Women who take sex hormones before and during pregnancy are three times more likely to have children who develop cancer, according to researchers at Roswell Park Cancer Institute.
Epidemiologist Arthur Michalek, phd, associate director of the Department of Education, and colleagues report that neuroblastoma, the most common type of childhood cancer, is linked to a mother's use of sex hormones to increase fertility, control vaginal bleeding, or prevent miscarriages.
Neuroblastoma tumors are generally found in adrenal glands. Although cancer among young children is rare, neuroblastoma accounts for one-quarter of all childhood cancers and is diagnosed in about 500 children annually.
Previously, the low incidence rate of neuroblastomas prevented the detailed investigation of risk factors associated with this disease.
In the Roswell Park study, the first and largest of its kind, Dr. Michalek and associates compared the results of interviews with 183 women whose children were diagnosed with neuroblastoma and 372 women with healthy offspring. Those mothers who used sex hormones were more likely to have children who were later diagnosed with the disease.
Male children appeared to be at higher risk for the disease than females, with an average age at diagnosis of 18 months.
Women who took sex hormones to increase fertility proved to be at greatest risk. "The sizable numbers of case and control mothers interviewed [increased] the statistical power of this study and enabled the detection of subtle risk differences," explained Michalek.
Although not addressed in the study, the researchers suggest that other potential risk factors, such as the routine use of oral contraceptives, be examined in mothers of children diagnosed with neuroblastoma.
A Surprising Development
In a surprising development, vitamins used during pregnancy seemed to offer the unborn child some protection against cancer. The data, however, were based on a mother's self-reported use of vitamins, and this aspect of the investigation requires more controlled study, Michalek noted.