title: Treatment results of radiotherapy for malignant lymphoma of the orbit and histopathologic review according to the WHO classification.
abstract: OBJECTIVE
  To analyze the results of radiotherapy (RT) for malignant lymphoma of the orbit and to evaluate them compared with the World Health Organization (WHO) classification published in 2001.
  
  
  METHODS
  The data from 29 patients with malignant lymphoma of the orbit treated with RT at Gunma University Hospital between 1978 and 2001 were retrospectively analyzed. Pathologic slides from 23 cases were available and were reviewed by a hematopathologist according to the WHO classification. The original and reviewed diagnoses, patient characteristics, treatment results, and complications were analyzed. In principle, patients with low-grade or indolent lymphoma were treated with RT alone, using 30 Gy as the tumor dose. Survival data were calculated using the Kaplan-Meier method.
  
  
  RESULTS
  One case that proved to be a pseudotumor was excluded from evaluation. Of the 28 cases, 25 were Stage IAE, 1 was Stage IIAE, and 2 were Stage IVAE. The median follow-up was 71 months. According to the original classification and the Working Formulation, the 5- and 10-year overall survival rate of patients with low-grade lymphoma was 94% and 73%, respectively. The corresponding rates for those with intermediate-grade lymphoma were 67% and 67% (p = 0.15). In contrast, the WHO classification showed a significant difference in the survival curves. The 5- and 10-year overall survival rate of patients with mucosa-associated lymphoid tissue (MALT) lymphoma was 100% and 88%, respectively; for diffuse large B-cell patients, the rates were both 0% (p < 0.001). In patients with MALT lymphoma, one local and four distant relapses developed; two of them >10 years after initial treatment. All of the relapsed MALT lymphomas were controlled by salvage therapy.
  
  
  CONCLUSIONS
  Excellent local control and survival can be achieved for patients with orbital MALT lymphoma using RT alone. A precise histopathologic diagnosis using the WHO classification and long-term follow-up for >10 years is recommended.
authors.affiliation: Department of Radiology and Radiation Oncology, Gunma University School of Medicine, Maebashi, Japan. mhasegaw@med.gunma-u.ac.jp
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Hasegawa
authors.forename: Masaru
authors.initials: M
authors.lastname: Kojima
authors.forename: Mariko
authors.initials: M
authors.lastname: Shioya
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Tamaki
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Saitoh
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Sakurai
authors.forename: Yoshizumi
authors.initials: Y
authors.lastname: Kitamoto
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Hideo
authors.initials: H
authors.lastname: Niibe
authors.forename: Takashi
authors.initials: T
authors.lastname: Nakano
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008223:Lymphoma / Q000145:classification / Q000401:mortality / Q000473:pathology* / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging / Q000379:methods; D009918:Orbital Neoplasms / Q000145:classification / Q000401:mortality / Q000473:pathology* / Q000532:radiotherapy*; D012189:Retrospective Studies; D016019:Survival Analysis; D016896:Treatment Outcome; D014944:World Health Organization