Table 3.

Multivariate cox regression analyses: outcome of poorly differentiated thyroid carcinoma recurrence-free survival and overall survival.

Variable	Recurrence-free survival		Overall survival
	Hazard Ratio (95% CI)	p-value	Hazard Ratio (95% CI)	p-value
					Age at diagnosis (year)	1.084(1.053-1.117)	<0.001	1.075(1.036-1.114)	<0.001
Year of diagnosis (year)	1.034(0.942-1.135)	0.477	0.987(0.869-1.120)	0.835
Sex
Male	1		1
Female	1.160(0.649-2.075)	0.616	2.110(1.003-4.439)	0.049
Extrathyroidal extension
None	1		1
Yes	2.986(0.927-9.621)	0.067	8.088(1.825-35.844)	0.006
Multifocality
None	1		1
Yes	0,934(0.519-1.683)	0,820	1.724(0.864-3.439)	0.122
T stage (AJCC 8th)
T1	1		1
T2	1.100(0.318-3.807)	0.880	0.120(0.022-0.648)	0.014
T3	1.226(0.238-6.329)	0.808	0.504(0.074-3.430)	0.484
T4	3.446(1.352-8.784)	0.010	0.335(0.085-1.314)	0.117
N stage (AJCC 8th)
N0	1		1
N1	3.158(0.980-10.177)	0.054	1.492(0.354-6.291)	0.585
M stage (AJCC 8th)
M0	1		1
M1	2.646(1.486-4.7130	0.001	1.647(0.730-3.718)	0.229
Surgery
Biopsy or no surgery	1		1
Thyroidectomy only	0.207(0.106-0.405)	<0.001	0.416(0.173-0.999)	0.050
Thyroidectomy + lymph node dissection	0.242(0.118-0.498)	<0.001	0.333(0.129-0.860)	0.023
Radiation
None or refused	1		1
Radioactive iodine	0.192(0.067-0.547)	0.002	0.237(0.065-0.864)	0.029
External beam radiotherapy	0.780(0.423-1.438)	0.426	1.104(0.505-2.414)	0.804
Chemotherapy
None or unknown	1		1
Yes	1.069(0.556-2.055)	0.842	0.580(0.259-1.301)	0.186
Associated thyroid cancer
Papillary only	1		1
Follicular only	1.228(0.430-3.502)	0.701	0.400(0.110-1.450)	0.163
Other	2.496(1.059-5.883)	0.037	1.329(0.486-3.630)	0.579
None	1.750(0.705-4.343)	0.228	1.079(0.341-3.415)	0.897