Table 1 Patient Demographics and Tumor Characteristics

Total tumor number

126

252

Tumor size (cm)

4.3 ± 1.8

3.8 ± 1.4

.003

Age at diagnosis (years)

47.6 ± 13.9

47.3 ± 12.3

.856

Symptoms

 Neck mass

72 (66.1)

137 (63.1)

.627

 Dysphagia

5 (4.6)

7 (3.2)

.544

 Tinnitus

1 (0.9)

6 (2.8)

.431

 Hoarseness

8 (7.3)

9 (4.1)

.290

 Horner syndrome

3 (2.8)

10 (4.6)

.555

 Tongue paralysis

11 (10.1)

18 (8.3)

.681

Tumor location

 Left-side

40

96

.193

 Right-side

52

100

.782

 Bilateral

17

28

.506

Shamblin classification

 I

16 (14.6)

41 (18.9)

.284

 II

43 (39.4)

81 (37.3)

.890

 III

50 (45.9)

95 (43.8)

.928

 SDHB gene screen

51 (46.8)

106 (48.8)

.726

 Mutation positive

12 (23.5)

9 (8.5)

.019

 Local invasion

27 (24.8)

51 (23.6)

.800