Comparative analysis of extra-nodal NK/T-cell lymphoma and peripheral T-cell lymphoma: significant differences in clinical characteristics and prognosis.
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.
Lim
Soon Thye
ST
Department of Medical Oncology, National Cancer Centre, Singapore. soonthyelim@yahoo.com
Hee
Siew Wan
SW
Quek
Richard
R
Lim
Lay Cheng
LC
Yap
Swee Peng
SP
Loong
Er-Li
EL
Sng
Ivy
I
Tan
Leonard Hwan-Cheong
LH
Ang
Mei-Kim
MK
Ngeow
Joanne
J
Tham
Chee-Kian
CK
Ngo
Lynette
L
Tan
Min Han
MH
Tao
Miriam
M
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