Table 4.

Clinicopathological characteristics of PTC patients 55 or more years old based on tumor size. Data are presented as mean ± s.d. or as n (%). One-way ANOVA for numerical data followed by Bonferroni post hoc tests (P < 0.05 considered significant). Pairwise chi-square tests for discrete data, significance adjusted with Bonferroni correction (P < 0.0167 considered significant). Statistically significant P values are shown in bold.

	Tumor size, cm			P
	A: ≤1.0	B: <1.0 to ≤1.5	C: <1.5 to ≤2.0	A vs B	B vs C
	206 (77.4 %)	48 (18.0 %)	12 (4.5 %)
Age, years	60.7 ± 4.6	61.4 ± 4.9	60.8 ± 5.8	>0.999	>0.999
Sex				>0.999	0.692
Male	42 (20.4%)	9 (18.8%)	3 (25.0%)
Female	164 (79.6%)	39 (81.3%)	9 (75.0%)
Maximal tumor size (cm)	0.67 ± 0.18	1.21 ± 0.15	1.73 ± 0.16	<0.001	<0.001
Multifocality				>0.999	0.448
No	162 (78.6%)	38 (79.2%)	8 (66.7%)
Yes	44 (21.4%)	10 (20.8%)	4 (33.3%)
Minimal ETE				0.047	>0.999
No	133 (64.6%)	23 (47.9%)	6 (50.0%)
Yes	73 (35.4%)	25 (52.1%)	6 (50.0%)
Vascular invasion				0.014	0.066
No	190 (92.2%)	38 (79.2%)	6 (50.0%)
Yes	16 (7.8%)	10 (20.8%)	6 (50.0%)
Lymphatic invasion				0.062	0.508
No	161 (78.2%)	31 (64.6%)	6 (50.0%)
Yes	45 (21.8%)	17 (35.4%)	6 (50.0%)
Occult central LN metastasis				0.249	0.486
No	163 (79.1%)	34 (70.8%)	10 (83.3%)
Yes	43 (20.9%)	14 (29.2%)	2 (16.7%)
Metastatic LN ratio*	0.11 ± 0.23	0.18 ± 0.30	0.06 ± 0.16	0.411	0.589
Hashimoto or lymphocytic thyroiditis				0.370	0.317
No	152 (73.8%)	32 (66.7%)	10 (83.3%)
Yes	54 (26.2%)	16 (33.3%)	2 (16.7%)

*The metastatic LN ratio is calculated by dividing the number of metastatic LNs by the total number of LNs dissected.

ETE, extrathyroidal extension; LN, lymph node.