Table 2 Subgroup analysis for OS and PFS in this meta-analysis

 Overall

6

2169

1.69 (1.36, 2.09)

< 0.001

40

0.14

 ≤ 0.2

3

1329

1.59 (0.91, 2.78)

0.110

71

0.03

 > 527.2

3

840

1.63 (1.19, 2.23)

0.002

0

0.48

 ≤ 327

3

825

1.87 (1.41, 2.49)

< 0.001

9

0.33

 > 327

3

1344

1.35 (0.79, 2.33)

0.270

60

0.08

 Radiotherapy +/− chemotherapy

3

987

1.54 (0.92, 2.59)

0.100

69

0.04

 IMRT

1

585

1.95 (1.26, 3.03)

0.003

-

-

 Radiotherapy +/− chemotherapy, chemotherapy, untreated

1

255

0.57 (0.08, 3.86)

0.570

-

-

 IMRT, CCRT +/− induction, and/ or adjuvant chemotherapy

1

342

1.43 (0.73, 2.81)

0.300

-

-

 Metastatic

2

660

1.22 (0.55, 2.74)

0.620

77

0.04

 Mixed

4

1509

1.89 (1.42, 2.52)

< 0.001

0

0.44

 Overall

4

1587

1.60 (1.29, 1.98)

< 0.001

0

0.56

 ≤ 432.48

2

1002

1.53 (1.14, 2.06)

0.005

47

0.17

 > 432.48

2

585

1.68 (1.24, 2.28)

< 0.001

0

0.90

 ≤ 342

2

585

1.68 (1.24, 2.28)

< 0.001

0

0.90

 > 342

2

1002

1.53 (1.14, 2.06)

0.005

47

0.17

 Radiotherapy +/− chemotherapy

3

1245

1.60 (1.29, 1.99)

< 0.001

4

0.35

 IMRT, CCRT +/− induction, and/ or adjuvant chemotherapy

1

342

1.59 (0.66, 3.84)

0.300

-

-

 Metastatic

2

660

1.53 (1.14, 2.04)

0.004

46

0.17

 Mixed

2

927

1.69 (1.24, 2.31)

< 0.001

0

0.56