MEDULLOBLASTOMA AND COLLINS LAW - A CRITICAL-REVIEW OF THE CONCEPT OFA 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 o bservation in Wilms' tumor, CL has been applied to other tumors such a s medulloblastoma (MB). Although CL does not apply to all childhood tu mors, it seems to be a valid observation for childhood MB, despite sev eral reports of violations or exceptions to CL in the literature. We s ought to test CL in a large population of children with MB from the Ch ildhood Brain Tumor Consortium (CBTC). We analyzed data from 602 child ren with MB, of whom 421 died and 181 were censored but alive at the l ast 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 a nd 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 1 6 CBTC exceptions died. Children older than 8 years of age could not b e followed for a sufficient period of time to be able to state whether CL applies; as age at initial diagnosis increases, the period of obse rvation 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. Some exceptions to a clinical observation are alway s expected, but application of CL to children below the age of 8 years seems to be a useful predictor of survival in childhood MB.