Parents and siblings of children with cancer have between a two- and four-times increased risk of developing cancer than first-degree relatives with no childhood cancer patients, according to a study published in the International Journal of Cancer.1 The study, led by Joshua Schiffman, MD, Medical Director of the Huntsman Cancer Institute’s High Risk Pediatric Cancer Clinic, used data from the Utah Population Database to broadly examine the risk of all types of cancer in relatives of children with cancer.
The researchers examined the family medical history of 4,482 children age 18 or younger diagnosed with cancer over a 43-year period to determine the cancer risk in their relatives and compared the information to matched population controls.
The researchers found that first-degree relatives, primarily siblings, of pediatric cases faced a twofold increased risk of a cancer diagnosis before the age of 19, which extended to their second-degree relatives (P < 10-4, respectively). In addition, first-degree relatives of children diagnosed before the age of 5 had a 3.6-fold increased risk of developing pediatric cancer (P < 10-7), second-degree relatives of under age 5 cancer patients had a 2.5-fold risk (P < 10-4), and third-degree relatives were at a twofold risk (P < 10-3).
The researchers also assessed known inherited genetic syndromes in adult relatives of the pediatric cancer patients and found that cancers associated with Li-Fraumeni Syndrome appeared to be driving the increased risk to relatives 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% generally cited in adult hereditary cancers, and likely even more than 20%,” said Dr. Schiffman in a statement.
Collecting Family Medical Histories on Multiple Generations
Although childhood cancers are rare occurrences, the researchers recommend that physicians collect three generations of family medical history for all newly diagnosed pediatric cancer patients and refer family members with a history of early-onset cancers in children or adults for genetic counseling. In addition, parents of children diagnosed with cancer before the age of 5 with a family history of cancer should be told of the potential increased cancer risk to other children in the family. ■
Disclosure: The study authors reported no potential conflicts of interest.
1. Curtin K, Smith KR, Fraser A, et al: Familial risk of childhood cancer and tumors in the li-fraumeni spectrum in the utah population database: Implications for genetic evaluation in pediatric practice. Int J Cancer. June 12, 2013 (early release online).