Table 2.

Univariate 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)	1.039(1.017-1.061)	<0.001	1.031(1.006-1.057)	0.014
Year of diagnosis (year)	0.962(0.894-1.036)	0.305	0.934(0.850-1.026)	0.153
Sex
Male	1		1
Female	0.875(0.525-1.458)	0.608	1.188(0.634-2.227)	0.591
Extrathyroidal extension
None	1		1
Yes	2.758(1.087-6.997)	0.033	3.662(1.100-12.187)	0.034
Multifocality
None	1		1
Yes	0.895(0.528-1.518)	0.681	1.235(0.657-2.319)	0.512
T stage (AJCC 8th)
T1	1		1
T2	1.599(0.577-4.427)	0.367	0.955(0.272-3.353)	0.943
T3	0.993(0.254-3.885)	0.992	0.933(0.219-3.974)	0.925
T4	3.601(1.583-8.191)	0.002	1.181(0.395-3.526)	0.766
N stage (AJCC 8th)
N0	1		1
N1	3.751(1.358-10.358)	0.011	2.230(0.657-7.566)	0.198
M stage (AJCC 8th)
M0	1		1
M1	2.197(1.277-3.780)	0.004	1.739(0.834-3.623)	0.140
Surgery
Biopsy or no surgery	1		1
Thyroidectomy only	0.302(0.161-0.567)	<0.001	0.579(0.275-1.215)	0.148
Thyroidectomy + lymph node dissection	0.493(0.262-0.928)	0.028	0.692(0.309-1.550)	0.371
Radiation
None or refused	1		1
Radioactive iodine	0.232(0.103-0.523)	<0.001	0.487(0.186-1.273)	0.142
External beam radiotherapy	0.706(0.404-1.235)	0.223	0.845(0.437-1.633)	0.617
Chemotherapy
None or unknown	1		1
Yes	1.255(0.694-2.269)	0.452	0.670(0.333-1.345)	0.260
Associated thyroid cancer
Papillary only	1		1
Follicular only	0.767(0.301-1.954)	0.579	0.317(0.099-1.012)	0.052
Other	1.860(0.886-3.903)	0.101	1.076(0.460-2.516)	0.865
None	1.500(0.699-3.219)	0.298	0.820(0.624-2.076)	0.676