Childhood cancer in the United States. A geographical analysis of cases from the Pediatric Cooperative Clinical Trials groups.

BACKGROUND: After injuries, cancer is the leading cause of death in children younger than 15 years in the United States. Despite dramatic increases in 5-year survival rates, more than 100,000 person-years of life are lost to childhood cancer each year. The exact proportion of pediatric cancer patients who receive care at centers that utilize up-to-date therapeutic protocols [such as those affiliated with the Childrens Cancer Group (CCG) or the Pediatric Oncology Group (POG)] remains unknown. The purpose of this study was to estimate the proportion and geographic distribution of childhood cancer patients in the United States who are seen at participating centers of the CCG and the POG.
METHODS: Patients included 21,026 incident pediatric cancer cases diagnosed from January 1, 1989 through December 31, 1991. Observed numbers of pediatric cancer cases were compared with expected numbers of cases calculated from incidence rates obtained from the Surveillance, Epidemiology, and End Results (SEER) Program and population counts obtained from the 1990 U.S. Census Bureau.
RESULTS: Approximately 94% of children younger than 15 years diagnosed with cancer are seen at an institution that is a member of either POG or CCG. Comparisons of the observed-to-expected numbers of incident cases in the age groups (birth-4 years, 5-9 years, 10-14 years, and 15-19 years) demonstrated ascertainment rates of 100, 93, 84, and 21%, respectively. In some regions within the United States the observed number of cases was significantly less than that expected number, including areas of Idaho, Oklahoma, and Virginia. In addition, there were areas in which the observed number of childhood cancer cases was substantially greater than that expected, including areas in California and Florida.
CONCLUSIONS: The membership of the cooperative clinical trials groups (the POG and CCG) ascertain and provide access to state-of-the-art treatment protocols for the vast majority of pediatric cancer patients in the country. For the younger age groups, the CCG and POG may represent a mechanism of case ascertainment that approximates a population-based series for the continental United States. Those areas that have large enough discrepancies in observed-to-expected numbers may warrant further investigation.