Kids of childhood cancer survivors are not at an increased risk for birth defects stemming from their parents' exposure to chemotherapy or radiation, a new study has revealed. Childhood cancer survivors'' exposure to chemotherapy, radiation does not increase risk of birth defects in their children
The findings provide reassurance that increased risks of birth defects are unlikely for cancer survivors who are concerned about the potential effects of their treatment on their children, and can help guide family planning choices.
"We hope this study will become part of the arsenal of information used by the physicians of childhood cancer survivors if reproductive worries arise," said lead author Lisa Signorello, Sc.D., associate professor of medicine at Vanderbilt University in Nashville, TN, and senior epidemiologist at the International Epidemiology Institute in Rockville, MD.
"Childhood cancer survivors face real reproductive concerns, including unknowns related to the effects of therapy. But, hopefully this study will provide some reassurance that their children are unlikely to be at increased risk for genetic defects stemming from their earlier treatment."
According to Signorello, childhood cancer patients frequently receive aggressive, though life-saving, radiation and chemotherapy treatments that can affect their ability to have children.
For girls, radiation to the pelvis - and the resulting damage to the uterus - has been associated with a risk for pregnancy outcomes such as miscarriage and preterm birth, and effects on the ovaries can lead to infertility. Radiotherapy and chemotherapy with alkylating agents (e.g., busulphan, cyclophosphamide and dacarbazine) are DNA-damaging treatments, affecting both cancer and healthy cells.
In the current study, investigators used information from the Childhood Cancer Survivor Study, a large retrospective study of treatment and outcomes in more than 20,000 childhood cancer survivors diagnosed between 1970 and 1986. Signorello and her colleagues examined data from 4,699 children of 1,128 men and 1,627 women who were 5-year childhood cancer survivors.
The survivors reported their children's health problems through questionnaires, and investigators also examined medical records from survivors and their children, focusing on survivors' history of radiation to the testes or ovaries and chemotherapy with alkylating agents.
Of the survivors, 63 percent (1,736) had received radiation for their cancer as children, and 44 percent of men (496) and 50 percent of women (810) had received chemotherapy with alkylating agents.
Overall, 2.7 percent (129) of the survivors'' children had at least one birth defect, such as Down syndrome, achondroplasia or cleft lip. Researchers found that 3 percent of children of mothers exposed to radiation or treated with alkylating chemotherapy agents had a genetic birth defect, compared to 3.5 percent of children of mothers who were cancer survivors but did not have such exposures.
Only 1.9 percent of children of male cancer survivors who received these DNA-damaging treatments had such birth defects, compared to 1.7 percent of children of male survivors who did not have this type of chemotherapy or radiation.