title: [Localized Ewing sarcoma of the spine: a preliminary dose-escalation study comparing innovative radiation techniques in a single patient].
abstract: OBJECTIVE
  Although radiosensitive, spinal locations of Ewing's sarcomas are challenging for the radiation oncologist due to poor radiation tolerance of the spinal cord. However, some favorable anatomical compartments - that may represent more than 20% - were associated with a better outcome and could benefit from a radiation dose escalation using the most recent radiation therapy techniques.
  
  
  METHODS
  We performed a dose escalation study on one patient, declined in two scenarios: (1) a tumour located within a single vertebral body and (2) a locally advanced disease involving the vertebral foramen and paraspinal soft tissues. Five dose-levels are proposed: 44.8Gy, 54.4Gy, 59.2Gy, 65.6Gy and 70.4Gy (1.6Gy per session, 8Gy per week). The 3D-conformational technique is compared with static intensity modulated radiation therapy (IMRT), helical tomotherapy, volumetric modulated arc therapy (VMAT), stereotactic body robotic radiation therapy (SBRT) and protontherapy (passive scattering). Two constraints had to be respected in order to skip to the next level: the planned target volume (PTV) coverage must exceed 95% and the D(2%) on the spinal cord shall not exceed a given constraint set at 50Gy in case 1 and 44Gy in case 2 due to initial neurological sufferance.
  
  
  RESULTS
  Only protontherapy, SBRT, helical tomotherapy and VMAT appear able to reach the last dose level while respecting the constraints in case 1. On the other hand, only helical tomotherapy seems capable of reaching 59.2Gy on the PTV in case 2.
  
  
  CONCLUSIONS
  With the most recent radiation therapy techniques, it becomes possible to deliver up to 70.4Gy in a favorable compartment in this sham patient. Unfavorable compartments can receive up to 59.2Gy. Definitive radiation therapy may be an interesting local treatment option to be validated in an early phase trial.
authors: Département de radiothérapie, centre Alexis-Vautrin, avenue de Bourgogne, 54500 Vandœuvre-lès-Nancy, France. g.vogin@nancy.unicancer.fr
authors: G
authors: G
authors: Vogin
authors: M-C
authors: MC
authors: Biston
authors: V
authors: V
authors: Marchesi
authors: M
authors: M
authors: Amessis
authors: L
authors: L
authors: De Marzi
authors: F
authors: F
authors: Lacroix
authors: A
authors: A
authors: Leroy
authors: F
authors: F
authors: Gassa
authors: S
authors: S
authors: Zefkili
authors: S
authors: S
authors: Helfre
mesh_terms: D000293:Adolescent; D003131:Combined Modality Therapy; D019583:Dose Fractionation, Radiation; D006321:Heart / Q000528:radiation effects; D006801:Humans; D007668:Kidney / Q000528:radiation effects; D008168:Lung / Q000528:radiation effects; D008297:Male; D059351:Organ Sparing Treatments; D058958:Organs at Risk; D061766:Proton Therapy; D016634:Radiosurgery / Q000295:instrumentation / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D020266:Radiotherapy, Conformal / Q000295:instrumentation / Q000379:methods*; D011882:Radiotherapy, High-Energy / Q000379:methods; D050397:Radiotherapy, Intensity-Modulated / Q000295:instrumentation / Q000379:methods; D012371:Robotics; D012512:Sarcoma, Ewing / Q000188:drug therapy / Q000532:radiotherapy* / Q000601:surgery; D013116:Spinal Cord / Q000528:radiation effects; D013125:Spinal Neoplasms / Q000188:drug therapy / Q000532:radiotherapy* / Q000601:surgery; D013904:Thoracic Vertebrae / Q000601:surgery; D011522:Protons
chemical_list: D011522:Protons