Pencil Beam Scanning Proton Therapy Demonstrates Long-Term Clinical Efficacy, Safety Among Children and Adolescents With Chordomas or Chondrosarcomas

Study results demonstrated that curative pencil beam scanning proton therapy demonstrated promising long-term efficacy and safety among children and adolescent/young adult patients with chordomas or chondrosarcomas. 

“Few studies have reported disease control and survival among [children and adolescent and young adults] after [proton therapy], reporting 5-year local control and overall survival rates of about 77%–85%, and 81%–86%, respectively,” stated Miriam Vazquez, MD, Paul Scherrer Institute, Zürich, Switzerland, and coauthors. “Here, we report long-term clinical outcomes.”

Researchers collected data from 76 children (n = 32) and adolescent or young adult (n = 44) patients with newly diagnosed (n = 66) or recurrent (n = 10) spinal (n = 16) or skull-based (n = 60) chordomas (n = 49) or chondrosarcomas (n = 27) who underwent a median dose of 73.8 Gy of curative pencil beam scanning proton therapy. Primary end points included local control rate, overall survival (OS) rate, and distant control rate. Key secondary end points included rate of grade ≥ 3 late toxicities, development of secondary tumors, and quality of life. 

At a median follow-up of 88.4 months, 9 patients experienced local failure, 2 patients experienced distant failure, and another 1.3% of patients experienced both local and distant failure. The 7-year OS rate was 86.3%, the 7-year local control rate was 87.7%, and the 7-year distant control rate was 95.7%. The 7-year distant control rate was 90% in children and 100% in adolescents and young adults (P = .049). The 7-year local control rate was 87.1% (P = .031) in patients who underwent surgical resection and 67.7% in patients who underwent biopsy (P = .031). Among patients with and without recurrent tumors, the 7-year OS rates were 44.6% and 94.5% (P < .001), the 7-year local control rates were 36.6% and 93.2% (P < .001), and the 7-year distant control rates were 77.6% and 98.3% (P = .003), respectively. The 7-year freedom from grade ≥ 3 late toxicity was 83.1%. Three children with chordomas developed secondary tumors. Quality of life measures did not differ from healthy controls 2 years following pencil beam scanning proton therapy. 

As Dr Vasquez et al concluded, “our encouraging survival and tumor control rates compare favorably with previous reports…support[ing] the safety of the treatment, especially in such a vulnerable population.”

Source:

Vazquez M, Cherchik A, de Angelis C, et al. Long-term clinical outcome and quality of life of children, adolescents, and young adults with chordoma or chondrosarcoma treated with pencil beam scanning proton therapy. Pediatr Blood Cancer. Published online: July 11, 2025. doi: 10.1002/pbc.31898