American Joint Committee on Cancer (AJCC) Brain and Spinal Cord Cancer Staging System, version 9. New content 9. Brain and spinal cord are presented in an organization’s tumor staging system World Health Organization (WHO) simple, easy-to-use and inclusive. . Clinicians, registrars, researchers and other content users will benefit from the updated brain and spinal cord content, along with tables and explanations. Version 9 of the Brain and Spinal Cord Cancer Classification System will take effect on January 1, 2023 and will replace the 8th Edition Brain and Spinal Cord Cancer site content.