title: Comparative analysis of extra-nodal NK/T-cell lymphoma and peripheral T-cell lymphoma: significant differences in clinical characteristics and prognosis.
abstract: OBJECTIVE
  We aimed to compare the frequencies, clinical characteristics, and prognostic factors of peripheral T-cell lymphoma (PTCL) vs. extra-nodal natural killer (NK)/T-cell lymphoma and to characterize the subtypes of extra-nodal NK/T-cell lymphoma.
  
  
  METHODS
  We reviewed 97 consecutive patients with PTCL and extra-nodal NKT lymphoma from 2000 to 2006. During this period, a total of 780 patients with malignant lymphomas were treated in our center. The diagnostic criteria used were based on the WHO classification system of malignant lymphomas.
  
  
  RESULTS
  Extra-nodal-NK/T-cell lymphoma and PTCL comprised 5.0% (39/780) and 7.4% (58/780) of all cases. Of the PTCL cases, histology was PTCL-NOS in 25, anaplastic large cell in 11, angioimmunoblastic T cell in 18 and other subtypes in four patients. Compared with PTCL, extra-nodal NK/T-cell lymphoma was associated with a significantly inferior rates of complete remission (33% vs. 53%, P = 0.05) and 3 yr overall survival (29.5% vs. 47.5%, P = 0.003). On multivariate analysis, extra-nodal NK/T-cell histology was independently associated with decreased survival. Further analysis into this subtype showed the nasal variant (n = 25) differed significantly from extra-nasal variant (n = 14) in terms of stage at presentation (stages III/IV, 36% vs. 79%), international prognostic index scores (high intermediate or high IPI scores, 24% vs. 64%), complete remission rates (48% vs. 7%), and median survival (10 months vs. 1 month, P < 0.0001).
  
  
  CONCLUSIONS
  Extra-nodal NK/T-cell lymphoma was associated with a poorer prognosis compared with PTCL and is likely to comprise two distinct variants with different clinical behavior and prognosis.
authors.affiliation: Department of Medical Oncology, National Cancer Centre, Singapore. soonthyelim@yahoo.com
authors.forename: Soon Thye
authors.initials: ST
authors.lastname: Lim
authors.forename: Siew Wan
authors.initials: SW
authors.lastname: Hee
authors.forename: Richard
authors.initials: R
authors.lastname: Quek
authors.forename: Lay Cheng
authors.initials: LC
authors.lastname: Lim
authors.forename: Swee Peng
authors.initials: SP
authors.lastname: Yap
authors.forename: Er-Li
authors.initials: EL
authors.lastname: Loong
authors.forename: Ivy
authors.initials: I
authors.lastname: Sng
authors.forename: Leonard Hwan-Cheong
authors.initials: LH
authors.lastname: Tan
authors.forename: Mei-Kim
authors.initials: MK
authors.lastname: Ang
authors.forename: Joanne
authors.initials: J
authors.lastname: Ngeow
authors.forename: Chee-Kian
authors.initials: CK
authors.lastname: Tham
authors.forename: Lynette
authors.initials: L
authors.lastname: Ngo
authors.forename: Min Han
authors.initials: MH
authors.lastname: Tan
authors.forename: Miriam
authors.initials: M
authors.lastname: Tao
mesh_terms: D017677:Age Distribution; D005260:Female; D006801:Humans; D007694:Killer Cells, Natural / Q000473:pathology*; D016399:Lymphoma, T-Cell / Q000453:epidemiology / Q000401:mortality / Q000473:pathology*; D016411:Lymphoma, T-Cell, Peripheral / Q000453:epidemiology / Q000401:mortality / Q000473:pathology*; D008297:Male; D009669:Nose Neoplasms / Q000401:mortality; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D015996:Survival Rate