Table 2. Cox univariate and multivariate analysis of prognostic factors in PTC patients.

Variable	Univariate analysis, P value		Multivariate analysis
			HR	95% CI	P value
Gender	0.118				–
Male
Female
Age, years	<0.05		2.00	1.17–3.42	<0.05
≤45					–
>45			2.00	1.17–3.42	<0.05
≤55					–
>55			2.76	1.70–4.50	<0.05
Family history	0.997				–
No
Thyroid cancer
Other malignant tumors
cN staging	<0.05		1.13	0.46–2.79	0.786
cN0
cN1
Tumor invasion	0.100				–
No
Yes
Multifocal	0.138				–
No
Yes
Bilateral	0.464				–
No
Yes
T staging	<0.05		1.02	0.83–1.27	0.827
T1
T2
T3
T4
Total thyroidectomy	0.317				–
Yes
No
Surgical residue	0.830				–
No
Yes
Lateral cervical lymph node dissection	<0.05		1.47	0.53–4.07	0.460
Yes
No
Extra-lymph node invasion	0.141
No
Yes					–
Maximum diameter of metastatic lymph nodes	<0.05		1.75	1.12–2.74	<0.05
No lymph node metastasis					–
<0.2 cm			1.05	0.19–5.82	0.959
0.2–3 cm			3.67	1.13–11.87	<0.05
>3 cm			5.20	1.31–20.65	<0.05
Unknown					–
Number of lymph node metastasis	<0.05		0.91	0.38–2.19	0.830
0
0–4
≥5
Unknown
Number of lymph node metastasis in central region	<0.05		1.11	0.65–1.90	0.694
0
0–4
≥5
Unknown
Number of lymph node metastasis in lateral region	<0.05		0.72	0.38–1.37	0.314
0
0–4
≥5
Unknown

The results were represented as hazard ratio (HR) and its 95% confidence interval (CI), where a P<0.05 was considered significant. Sub-variable analyses of age and maximum metastatic lymph node diameter were all based on the data of the first group respectively. PTC, papillary thyroid cancer.