Table 1 Baseline characteristics of participants

Cases

271

368

191

191

Age at surgery

41 (21–54)

42 (25–50)

0.043

32 (24–50)

34 (21–51)

0.364

Female

188 (69.4%)

265 (72.0%)

0.468

103 (53.9%)

98 (51.3%)

0.608

Primary tumor

Right lobe

154 (56.8%)

222 (40.8%)

0.374

116 (60.7%)

109 (57.1%)

0.467

Multifocality

29 (10.7%)

41 (11.1%)

0.860

19 (9.9%)

21 (11.0%)

0.738

Nodule diameter (cm)

1.4 (1.0 – 3.4)

1.8 (1.0 – 4.0)

0.012

1.6 (1.0 – 3.5)

1.7 (1.1 – 4.0)

0.751

Contralateral nodule(s)

Multifocality

84 (31.0%)

150 (40.7%)

0.011

48 (25.1%)

51 (26.7%)

0.656

Nodule diameter

0.8 ± 0.7

1.0 ± 0.9

0.017

0.9 ± 0.8

1.0 ± 0.7

0.452

 ≥ 1.0 cm

57 (21.0%)

114 (31.0%)

57 (21.0%)

114 (31.0%)

0.726

Nodule volume (ml)

3.0 ± 2.9

3.4 ± 2.4

0.020

3.1 ± 2.6

3.3 ± 2.1

0.641

Pathological lymph node metastasis

80 (29.5%)

143 (38.9%)

0.014

62 (32.5%)

67 (35.1%)

0.589

Serum thyroglobulin

(normal: 1.59 – 50.03) (μg/ml) (one month after surgery)

21.77

(15.03 – 37.79)

0.07

(0.05–2.23)

0.247

22.81

(16.27 – 34.21)

0.41

(0..07 – 1.85)

0.127

Median follow-up period

4.1 years

(2.0–5.4)

4.7 years

(2.0–6.1)

0.024

4.1 years

(2.0–5.4)

4.2 years

(2.0–5.5)

0.172