RISK OF CHILDHOOD-CANCER FOR INFANTS WITH BIRTH-DEFECTS .1. A RECORD-LINKAGE STUDY, ATLANTA, GEORGIA, 1968-1988

To evaluate the risk of childhood cancer among infants with serious bi rth defects, the authors linked records of the Population-based regist ry of the Georgia Center for Cancer Statistics for 1975 to 1988 with r ecords of the population-based Metropolitan Atlanta Congenital Defects Program for 1968 to 1987. During the study period, birth defects were diagnosed in 19,373 infants younger than 1 year of age, and cancer wa s diagnosed in 400 children younger than 15 years of age. The observed number of children with a defect who developed cancer was compared wi th the number expected on the basis of the cancer registry rates. Of t he 19,373 children with birth defects, 31 developed cancer (standardiz ed incidence ratio (SIR) = 2.2, 95% confidence interval (Cl) 1.5-3.2). Two associations were found: of 532 children with Down's syndrome (tr isomy 21), three developed acute leukemia (SIR = 50.8, 95% Cl 10.5-148 .5) while of 746 children with pyloric stenosis, four developed cancer (SIR = 7.5, 95% Cl 2.019. 3). These data show that children with sele cted birth defects are at increased risk for specific childhood cancer s. Such record-linkage can reveal new associations, which can in turn help researchers understand underlying mechanisms common to teratogene sis and carcinogenesis.