testing throughout the world, permits the coding of all neoplasms as malignant, benign, in situ, of uncertain behaviour, or metastatic. As in the previous edition, a separate code for histologic grading and differentiation has also been included. ICD-O, which comes into force before ICD-10, can be used for both topographic sites and histologic types of neoplasms by those who wish to code greater detail about a neoplasm than is provided for in the neoplasms chapter of ICD-10. Since the great majority of users are from tumor registries, the new edition features specific instructions for tumor registrars as well as for pathologists. The classification was developed in collaboration with the United States National Cancer Institute and the WHO International Agency for Research on Cancer. New features include adoption of the ICD-10 classification for tumor topography with its alphanumeric coding system, inclusion of several new histologic types in the morphology section, complete remodelling of the section on Non-Hodgkins lymphoma, and expansion of the sixth-digit code for histologic grading and differentiation in order to identify T- and B-cell involvement for lymphomas and leukemias
