3 things to know about radiation and children with cancer predisposition syndromes

Advancements in genetic testing and how genes can lead to cancer have expanded the possibilities for personalized treatments. Radiologists, caring for patients from screening through surveillance, must be aware of radiation sensitivity. Cancer predisposition syndromes (CPS), while rare, need to be considered when developing plans for imaging of children.

Janet Reid, MD, and Lisa States, MD, with the department of radiology at Children’s Hospital of Philadelphia, outlined special considerations for children with CPS in a piece in the September issue of the Journal of the American College of Radiology.

“Knowledge of specific syndromes associated with cancer may not be as important as understanding that the occurrence of cancer in children and young adults may be associated with increased risk for a second or multiple cancers and may be related to a genetic mutation associated with increased risk due to ionizing radiation,” Reid and States wrote.

Remain Aware: As the authors state, you don’t have to know every CPS when treating a child. But understanding such conditions require patients avoid radiation will improve care. Here are a few well-known CPS:

  • Li Fraumeni syndrome: This familial cancer syndrome presents a theoretical risk for increased sensitivity to ionizing radiation because cells are unable to repair damaged DNA.
  • Retinoblastoma: This hereditary condition increases risks for bone and soft tissue sarcoma both in and out of the radiation field.
  • Ataxia telangiectasia: This disorder is caused by a pathogenic variant of a mutated gene that impairs the cell’s ability to repair DNA and can lead to cell death or genomic instability.

Know the Risks: The authors cite a 2016 workshop by the Pediatric Cancer Working Group of the American Association for Cancer Research released surveillance guidelines for CPS with a minimal cancer risk of 5 percent. Currently, the estimate of pediatric cancer with germline mutation in a CPS is 10 percent. The group suggested using nonionizing radiation (ultrasound, MRI) instead of ionizing radiation (CT, nuclear medicine).

Look for Alternatives: Some CPS require whole-body screening with MRI (WBMRI), while liver lesions can be further examined with contrast-enhanced ultrasound (CEUS). The authors note the need for more research into these modalities by pediatric radiologists. And once a child is diagnosed with CPS, further imaging should only be done at a pediatric center.

“Surveillance imaging plays an important role in the life-time management of potential malignancy in these patients,” Reid and States wrote. “Early diagnosis will lead to less toxic therapy, including decreased radiation therapy, reduced future morbidity and improved outcomes.”