title: Particle therapy using carbon ions or protons as a definitive therapy for patients with primary sacral chordoma.
abstract: OBJECTIVE
  This study retrospectively evaluated the efficacy and toxicity of particle therapy using carbon ions or protons for primary sacral chordomas.
  
  
  METHODS
  We evaluated 23 patients with primary sacral chordoma treated with carbon ion therapy (CIT) or proton therapy (PT) between July 2005 and June 2011 at the Hyogo Ion Beam Medical Center, Hyogo, Japan. The median patient age was 72 years. 14 patients were treated with 70.4 Gy equivalents (GyE) in 16 fractions and 9 were treated with 70.4 GyE in 32 fractions. CIT was used for 16 patients, and PT was used for 7 patients.
  
  
  RESULTS
  The median follow-up period was 38 months. At 3 years, local control (LC), overall survival (OS) and progression-free survival (PFS) for all patients were 94%, 83% and 68%, respectively. The log-rank test revealed that male sex was significantly related to better PFS (p=0.029). No other factors, including dose fractionation and ion type, were significant for LC, OS or PFS. In nine patients, ≥ Grade 3 acute dermatitis was observed, and ≥ Grade 3 late toxicities were observed in nine patients. The 32-fraction protocol reduced severe toxicities in both the acute and late phases compared with the 16-fraction protocol.
  
  
  CONCLUSIONS
  Particle therapy for patients with sacral chordoma showed favourable LC and OS. Severe toxicities were successfully reduced by modifying the dose fractionation and treatment planning in the later treatment era. Thus, this therapeutic modality should be considered useful and safe.
  
  
  CONCLUSIONS
  This is the first study including both CIT and PT for sacral chordomas.
authors.affiliation: Department of Radiology, Hyogo Ion Beam Medical Center, Tatsuno, Hyogo, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Mima
authors.forename: Y
authors.initials: Y
authors.lastname: Demizu
authors.forename: D
authors.initials: D
authors.lastname: Jin
authors.forename: N
authors.initials: N
authors.lastname: Hashimoto
authors.forename: M
authors.initials: M
authors.lastname: Takagi
authors.forename: K
authors.initials: K
authors.lastname: Terashima
authors.forename: O
authors.initials: O
authors.lastname: Fujii
authors.forename: Y
authors.initials: Y
authors.lastname: Niwa
authors.forename: T
authors.initials: T
authors.lastname: Akagi
authors.forename: T
authors.initials: T
authors.lastname: Daimon
authors.forename: Y
authors.initials: Y
authors.lastname: Hishikawa
authors.forename: M
authors.initials: M
authors.lastname: Abe
authors.forename: M
authors.initials: M
authors.lastname: Murakami
authors.forename: R
authors.initials: R
authors.lastname: Sasaki
authors.forename: N
authors.initials: N
authors.lastname: Fuwa
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002244:Carbon / Q000627:therapeutic use; D002817:Chordoma / Q000401:mortality / Q000556:secondary / Q000628:therapy*; D003872:Dermatitis / Q000209:etiology; D018572:Disease-Free Survival; D019583:Dose Fractionation, Radiation; D005260:Female; D005500:Follow-Up Studies; D063193:Heavy Ion Radiotherapy / Q000009:adverse effects / Q000379:methods*; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology; D061766:Proton Therapy; D011522:Protons / Q000009:adverse effects; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D012447:Sacrum; D012737:Sex Factors; D013125:Spinal Neoplasms / Q000401:mortality / Q000628:therapy*; D015996:Survival Rate
chemical_list: D011522:Protons; D002244:Carbon