Risk factors and outcomes of metastatic poorly differentiated thyroid carcinoma

Table 2 Risk factors associated with cancer-specific mortality in poorly differentiated thyroid carcinoma patients, n (%)

	Survival (n = 23)	Mortality (n = 16)	Univariate HR (95%CI)	P value	Multivariate HR (95%CI)1	P value
Age
< 45 years	11 (47.8)	3 (18.8)	Reference
≥ 45 years	12 (52.2)	13 (81.2)	3.47 (0.95–12.6)	0.060
Sex
Female	14 (60.9)	11 (68.8)	Reference
Male	9 (39.1)	5 (31.2)	1.58 (0.52–4.81)	0.416
Tumor size
≤ 2 cm	3 (13.0)	0	Reference
> 2-4 cm	7 (30.4)	8 (53.3)
> 4 cm	13 (56.5)	7 (46.7)	1.39 (0.62–3.12)	0.423
T stage
T1/T2	8 (34.8)	5 (31.2)	Reference
T3/T4	15 (65.2)	11 (68.8)	1.31 (0.44–3.85)	0.627
N stage
N0	23 (100)	12 (75.0)	Reference		Reference
N1	0	4 (25.0)	6.86 (1.82–25.8)	0.004	10.1 (2.34–43.3)	0.002
M stage
M0	17 (73.9)	1 (37.5)	Reference		Reference
M1	6 (26.1)	10 (62.5)
M2	0	5 (31.2)	2.96 (1.53–5.74)	0.001	2.41 (1.07–5.39)	0.033
Extrathyroidal invasion
No	14 (60.9)	7 (43.8)	Reference
Yes	9 (39.1)	9 (56.2)	1.64 (0.61–4.43)	0.329
Type of thyroid surgery
Total thyroidectomy	21 (91.3)	14 (87.5)	Reference
Lobectomy or subtotal thyroidectomy	2 (4.3)	2 (6.2)	3.48 (0.71–17.0)	0.124
131I cumulative dose
< 100 mCi	14 (60.9)	7 (43.8)	Reference
≥ 100 mCi	9 (39.1)	9 (56.2)	1.42 (0.52–3.83)	0.493
External beam radiation therapy
No	20 (87.0)	6 (37.5)	Reference		Reference
Yes	3 (13.0)	10 (62.5)	4.42 (1.50–13.0)	0.007	3.07 (0.86–11.0)	0.084

¹Adjusted for N stage, M stage, and external beam radiation therapy.