Patterns of enrollment on cooperative group studies. An analysis of trends from the Los Angeles County Cancer Surveillance Program.

To assess the proportion of children diagnosed with cancer who are enrolled on studies conducted by the two national pediatric cooperative groups, population-based cancer incidence data for Los Angeles county children younger than age 20 for the years 1980 through 1987 were linked with patient records of children registered with the Childrens Cancer Group (CCG) or the Pediatric Oncology Group (POG). For patients not enrolled on a protocol, demographic and disease characteristics were compared with summary eligibility requirements for CCG protocols that were open for enrollment during 1980-1987. The proportion of patients enrolled on studies conducted by the cooperative groups varied with tumor type and age at diagnosis. When patients younger than the age of 10 were diagnosed at an institution affiliated with one of the groups, the majority of those evaluated by our review as eligible for a study were enrolled on a protocol. The proportion of young patients entered on study among those whose diagnosis was not made at a cooperative group institution was generally smaller. Seventy-three percent of all potentially eligible patients with acute leukemia diagnosed between 1980-1987 were entered on a pediatric group protocol. Approximately 50% of all potentially eligible patients with brain tumors were entered on protocol. In contrast to this, less than 50% of patients older than the age of 14 and likely to be eligible for a study were entered on a pediatric group protocol, regardless of the tumor type. Indeed, bone tumors constituted the category of patients most likely to be enrolled, with 39% of all potentially eligible patients entered on a study in the period examined. If the patient's diagnosis was made at a cooperative group institution, the individual was more likely to be entered on a protocol than if the diagnosis was made at a center outside the cooperative group network. It was not possible to determine the precise reason for this trend from the data available. Some explanations include policies at cooperative group institutions regarding admission of patients older than age 14 and the availability of protocols from cooperative groups primarily focused on the treatment of cancers of adults.