Table 3.

SEER^d cox proportional hazards analysis, by subtypes (HR^a (95% CI^b)).

Risk Factor	Well-Differentiated	Myxoid	Pleomorphic	Mixed	De-Differentiated	Round Cell
Age ≥ 35 (vs. <35)	3.42 (1.28–9.17)∗	3.34 (2.24–4.97)∗	0.84 (0.47–1.53)	1.48 (0.70–3.13)	1.68 (0.87–3.24)	2.12 (0.62–7.26)
Male (vs. Female)	1.34 (1.11–1.62)∗	1.12 (0.91–1.39)	1.12 (0.86–1.45)	0.87 (0.55–1.37)	0.99 (0.85–1.15)	1.01 (0.59–1.73)
Race
African American	0.92 (0.64–1.32)	1.18 (0.87–1.6)	1.42 (0.92–2.19)	0.96 (0.53–1.75)	0.73 (0.53–1.02)	1.62 (0.71–3.7)
Other	1.12 (0.82–1.54)	0.75 (0.47–1.19)	0.71 (0.43–1.18)	0.43 (0.10–1.79)	0.78 (0.6–1.01)	2.91 (1.27–6.67)
Caucasian	Reference	Reference	Reference	Reference	Reference	Reference
Metastatic Disease	3.16 (2.35–4.26)∗	4.41 (3.42–5.70)∗	2.79 (1.95–3.98)∗	2.53 (1.38–4.66)∗	2.87 (2.39–3.46)∗	9.03 (4.85–16.84)∗
Grade
II	2.22 (1.36–3.60)∗	0.98 (0.73–1.33)	0.58 (0.22–1.57)	0.33 (0.12–0.89)∗	1.26 (0.82–1.93)	3800.79 (0–3.535E+51)
III	5.50 (3.08–9.82)∗	1.95 (1.34–2.83)∗	0.92 (0.44–1.93)	1.42 (0.71–2.83)	1.82 (1.28–2.58)∗	6529.82 (0–6.061E+51)
IV	5.36 (2.65–10.84)∗	2.3 (1.62–3.28)∗	1.19 (0.58–2.47)	1.45 (0.73–2.86)	2.04 (1.44–2.88)∗	4963.68 (0–4.608E+51)
Unknown	1.08 (0.62–1.89)	1.28 (0.95–1.71)	0.97 (0.45–2.08)	1.30 (0.63–2.69)	1.82 (1.25–2.65)∗	4498.23 (0–4.178E+51)
I	Reference	Reference	Reference	Reference	Reference	Reference

∗ Significance defined as p < 0.01.

^dSurveillance, Epidemiology, and End Results Program Database.

^aHazard ratio.

^bConfidence interval.