Medulloblastoma and Collins' law: a critical review of the concept of a period of risk for tumor recurrence and patient survival.

Collins' law (CL) states that the period of risk for recurrence for a tumor is the age of the patient plus 9 months. Originally a clinical observation in Wilms' tumor, CL has been applied to other tumors such as medulloblastoma (MB). Although CL does not apply to all childhood tumors, it seems to be a valid observation for childhood MB, despite several reports of violations or exceptions to CL in the literature. We sought to test CL in a large population of children with MB from the Childhood Brain Tumor Consortium (CBTC). We analyzed data from 602 children with MB, of whom 421 died and 181 were censored but alive at the last follow-up. We found 16 additional CL exceptions to supplement the 22 already present in the literature. This is both the greatest number of exceptions and the largest MB study population for CL reported to date. We provide clinical data on our 16 uncensored exceptions to CL and critically review those 22 cases cited previously in the literature. All of the CBTC exceptions were under 6 years of age at the time of initial diagnosis and were followed for an average of 7.5 years. All 16 CBTC exceptions died. Children older than 8 years of age could not be followed for a sufficient period of time to be able to state whether CL applies; as age at initial diagnosis increases, the period of observation required to determine CL validity becomes impractically long. Exceptions to CL are rare and amounted to 3.8% of 405 uncensored CBTC patients who died.(ABSTRACT TRUNCATED AT 250 WORDS)