Childhood Cancer Radiation Increases Risk of Stillbirth
Childhood cancer survivors continue to be affected by the treatment they received years afterward. The latest study of this long term effect reveals an increased risk of stillbirth and neonatal death by as much as 12 fold in women who received pelvic radiation as part of their childhood cancer treatment.
The study by Lisa B. Signorello, MD, from the International Epidemiology Institute in Rockville, Maryland, and the Vanderbilt-Ingram Cancer Center in Nashville, Tennessee and colleagues has been published online July 23 in the Lancet.
The researchers conducted a retrospective cohort analysis, within the Childhood Cancer Survivor Study (CCSS), of the risk of stillbirth and neonatal death among the offspring of men and women who had survived childhood cancer.
CCSS involves 25 institutions in the United States and 1 in Canada. All patients in CCSS were younger than 21 years at the initial diagnosis.
The study of 1148 men and 1657 women who survived childhood cancer. There were 4946 pregnancies among them. Only 28 of the 4946 pregnancies involved women given high doses of radiation to their pelvis. Of these, five resulted in stillbirths or early death.
The researchers found that irradiation of the male testes, the pituitary gland in either sex, and chemotherapy with alkylating drugs did not increase the risk of stillbirth or neonatal death.
Female childhood cancer survivors who received irradiation of the uterus and ovaries at doses greater than 10·00 Gy (five [18%] of 28, 9·1 [3·4—24·6]) were noted to have a significant increased risk of stillbirth or neonatal death.
This risk was even greater for girls treated before menarche. It took a much smaller dose of irradiation (as low as 1·00—2·49 Gy) of the uterus and ovaries to significantly increased the risk of stillbirth or neonatal death (three [4%] of 69, 4·7 [1·2—19·0]).
Women treated with radiation to the pelvic region after menarche had no significantly increased risk for stillbirths or neonatal deaths, compared with survivors who were not treated with radiation at all.
The researchers feel their findings do not support concern about heritable genetic changes affecting the risk of stillbirth and neonatal death in the offspring of men exposed to gonadal irradiation.
However, uterine and ovarian irradiation had serious adverse effects on the offspring that were probably related to uterine damage. Careful management is warranted of pregnancies in women given high doses of pelvic irradiation before puberty.
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Stillbirth and neonatal death in relation to radiation exposure before conception: a retrospective cohort study; Dr Lisa B Signorello ScD, Prof John J Mulvihill MD, Daniel M Green MD, Heather M Munro MS, Prof Marilyn Stovall PhD, Rita E Weathers BS, Prof Ann C Mertens PhD, John A Whitton MS, Leslie L Robison PhD, Prof John D Boice ScD;