title: Clinical implications of determination of safe surgical margins by using a combination of CT and 18FDG-positron emission tomography in soft tissue sarcoma.
abstract: BACKGROUND
  To determine safe surgical margins for soft tissue sarcoma, it is essential to perform a general evaluation of the extent of tumor, responses to auxiliary therapy, and other factors preoperatively using multiple types of diagnostic imaging. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) is a tool for diagnostic imaging that has recently spread rapidly in clinical use. At present, the roles played by FDG-PET/CT in determination of margins for surgical resection of sarcoma are unclear. The present study was undertaken to explore the roles of FDG-PET/CT in determination of surgical margins for soft tissue sarcoma and to examine whether PET can serve as a standard means for setting the margins of surgical resection during reduced surgery.
  
  
  METHODS
  The study involved 7 patients with sarcoma who underwent surgery in our department and in whom evaluation with FDG-PET/CT was possible. Sarcoma was histologically rated as MFH in 6 cases and leiomyosarcoma in 1 case. In all cases, sarcoma was superficial (T1a or T2a). The tumor border was defined by contrast-enhanced MRI, and SUVs were measured at intervals of 1 cm over a 5-cm long area from the tumor border. Mapping of viable tumor cells was carried out on whole-mount sections of resected tissue, and SUVs were compared with histopathological findings.
  
  
  RESULTS
  Preoperative maximum SUVs (SUV-max) of the tumor averaged 11.7 (range: 3.8-22.1). Mean SUV-max was 2.2 (range: 0.3-3.8) at 1 cm from the tumor border, 1.1 (0.85-1.47) at 2 cm, 0.83 (0.65-1.15) at 3 cm, 0.7 (0.42-0.95) at 4 cm, and 0.64 (0.45-0.82) at 5 cm. When resected tissue was mapped, tumor cells were absent in the areas where SUV-max was below 1.0.
  
  
  CONCLUSIONS
  Our findings suggest that a safe surgical margin free of viable tumor cells can be ensured if the SUV cut-off level is set at 1.0. FDG-PET/CT is promising as a diagnostic imaging technique for setting of safe minimal margins for surgical resection of soft tissue sarcoma.
authors.affiliation: Department of Orthopaedic Surgery, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan. masahiro@m3.kufm.kagoshima-u.ac.jp
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yokouchi
authors.forename: Mikio
authors.initials: M
authors.lastname: Terahara
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nagano
authors.forename: Yoshiya
authors.initials: Y
authors.lastname: Arishima
authors.forename: Michihisa
authors.initials: M
authors.lastname: Zemmyo
authors.forename: Takako
authors.initials: T
authors.lastname: Yoshioka
authors.forename: Akihide
authors.initials: A
authors.lastname: Tanimoto
authors.forename: Setsuro
authors.initials: S
authors.lastname: Komiya
mesh_terms: D000368:Aged; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007890:Leiomyosarcoma / Q000000981:diagnostic imaging / Q000601:surgery; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods; D049268:Positron-Emission Tomography / Q000379:methods*; D011237:Predictive Value of Tests; D011300:Preoperative Care / Q000379:methods*; D012509:Sarcoma / Q000000981:diagnostic imaging / Q000601:surgery*; D012983:Soft Tissue Neoplasms / Q000000981:diagnostic imaging / Q000601:surgery*; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D019788:Fluorodeoxyglucose F18