title: Intensity modulated radiotherapy (IMRT) in benign giant cell tumors--a single institution case series and a short review of the literature.
abstract: BACKGROUND
  Giant cell tumors are rare neoplasms, representing less than 5% of all bone tumors. The vast majority of giant cell tumors occurs in extremity sites and is treated by surgery alone. However, a small percentage occurs in pelvis, spine or skull bones, where complete resection is challenging. Radiation therapy seems to be an option in these patients, despite the lack of a generally accepted dose or fractionation concept. Here we present a series of five cases treated with high dose IMRT.
  
  
  METHODS
  From 2000 and 2006 a total of five patients with histologically proven benign giant cell tumors have been treated with IMRT in our institution. Two patients were male, three female, and median age was 30 years (range 20-60). The tumor was located in the sacral region in four and in the sphenoid sinus in one patient. All patients had measurable gross disease prior to radiotherapy with a median size of 9 cm. All patients were treated with IMRT to a median total dose of 64 Gy (range 57.6 Gy to 66 Gy) in conventional fractionation.
  
  
  RESULTS
  Median follow up was 46 months ranging from 30 to 107 months. Overall survival was 100%. One patient developed local disease progression three months after radiotherapy and needed extensive surgical salvage. The remaining four patients have been locally controlled, resulting in a local control rate of 80%. We found no substantial tumor shrinkage after radiotherapy but in two patients morphological signs of extensive tumor necrosis were present on MRI scans. Decline of pain and/or neurological symptoms were seen in all four locally controlled patients. The patient who needed surgical salvage showed markedly reduced pain but developed functional deficits of bladder, rectum and lower extremity due to surgery. No severe acute or late toxicities attributable to radiation therapy were observed so far.
  
  
  CONCLUSIONS
  IMRT is a feasible option in giant cells tumors not amendable to complete surgical removal. In our case series local control was achieved in four out of five patients with marked symptom relief in the majority of cases. No severe toxicity was observed.
authors.affiliation: Clinical Cooperation Unit Radiation Oncology, German Cancer Research Center, Heidelberg, Germany. Falk.Roeder@med.uni-heidelberg.de
authors.forename: Falk
authors.initials: F
authors.lastname: Roeder
authors.forename: Carmen
authors.initials: C
authors.lastname: Timke
authors.forename: Felix
authors.initials: F
authors.lastname: Zwicker
authors.forename: Christian
authors.initials: C
authors.lastname: Thieke
authors.forename: Marc
authors.initials: M
authors.lastname: Bischof
authors.forename: Jürgen
authors.initials: J
authors.lastname: Debus
authors.forename: Peter E
authors.initials: PE
authors.lastname: Huber
mesh_terms: D000328:Adult; D005260:Female; D018212:Giant Cell Tumor of Bone / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D050397:Radiotherapy, Intensity-Modulated; D055815:Young Adult