Table 4.

Univariate and multivariate Cox regression analyses of factors associated with cause-specific survival of patients with papillary thyroid carcinoma

	Univariate			Multivariate
	HR	95% CI	p values	HR	95% CI	p values
Male	5.19	1.04–25.83	0.0445
Age ≥60 years	15.5	1.81–132.7	0.0124	20.78	1.86–231.86	0.0137
Tumor >4 cm	3.84	0.77–19.03	0.0995
Ex2	12.1	1.41–103.4	0.0231	13.98	1.29–151.66	0.0301
cN1b	6.44	1.18–35.2	0.0315	5.18	0.88–33.55	0.0844
Ml	7.28	0.845–62.87	0.0709	9.42	0.60–148.37	0.1108
Aggressive type	5.57	1.12–27.7	0.0359
Ki-67 LI >10%	23.58	4.31–128.94	0.0003	34.08	3.81–305.16	0.0016
Ki-67 LI 5–10%	1.28	0.149–11.01	0.8210
Biochemically PD	NC	NC	NC	excluded
Tg-DT ≤2 years	NC	NC	NC	excluded

HR = Hazard ratio; CI = confidence interval; Ex2 = significant extrathyroid extension; Biochemically PD = biochemically persistent disease; Tg-DT = thyroglobulin doubling time. NC = Not calculated because all of the patients who died of the cancer had biochemically PD and Tg-DT <2 years. For the multivariate analysis, these two factors were excluded from the analysis.