FRIDAY, Aug. 9 (HealthDay News) -- Close family members of children with cancer appear to have an increased risk of cancer themselves, a new study says.
Researchers examined the family medical history of nearly 4,500 children who were diagnosed with cancer over a 43-year period. They found that the parents, siblings and children of patients who were diagnosed with any kind of cancer up to age 18 had twice the risk of developing cancer compared to those in families with no childhood cancer patients.
And if a child was diagnosed with cancer at age 4 or younger, close relatives had a nearly fourfold increased risk of cancer, according to the study, which was recently published online in the International Journal of Cancer.
"No one had previously studied the question, so we simply told parents there was no evidence of increased risk to the other children. Now we can give an evidence-based answer -- the risk depends on your family history of cancer," study leader Dr. Joshua Schiffman, medical director of the High Risk Pediatric Cancer Clinic at the University of Utah's Huntsman Cancer Institute, said in a university news release.
Although the study tied cases of childhood cancer to higher cancer risk for family members, it did not establish a cause-and-effect relationship.
The researchers also examined known inherited genetic syndromes in adult relatives of pediatric cancer patients and found that cancers associated with Li-Fraumeni Syndrome (LFS) seemed to be a major factor in the increased cancer risk in families with a history of cancer.
"Not all children's cancers are hereditary. But the numbers in this study suggest that the proportion of hereditary childhood cancers may be significantly higher than the 5 to 10 percent generally cited in adult hereditary cancers, and likely even more than 20 percent," Schiffman said.
"LFS is one of the most devastating cancer syndromes," he noted. "It causes a variety of cancers in both children and adults. For people with LFS, the lifetime risk of getting cancer is 80 percent to 90 percent, but with increased and early screening for tumors, there's early indication of a very high survival rate, perhaps even approaching 100 percent. In a previous study, LFS patients who did not receive early screening only had a 20 percent survival rate."
The researchers said that doctors should collect three generations of family medical history for all newly diagnosed childhood cancer patients and that families with a history of early-onset cancers in children or adults should be referred for genetic counseling.
Parents who have a child diagnosed with cancer before age 5 and a family history of cancer should be told that their other children are at increased risk for cancer, the researchers say.
The Nemours Foundation has more about childhood cancer.