Defining Why Cancer Develops in Children
As new scientific discoveries deepen our understanding of how cancer develops in children, doctors and other healthcare providers face challenges in better using that knowledge to guide treatment and counsel families and patients. An oncologist offers expert commentary on a major study of cancer predisposition genes.
Together with that knowledge though come fresh challenges as to how to effectively better use that knowledge to structure treatment and counsel both patients and families. As more children continue to survive paediatric cancer, that counselling may very well have to extend into a patient’s adulthood and even into old age.
“More frequently than previously thought, children with cancer may have genes predisposing them to cancer, even when cancer doesn’t show up in the child’s family history,” said physician-researcher John M. Maris, M.D., a paediatric oncologist at The Children’s Hospital of Philadelphia (CHOP).
Maris’s editorial, “Defining Why Cancer Develops in Children,” in today’s New England Journal of Medicine, reflects on a major paediatric study of cancer predisposition genes in the same issue of the journal.
That study, by a team from St. Jude’s Research Hospital led by Dr James R. Downing, found that out of their sample group of 1120 patients, 8.5% of Children and Adolescents with Cancer had mutations known to raise their risk of cancer. Less than 50% of children who inherited those cancer predisposition genes had a family history of cancer.
Maris credits the new study as “the most comprehensive blueprint to date of genetic childhood-cancer predisposition,” in his editorial and adds that the full complexity of how children develop cancer remains to be investigated.
A child’s inherited cancer-predisposition mutation did not seem to lead to cancer in the parents or in other family member, in the majority of cases in the study. “We need to better understand how other genes may interact with the original mutation to cause cancer in the child,” Maris said.
Maris said that another implication is that, as gene sequencing tools and genetic science itself continue to advance, clinicians will need to better counsel family members on the implications of previously unrecognised cancer predisposition genes in their family. “For parents of a child with cancer, we will need to improve our efforts to provide evidence-based counselling as they plan whether to have another child. We may also consider offering genetic testing to a patient’s healthy siblings or other family members to better assess their possible risk of a future cancer.”
Because some cancer-related mutations may also increase the risk that a childhood-cancer survivor may later develop a second cancer, clinicians and cancer researchers will need to develop the most effective strategies for counselling patients “through the continuum of infancy to old age.”
“Like all good research, this new study opens up more questions and areas for more investigation,” said Maris. “At the very least, this work should remind clinicians that we need to look beyond family history in treating and counselling paediatric cancer patients and their families.”
“Defining Why Cancer Develops in Children,” New England Journal of Medicine, published online Nov. 18, 2015. http://doi.org/10.1056/NEJMe1513921