title: Carbon ion radiotherapy for unresectable retroperitoneal sarcomas.
abstract: OBJECTIVE
  To evaluate the applicability of carbon ion radiotherapy (CIRT) for unresectable retroperitoneal sarcomas with regard to normal tissue morbidity and local tumor control.
  
  
  METHODS
  From May 1997 to February 2006, 24 patients (17 male and 7 female) with unresectable retroperitoneal sarcoma received CIRT. Age ranged from 16 to 77 years (median, 48.6 years). Of the patients, 16 had primary disease and 8 recurrent disease. Histologic diagnoses were as follows: malignant fibrous histiocytoma in 6, liposarcoma in 3, malignant peripheral nerve sheath tumor in 3, Ewing/primitive neuroectodermal tumor (PNET) in 2, and miscellaneous in 10 patients. The histologic grades were as follows: Grade 3 in 15, Grade 2-3 in 2, Grade 2 in 3, and unknown in 4. Clinical target volumes ranged between 57 cm(3) and 1,194 cm(3) (median 525 cm(3)). The delivered carbon ion dose ranged from 52.8 to 73.6 GyE in 16 fixed fractions over 4 weeks.
  
  
  RESULTS
  The median follow-up was 36 months (range, 6-143 months). The overall survival rates at 2 and 5 years were 75% and 50%, respectively. The local control rates at 2 and 5 years were 77% and 69%. No complications of the gastrointestinal tract were encountered. No other toxicity greater than Grade 2 was observed.
  
  
  CONCLUSIONS
  Use of CIRT is suggested to be effective and safe for retroperitoneal sarcomas. The results obtained with CIRT were a good overall survival rate and local control, notwithstanding the fact that most patients were not eligible for surgical resection and had high-grade sarcomas.
authors.affiliation: Research Center Hospital for Charged Particle Therapy, National Institute of Radiological Sciences, Inage-ku, Chiba, Japan. s_itsuko@nirs.go.jp
authors.forename: Itsuko
authors.initials: I
authors.lastname: Serizawa
authors.forename: Kenji
authors.initials: K
authors.lastname: Kagei
authors.forename: Tadashi
authors.initials: T
authors.lastname: Kamada
authors.forename: Reiko
authors.initials: R
authors.lastname: Imai
authors.forename: Shinji
authors.initials: S
authors.lastname: Sugahara
authors.forename: Tohru
authors.initials: T
authors.lastname: Okada
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tsuji
authors.forename: Hisao
authors.initials: H
authors.lastname: Ito
authors.forename: Hirohiko
authors.initials: H
authors.lastname: Tsujii
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002244:Carbon; D002250:Carbon Radioisotopes / Q000627:therapeutic use*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D011855:Radiodermatitis / Q000473:pathology; D011879:Radiotherapy Dosage; D012062:Relative Biological Effectiveness; D012186:Retroperitoneal Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D012509:Sarcoma / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D012983:Soft Tissue Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D015996:Survival Rate; D014057:Tomography, X-Ray Computed; D047368:Tumor Burden; D055815:Young Adult
chemical_list: D002250:Carbon Radioisotopes; D002244:Carbon