title: Prognostic factors predicting the postoperative survival period following treatment for primary retroperitoneal liposarcoma.
abstract: BACKGROUND
  Liposarcomas, which represent 20% of all adult sarcomas, are the most common histological type of malignant soft tissue tumors. The aim of this study was to define the prognostic factors that predict the postoperative survival period for patients with primary retroperitoneal liposarcoma.
  
  
  METHODS
  The clinical data and prognoses of 71 patients with primary retroperitoneal liposarcoma who were treated in the General Hospital of the People's Liberation Army of China between January 1, 2000 and December 31, 2007 were retrospectively reviewed and analyzed.
  
  
  RESULTS
  The primary tumor from each patient was resected; 54.9% (39/71) were deemed R0 resections, 31.0% (22/71) were R1 resections and 14.1% (10/71) were deemed R2 resections (palliative operations). The median follow up was 68 months (range: 1-160 months). Of the patients who received an R1 or R2 resection of their primary tumor, 96.7% (59/61) had tumor recurrence. The 1-year, 3-year, and 5-year recurrence-free rates were 77.0%, 29.8% and 19.7%, respectively. As of April 2013, 53 of the 71 patients had died from tumor recurrence. The overall 1-year, 3-year, 5-year, and 10-year survival rates were 88.7%, 76.1%, 61.7%, and 30.4%, respectively. The factors that were significantly associated with prognosis in the univariate analysis were age (as a categorical variable) (P = 0.006), modus operandi (P = 0.000), histologic subtype (P = 0.000), tumor grade (P = 0.000), ascites (P = 0.000), postoperative metastasis (P = 0.000) and adjuvant therapy (P = 0.030). However, in the multivariate analysis, the modus operandi (P = 0.000), tumor grade (P = 0.006), ascites (P = 0.027), postoperative metastasis (P = 0.023) and age (as a categorical variable) (P = 0.002) were the only significant predictors of survival.
  
  
  CONCLUSIONS
  Complete resection remains the most effective method for treating liposarcoma. High grade, old age (≥ 60 years old), postoperative metastasis, and ascites predict poor prognoses.
authors.forename: Xudong
authors.initials: X
authors.lastname: Zhao
authors.affiliation: Department of General Surgery, General Hospital of Chinese People's Liberation Army, Beijing 100853, China.
authors.forename: Peiyu
authors.initials: P
authors.lastname: Li
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Huang
authors.forename: Lin
authors.initials: L
authors.lastname: Chen
authors.forename: Na
authors.initials: N
authors.lastname: Liu
authors.forename: Yaoguang
authors.initials: Y
authors.lastname: She
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008080:Liposarcoma / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000601:surgery; D011379:Prognosis; D012186:Retroperitoneal Neoplasms / Q000601:surgery*; D012189:Retrospective Studies; D055815:Young Adult