Risk of childhood cancer for infants with birth defects. I. A record-linkage study, Atlanta, Georgia, 1968-1988.

To evaluate the risk of childhood cancer among infants with serious birth defects, the authors linked records of the population-based registry of the Georgia Center for Cancer Statistics for 1975 to 1988 with records 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 was diagnosed in 400 children younger than 15 years of age. The observed number of children with a defect who developed cancer was compared with the number expected on the basis of the cancer registry rates. Of the 19,373 children with birth defects, 31 developed cancer (standardized incidence ratio (SIR) = 2.2, 95% confidence interval (CI) 1.5-3.2). Two associations were found: of 532 children with Down's syndrome (trisomy 21), three developed acute leukemia (SIR = 50.8, 95% CI 10.5-148.5) while of 746 children with pyloric stenosis, four developed cancer (SIR = 7.5, 95% CI 2.0-19.3). These data show that children with selected birth defects are at increased risk for specific childhood cancers. Such record-linkage can reveal new associations, which can in turn help researchers understand underlying mechanisms common to teratogenesis and carcinogenesis.