Congenital malformations and childhood cancer

Background. We investigated the epidemiology of congenital malformations an d childhood cancer. Procedure. By employing the cases of the Registry of Ch ildhood Malignancies in Hakkaido Prefecture, Japan, from 1969 to 1996, the numbers of malignancies in cases (diagnosis at 0-14 years of age) with Down syndrome (DS), mental retardation (MR) excluding DS, luxatio coxae congeni ta (LCC), congenital heart disease (CHD) excluding DS, undescended testicle (UT), and cleft palate-lip (CPL) were calculated. Using the percentages of malignancies in the 2,349 cases without malformation, expected numbers of malignancies in the cases with the malformations were calculated. The obser ved numbers were statistically compared to expected ones. Results. in the D S cases, leukemia developed with a significantly high frequency, but no UT cases developed leukemia. No brain tumor was preceded by DS, This could not be explained only by early death from coexisting diseases such as CHD, ins ofar as the CHD cases without DS developed brain tumors more frequently tha n expected. The ratio of acute lymphoblastic leukemia (ALL) to acute nonlym phoblastic leukemia (ANLL) was different among the malformations. The MR ca ses developed ANLL more frequently than expected, whereas the CPL cases dev eloped ALL more frequently. The distribution of the age at diagnosis for Wi lms' tumor was different according to the underlying malformation, Conclusi ons. Malformations might have some factors that inhibit or delay as well as promote the development of certain malignancies. (C) 2000 Wiley-Liss, Inc.