title: Improved Survival With Radiation Therapy in Stage I-II Primary Mediastinal B Cell Lymphoma: A Surveillance, Epidemiology, and End Results Database Analysis.
abstract: BACKGROUND
  Primary mediastinal B cell lymphoma (PMBCL) is an uncommon lymphoma for which trials are few with small patient numbers. The role of radiation therapy (RT) after standard immunochemotherapy for early-stage disease has never been studied prospectively. We used the Surveillance, Epidemiology, and End Results (SEER) database to evaluate PMBCL and the impact of RT on outcomes.
  
  
  METHODS
  We queried the SEER database for patients with stage I-II PMBCL diagnosed from 2001 to 2011. Retrievable data included age, gender, race (white/nonwhite), stage, extranodal disease, year of diagnosis, and use of RT as a component of definitive therapy. Kaplan-Meier overall survival (OS) estimates, univariate (UVA) log-rank and multivariate (MVA) Cox proportional hazards regression analyses were performed.
  
  
  RESULTS
  Two hundred fifty patients with stage I-II disease were identified, with a median follow-up time of 39 months (range, 3-125 months). The median age was 36 years (range, 18-89 years); 61% were female; 76% were white; 45% had stage I disease, 60% had extranodal disease, and 55% were given RT. The 5-year OS for the entire cohort was 86%. On UVA, OS was improved with RT (hazard ratio [HR] 0.446, P=.029) and decreased in association with nonwhite race (HR 2.70, P=.006). The 5-year OS was 79% (no RT) and 90% (RT). On MVA, white race and RT remained significantly associated with improved OS (P=.007 and .018, respectively). The use of RT decreased over time: 61% for the 67 patients whose disease was diagnosed from 2001 to 2005 and 53% in the 138 patients treated from 2006 to 2010.
  
  
  CONCLUSIONS
  This retrospective population-based analysis is the largest PMBCL dataset to date and demonstrates a significant survival benefit associated with RT. Nearly half of patients treated in the United States do not receive RT, and its use appears to be declining. In the absence of phase 3 data, the use of RT should be strongly considered for its survival benefit in early-stage disease.
authors.affiliation: Department of Radiation Oncology, University of Colorado Cancer Center, Aurora, Colorado. Electronic address: matthew.jackson@ucdenver.edu.
authors.forename: Matthew W
authors.initials: MW
authors.lastname: Jackson
authors.affiliation: Department of Radiation Oncology, University of Colorado Cancer Center, Aurora, Colorado.
authors.forename: Chad G
authors.initials: CG
authors.lastname: Rusthoven
authors.affiliation: Department of Radiation Oncology, University of Colorado Cancer Center, Aurora, Colorado.
authors.forename: Bernard L
authors.initials: BL
authors.lastname: Jones
authors.affiliation: Department of Medical Oncology, University of Colorado Cancer Center, Aurora, Colorado.
authors.forename: Manali
authors.initials: M
authors.lastname: Kamdar
authors.affiliation: Department of Radiation Oncology, University of Colorado Cancer Center, Aurora, Colorado.
authors.forename: Rachel
authors.initials: R
authors.lastname: Rabinovitch
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D016403:Lymphoma, Large B-Cell, Diffuse / Q000208:ethnology / Q000401:mortality* / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D008479:Mediastinal Neoplasms / Q000208:ethnology / Q000401:mortality* / Q000473:pathology / Q000532:radiotherapy*; D008875:Middle Aged; D016016:Proportional Hazards Models; D044469:Racial Groups; D011878:Radiotherapy / Q000706:statistics & numerical data; D018426:SEER Program; D016019:Survival Analysis; D013997:Time Factors; D014481:United States; D044465:White People / Q000706:statistics & numerical data; D055815:Young Adult