3.2 | Disease Classifications and Risk Stratification
ICD-O-3 codes and ICCC-3 were used to further group patients to align with the BCCSS. In the final analytic survivorship cohort, there were 225 patients with leukemia, 275 with CNS tumors, and 365 patients with extracranial solid tumor or lymphoma. Based on the BCCSS risk stratification system,6 there were 191, 496, and 158 low, intermediate, and high risk survivors, respectively.