title: Socioeconomic and demographic factors contributing to outcomes in patients with primary lymphoma of bone.
abstract: BACKGROUND
  Primary lymphoma of bone (PLB) is a rare disease, comprising a malignant lymphoid infiltrate of bone. The goal of this study was to identify socioeconomic, demographic, and anatomic factors as prognostic indicators of survival for this disease using the Surveillance, Epidemiology, and End Results (SEER) database.
  
  
  METHODS
  The SEER database was used to identify a study population of 692 patients diagnosed with PLB in the United States from 1989 to 2003. Survival was analyzed using the Kaplan-Meier method, with effects of potential prognostic factors on survival analyzed using the log-rank test. Multivariable analysis was performed by Cox proportional hazards regression.
  
  
  RESULTS
  The overall 5-year survival rate was 49.6%, with a 10-year survival rate of 30.2%. Median overall survival was 4.9 years (95% CI: 3.9, 6.1). In multivariable analysis, age (p<0.0001), marital status (p=0.006), and appendicular vs. axial tumor location (p=0.004) were found to be independent predictors of survival.
  
  
  CONCLUSIONS
  This population-based study of PLB identified age, marital status, and tumor location as independent indicators of prognosis. This finding supports the clinical suspicion that an appendicular tumor location confers a better prognosis than an axial tumor location.
authors.affiliation: Hofstra North Shore-LIJ School of Medicine, 500 Hofstra University, Hempstead, NY 11549, USA.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Jacobs
authors.affiliation: Department of Orthopaedics, North Shore Long Island Jewish Medical Center, 270-05 76th Avenue, New Hyde Park, NY 11040, USA.
authors.forename: Ryan
authors.initials: R
authors.lastname: Michels
authors.affiliation: Biostatistics Unit, Feinstein Institute for Medical Research, 350 Community Drive, Manhasset, NY 11030, USA.
authors.forename: Joanna
authors.initials: J
authors.lastname: Stein
authors.affiliation: Department of Orthopaedics, North Shore Long Island Jewish Medical Center, 270-05 76th Avenue, New Hyde Park, NY 11040, USA.
authors.forename: Adam S
authors.initials: AS
authors.lastname: Levin
keywords: Bone; Lymphoma; SEER; Socioeconomic