Survivors of childhood cancer who receive mutagenic treatments, either drug based or radiologic, may be concerned about the risk of transmitting genetic damage to their children, but new findings should help reassure them as they plan for parenthood. A report from the Childhood Cancer Survivor Study (CCSS) provides strong evidence that children of cancer survivors aren't at increased risk for congenital anomalies as a result of a parent's treatment.

The large multicenter CCSS provided an opportunity to evaluate the risk of congenital anomalies in cancer survivors' offspring in relation to amounts of gonadal radiation and alkylating agents the parent received, something earlier studies couldn't achieve. Information on cancer treatments was abstracted from the records of 1,128 male and 1,627 female childhood cancer survivors. Information on pregnancy history and outcomes was obtained from self-report questionnaires and verified by medical experts and review of medical records. Of the 4,699 children of five-year cancer survivors included in the study, 129 (2.7%) had at least one congenital anomaly (defined as a cytogenic abnormality, single-gene defect, or congenital malformation). That rate is consistent with the rate in the general U.S. population. Among the children of mothers who were exposed to either radiation or alkylating agents, compared with women who received neither treatment, the prevalences of anomalies were 3% and 3.5%, respectively; among children of male survivors, the corresponding figures were 1.9% and 1.7%. When the treatments were examined separately, neither ovarian nor testicular radiation was associated with an elevated risk of anomalies in children, and no relationship was found between treatment with alkylating agents and an elevated risk of anomalies in children of male or female cancer survivors.

The findings strengthen the conclusions of earlier studies that have shown no increased risk of congenital anomalies in children of cancer survivors, although the authors note that "whether humans have the capacity to repair damage to germ cell DNA or whether the various processes of reproduction filter out such insults" (through infertility or miscarriage, for instance) is unknown. The results of the study, however, could be an important tool for nurses counseling survivors on their risk of transmitting genetic damage to their children.-Karen Rosenberg

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