Kids of Childhood Cancer Survivors at No Greater Risk of Birth Defects

Childhood cancer survivors who plan on having children of their own can breathe a collective sigh of relief. In a recent report published in the Journal of Clinical Oncology, researchers concluded that the offspring of those who have undergone intensive, life-preserving cancer therapies as children are no more likely to have birth defects, such as Down syndrome, achondroplasia (a type of dwarfism) or cleft lip, than the general population.

While it has been known that treatments such as radiation and chemotherapy may result in future infertility as well as an increased risk of miscarriage, stillbirth or premature birth, a question has remained as to whether these oftentimes DNA-damaging therapies would increase the risk of congenital anomalies in a childhood cancer survivor’s offspring. Previous studies, although showing similar results, have been both small in size and lacking in detail.

The analysis looked at information culled from the Childhood Cancer Survivor Study, a large retrospective study of approximately 20,000 childhood cancer survivors diagnosed between 1970 and 1986. The analysis involved 4,699 children of 1,128 male and 1,627 female childhood cancer survivors who had been treated with radiotherapy to the pelvic region and DNA-damaging chemotherapy, including alkylating agents such as cyclophosphamide and ifosfamide. Of those studied, 129 children (or 2.7 percent) had at least one birth defect, which is consistent with the general population’s incidence of genetic anomalies—also roughly 3 percent.

Despite these positive findings, which are the strongest results to date regarding the children of childhood cancer survivors, researchers are continuing to sequence the DNA of both survivors and their children to determine genetic damage regardless of birth defects. More data is being gathered from U.S. and international trials on this issue, which will provide even more definitive results.