Pencil beam scanned protons for the treatment of patients with Ewing sarcoma

Pediatr Blood Cancer. 2017 Dec;64(12). doi: 10.1002/pbc.26688. Epub 2017 Jun 19.


Background: Few data exist regarding the clinical outcome of patients with Ewing sarcoma (EWS) treated with pencil beam scanning proton therapy (PT). We report the outcome of children, adolescents and young adults (AYA) treated with PT at the Paul Scherrer Institute.

Materials: Thirty-eight patients (median age, 9.9 years) received a median dose of 54.9 Gy(RBE) (where RBE is relative biologic effectiveness). Size of the tumor ranged from 1.7 to 24 cm. Most common primary site was axial/pelvic (n = 27; 71%). Four patients (11%) presented with metastases at diagnosis. Twenty (53%) patients had chemo-PT only. Median follow-up was 49.6 months (range, 9.2-131.7).

Results: The 5-year actuarial rate of local control (LC), distant metastasis-free survival (DMFS), and overall survival (OS) were 81.5%, 76.4%, and 83.0%, respectively. All local recurrences occurred in field and in patients with nonextremity primaries. Six patients died, all of tumor progression. Age < 10 years was a favorable factor of borderline significance for LC (P = 0.05) and OS (P = 0.05), but was significant for DMFS (P = 0.003). Tumor volume <200 ml was a significant prognostic factors for DMFS (P = 0.03), but not for OS (P = 0.07). Metastasis at diagnosis was a strong predictor of local failure (P = 0.003). Only two grade 3 late toxicities were observed. The 5-year actuarial rate of grade 3 toxicity-free survival was 90.9%.

Conclusions: These preliminary data suggest that the outcomes of children and AYA with EWS are good and PT was well tolerated with few late adverse events. The local and distant tumor control for older patients with large pre-PT tumor volumes remains problematic.

Keywords: AYA; Ewing sarcoma; children; late toxicity; local tumor control; pencil beam scanned protons; proton therapy.

MeSH terms

  • Adolescent
  • Adult
  • Bone Neoplasms / mortality
  • Bone Neoplasms / pathology
  • Bone Neoplasms / radiotherapy*
  • Child
  • Child, Preschool
  • Female
  • Humans
  • Infant
  • Male
  • Proton Therapy*
  • Sarcoma, Ewing / mortality
  • Sarcoma, Ewing / pathology
  • Sarcoma, Ewing / radiotherapy*
  • Tumor Burden
  • Young Adult