title: Low-dose whole brain radiotherapy with tumor bed boost after methotrexate-based chemotherapy for primary central nervous system lymphoma.
abstract: OBJECTIVE
  The purpose of this study is to evaluate the outcome of low-dose whole brain radiotherapy (WBRT) with tumor bed boost after methotrexate-based chemotherapy in the management of primary central nervous system lymphoma (PCNSL).
  
  
  METHODS
  We retrospectively analyzed 64 patients with pathologically proven PCNSL between 2000 and 2011. Methotrexate-based chemotherapy with a median of five cycles was followed by radiotherapy to the whole brain and to the initial tumor bed. The median dose to the whole brain and to the tumor bed was 27 Gy (range, 18 to 36 Gy) and 50.4 Gy (range, 45 to 54 Gy), respectively.
  
  
  RESULTS
  With a median follow-up period of 27 months, 55 patients (85.9%) achieved complete response (CR). The 5-year overall survival (OS) and progression-free survival (PFS) rates were 52.6% and 39.3%, respectively. In univariate analysis, factors associated with OS were age, performance status, involvement of deep structure, and CR to sequential chemoradiotherapy (CRT). These variables remained as significant factors for OS in multivariate analysis. CR to sequential CRT was the only positive factor associated with PFS (p=0.009). Neurologic toxicity was more common in elderly patients older than 60 years (p=0.025).
  
  
  CONCLUSIONS
  Low-dose WBRT with tumor bed boost after methotrexate-based chemotherapy might be an effective method for management of PCNSL.
authors.affiliation: Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Byoung Hyuck
authors.initials: BH
authors.lastname: Kim
authors.forename: Il Han
authors.initials: IH
authors.lastname: Kim
authors.forename: Sung-Hye
authors.initials: SH
authors.lastname: Park
authors.forename: Chul Kee
authors.initials: CK
authors.lastname: Park
authors.forename: Hee Won
authors.initials: HW
authors.lastname: Jung
authors.forename: Tae Min
authors.initials: TM
authors.lastname: Kim
authors.forename: Se-Hoon
authors.initials: SH
authors.lastname: Lee
authors.forename: Dae Seog
authors.initials: DS
authors.lastname: Heo