Table 1. Patient Characteristics.

Variables	Groups	n	%
Sex	Male	34	62
	Female	21	38
Age (yrs)	Median (range)	54 (24-81)
	≥60	17	32
	<60	38	68
Ann Arbor stage	I	39	71
	II	16	29
Performance status	ECOG 0, 1	52	94
	ECOG 2	3	6
Primary site	Sinonasal	47	86
	Others	8	14
Epstein-Barr virus	Yes	13	24
	Not checked	42	76
Serum LDH	Elevated	26	68
	Normal	12	32
B symptoms	Yes	13	24
	No	42	76
IPI	1 (low)	21	38
	2 (low intermediate)	28	51
	3 (high-intermediate)	6	11
	4 (high)	0	0
NKPI	Group 1	19	35
	Group 2	21	38
	Group 3	13	24
	Group 4	2	4

ECOG, Eastern Cooperative Oncology Group; IPI, international prognostic index; LDH, lactate dehydrogenase; NKPI, NK/T cell lymphoma prognostic index. ⁶