title: Retroperitoneal sarcomas: patterns of care at diagnosis, prognostic factors and focus on main histological subtypes: a multicenter analysis of the French Sarcoma Group.
abstract: BACKGROUND
  Retroperitoneal sarcomas (RPS) are heterogeneous. No previous study has investigated the impact of specialized surgery, evaluated locoregional relapse (LRR), abdominal sarcomatosis and distant metastatic relapse as separate events, or considered histological subtypes separately. This study addresses these specific points in a homogeneous cohort of patients with completely resected primary RPS.
  
  
  METHODS
  We conducted a retrospective analysis of adult patients diagnosed with a RPS between 1 January 1988 and 31 December 2008 and eventually referred to one of 12 centers of the French Sarcoma Group. All cases were centrally reviewed by an expert pathologist.
  
  
  RESULTS
  Five hundred eighty-six patients were included. Median follow-up was 6.5 years [95% confidence interval (CI) 5.9-7.1]. Five hundred thirty-seven patients had localized disease and 389 patients (76%) had macroscopically complete resection of the tumor. In this latter group, the 5-year LRR-free survival rate was 46% [41-52] and the 5-year overall survival (OS) rate was 66% [61-71]. In multivariate analysis, gender, adjacent organ involvement, specialization of the surgeon, piecemeal resection and perioperative radiotherapy were independently associated with LRR. Specialization of the surgeon and piecemeal resection were independently associated with abdominal sarcomatosis whereas histology and adjacent organ involvement were independently associated with distant metastasis. Age, gender, grade, adjacent organ involvement and piecemeal resection were significantly associated with OS. Prognostic factors for LRR and OS were analyzed in well-differentiated and dedifferentiated liposarcomas and leiomyosarcomas. Grade 3 was an independent prognostic factor for OS of dedifferentiated liposarcomas.
  
  
  CONCLUSIONS
  This study underlines the crucial role of pretherapeutic assessment and meticulous histological examination of RPS as well as the need to consider histological subtypes separately. Surgery in a specialized center and avoidance of piecemeal resection stand out as the two most important prognostic factors for RPS and highlight the importance of treating these patients in specialized centers.
authors.affiliation: Department of Medical Oncology, Institut Bergonié, Bordeaux. Electronic address: m.toulmonde@bordeaux.unicancer.fr.
authors.forename: M
authors.initials: M
authors.lastname: Toulmonde
authors.affiliation: Department of Surgical Oncology, Institut Gustave Roussy, Villejuif.
authors.forename: S
authors.initials: S
authors.lastname: Bonvalot
authors.affiliation: Department of Surgical Oncology, Centre Léon Bérard, Lyon.
authors.forename: P
authors.initials: P
authors.lastname: Méeus
authors.affiliation: Department of Surgical Oncology, Institut Bergonié, Bordeaux.
authors.forename: E
authors.initials: E
authors.lastname: Stoeckle
authors.affiliation: Department of Radiation Oncology, Institut Régional du Cancer Montpellier, Montpellier.
authors.forename: O
authors.initials: O
authors.lastname: Riou
authors.affiliation: Department of Medical Oncology, Centre Georges François Leclerc, Dijon.
authors.forename: N
authors.initials: N
authors.lastname: Isambert
authors.affiliation: Department of Medical Oncology, Centre René Gauducheau, Nantes.
authors.forename: E
authors.initials: E
authors.lastname: Bompas
authors.affiliation: Department of Medical Oncology, Centre Oscar Lambret, Lille.
authors.forename: M
authors.initials: M
authors.lastname: Jafari
authors.affiliation: Department of Medical Oncology, Centre François Baclesse, Caen.
authors.forename: C
authors.initials: C
authors.lastname: Delcambre-Lair
authors.affiliation: Department of Medical Oncology, Centre Antoine Lacassagne, Nice.
authors.forename: E
authors.initials: E
authors.lastname: Saada
authors.affiliation: Departments of Medical Oncology.
authors.forename: A
authors.initials: A
authors.lastname: Le Cesne
authors.affiliation: Radiation Oncology, Institut Gustave Roussy, Villejuif.
authors.forename: C
authors.initials: C
authors.lastname: Le Péchoux
authors.affiliation: Department of Medical Oncology, Centre Léon Bérard, Lyon.
authors.forename: J Y
authors.initials: JY
authors.lastname: Blay
authors.affiliation: Department of Medical Oncology, Institut Curie, Paris.
authors.forename: S
authors.initials: S
authors.lastname: Piperno-Neumann
authors.affiliation: Department of Medical Oncology, Centre Claudius Regaud, Toulouse.
authors.forename: C
authors.initials: C
authors.lastname: Chevreau
authors.affiliation: Department of Medical Oncology, Centre Jean Perrin, Clermont-Ferrand.
authors.forename: J O
authors.initials: JO
authors.lastname: Bay
authors.affiliation: Department of Clinical and Epidemiological Research, Institut Bergonié, Bordeaux.
authors.forename: V
authors.initials: V
authors.lastname: Brouste
authors.affiliation: Department of Pathology, Institut Gustave Roussy, Villejuif.
authors.forename: P
authors.initials: P
authors.lastname: Terrier
authors.affiliation: Department of Pathology, Centre Léon Bérard, Lyon.
authors.forename: D
authors.initials: D
authors.lastname: Ranchère-Vince
authors.affiliation: Department of Pathology, Institut Bergonié, Bordeaux, France.
authors.forename: A
authors.initials: A
authors.lastname: Neuville
authors.affiliation: Department of Medical Oncology, Institut Bergonié, Bordeaux.
authors.forename: A
authors.initials: A
authors.lastname: Italiano
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018450:Disease Progression; D018572:Disease-Free Survival; D005260:Female; D005602:France; D006801:Humans; D007890:Leiomyosarcoma / Q000175:diagnosis / Q000401:mortality / Q000628:therapy; D008080:Liposarcoma / Q000175:diagnosis / Q000401:mortality / Q000628:therapy; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis / Q000473:pathology / Q000628:therapy; D009364:Neoplasm Recurrence, Local; D019990:Perioperative Care; D012186:Retroperitoneal Neoplasms / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery*; D012189:Retrospective Studies; D012509:Sarcoma / Q000401:mortality / Q000532:radiotherapy* / Q000601:surgery*; D015996:Survival Rate; D016896:Treatment Outcome; D055815:Young Adult
keywords: histology; prognosis; retroperitoneal sarcoma; surgery