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Worth Attention pediatric Protons

Proton use reached nearly 40% in recent Children’s Oncology Group radiotherapy trials

Across 27 years of COG trials, IMRT/VMAT replaced 3D photons while proton use expanded to nearly 40% of radiotherapy patients.

RadOncToday · ·1 min read

KEY POINTS

  • Investigators queried the IROC database for Children’s Oncology Group trials with at least one patient receiving radiotherapy from 1998–2025. The analysis covered 83 trials, 8,898 patients, 751 institutions and seven countries, including 7,881 patients from the United States and 1,017 internationally.
  • Median age at enrollment was 9 years overall and with photon RT versus 7 years among proton-treated patients. CNS and rhabdomyosarcoma/soft-tissue-sarcoma protocols dominated enrollment, accounting for 35 trials/3,213 patients and 16 trials/2,126 patients, respectively.
  • Proton therapy moved from uncommon to mainstream within pediatric cooperative-group RT. Forty-eight of 83 trials included at least one proton-treated patient; proton use increased from approximately 2% before 2000 to nearly 40% in 2021, averaging 38.5% of radiotherapy patients from 2021 onward.
  • CNS and rhabdomyosarcoma trials were among the earliest and largest adopters. Across the full study period, 361 CNS and 248 rhabdomyosarcoma patients received protons; recent use in these disease groups commonly ranged from 20–50%, reaching 88% in rhabdomyosarcoma trial patients in 2025.
  • Photon technology changed just as dramatically. 3D-conformal use fell from approximately 73% in 1998 to 15% in 2025, while IMRT/VMAT increased from 26% to 89%. The two curves crossed in 2012, after which IMRT/VMAT became the dominant photon technique.
  • Proton adoption tracked geographic infrastructure. Early proton enrollment was concentrated in Massachusetts and California; later, Texas, Florida and Tennessee became major contributors as the number of treatment facilities expanded in those states.
  • Central IROC review classified >90% of evaluable treatments as appropriate or acceptable deviations across modalities in both US and international cohorts. The dataset, however, describes technology adoption and protocol compliance—not whether one modality produced superior disease control, toxicity, neurocognition or survivorship.

CLINICAL TAKEAWAY

Pediatric cooperative-group radiotherapy has undergone two simultaneous transitions: 3D photons → IMRT/VMAT and conventional photons → increasing proton use. The next question is no longer whether these technologies can be incorporated into pediatric trials, but whether their adoption produces measurable reductions in late toxicity and survivorship burden.

SOURCE

International Journal of Radiation Oncology, Biology, Physics