Proton therapy delivered less radiation to surrounding organs while maintaining efficacy in children with neuroblastoma, according to study results.
“As survival rates improve for children with neuroblastoma, we need to reduce treatment-related long-term toxicities,” researcher Christine Hill-Kayser, MD, a radiation oncologist at Children’s Hospital of Philadelphia, said in a press release. “Proton beam therapy offers precise targeting with less radiation exposure to healthy tissue.”
Hill-Kayser and colleagues evaluated data from 13 children (median age, 3 years) with high-risk neuroblastoma. All children had responded well to chemotherapy, surgery and postoperative chemotherapy, as well as bone marrow transplantation. Some children also received immunotherapy.
Researchers assigned 11 of the children to proton therapy. The other two were chosen to receive 2,160 cGy of intensity-modulated X-ray (IMXT) therapy due to the locations of their tumors.
Five of the children received radiation to two or more tumor sites.
The median percentage of doses delivered to 95% clinical target volume were 99% for proton therapy and 100% for IMXT.
Local recurrence and clinical organ toxicity did not occur in any of the children after treatment, according to researchers.
Proton therapy spared the contralateral kidney in the nine patients with lateralized disease, researchers wrote. However, proton therapy did not reduce ipsilateral kidney dose.
Researchers reported improved overall bilateral renal sparing in the two children who received IMXT.
Overall, proton therapy reduced median doses to the bowel (33 cGy vs. 590 cGy; P=.01), total body (<1 cGy vs. 30 cGy; P=.15) and liver (<1 cGy vs. 529 cGy; P<.001). The heart and lung were less affected when chest radiation therapy was required, researchers wrote.
“To better assess the use of proton therapy against high-risk neuroblastoma, we’ll need to study larger numbers of patients and do long-term follow-up,” Hill-Kayser said. “However, this represents a great start.”
Disclosure: The researchers report no relevant financial disclosures.