Table 3 Baseline characteristics of patients with early recurrence, late recurrence and non-recurrence NPC

Age, N (%)

0.785

0.436

0.451

< 50 years old

1474 (52.85)

1322 (52.73)

68 (51.52)

84 (56.00)

≥ 50 years old

1315 (47.15)

1185 (47.27)

64 (48.48)

66 (44.00)

Gender, N (%)

0.069

0.003

0.409

Male

2020 (72.43)

1792 (71.48)

104 (78.79)

124 (82.67)

Female

769 (27.57)

715 (28.52)

28 (21.21)

26 (17.33)

T stage, N (%)

0.078

0.004

0.382

T0-1

533 (19.11)

491 (19.59)

20 (15.15)

22 (14.67)

T2

482 (17.28)

446 (17.79)

15 (11.36)

21 (14.00)

T3

1102 (39.51)

990 (39.49)

59 (44.70)

53 (35.33)

T4

672 (24.09)

580 (23.14)

38 (28.79)

54 (36.00)

N stage, N (%)

0.156

0.128

0.760

N0

212 (7.60)

202 (8.06)

4 (3.03)

6 (4.00)

N1

1105 (39.62)

999 (39.85)

53 (40.15)

53 (35.33)

N2

960 (34.42)

849 (33.87)

52 (39.39)

59 (39.33)

N3

512 (18.36)

457 (18.23)

23 (17.42)

32 (21.33)

Clinical stage, N (%)

0.452

0.004

0.314

Stage I

61 (2.19)

57 (2.27)

2 (1.52)

2 (1.33)

Stage II

363 (13.02)

339 (13.52)

12 (9.09)

12 (8.00)

Stage III

1251 (44.85)

1133 (45.19)

62 (46.97)

56 (37.33)

Stage IV

1114 (39.94)

978 (39.01)

56 (42.42)

80 (53.33)

EBV DNA_{pre−treatment}, N (%)

0.817

0.003

0.026

≤ 4000 copies/mL

1645 (58.98)

1494 (59.59)

80 (60.61)

71 (47.33)

> 4000 copies/mL

1144 (41.02)

1013 (40.41)

52 (39.39)

79 (52.67)

EBV DNA_pre−RT, N (%)

0.002

< 0.001

0.421

Undetectable

1341 (48.08)

1247 (49.74)

47 (35.61)

47 (31.33)

Detectable

1448 (51.92)

1260 (50.26)

85 (64.39)

103 (68.67)

EBV DNA_post−RT, N (%)

< 0.001

0.045

0.057

Undetectable

2367 (84.87)

2154 (85.92)

93 (70.45)

120 (80.00)

Detectable

422 (15.13)

353 (14.08)

39 (29.55)

30 (20.00)

Received inducing chemotherapy, N (%)

0.047

0.007

0.591

No

410 (14.70)

387 (15.44)

12 (9.09)

11 (7.33)

Yes

2379 (85.30)

2120 (84.56)

120 (90.91)

139 (92.67)

Received concurrent chemotherapy, N (%)

0.105

0.914

0.186

No

854 (30.62)

775 (30.91)

32 (24.24)

47 (31.33)

Yes

1935 (69.38)

1732 (69.09)

100 (75.76)

103 (68.67)

Received adjuvant chemotherapy, N (%)

0.125

0.205

0.823

No

2530 (90.71)

2283 (91.07)

115 (87.12)

132 (88.00)

Yes

259 (9.29)

224 (8.93)

17 (12.88)

18 (12.00)

Residue, N (%)

0.003

< 0.001

0.572

No

2227 (79.85)

2033 (81.09)

93 (70.45)

101 (67.33)

Yes

562 (20.15)

474 (18.91)

39 (29.55)

49 (32.67)