Table 2. Patient, treatment, and follow-up information.

Patient characteristic		No. (%)	No. of deaths	Survival times	Cumulative proportion of patients surviving after the indicated time			P	HR (95.0% CI)
				Median ± SE	Estimate ± SE
					1 year	3 years	5 years
Age	< 60	80 (47.1)	47	73.00 ± 11.30	0.88 ± 0.04	0.597 ± 0.055	0.49 ± 0.06
	≥ 60	90 (52.9)	53	30.00 ± 4.43	0.82 ± 0.04	0.574 ± 0.053	0.45 ± 0.06	1.161	0.78(1.72~0.46)
Differentiation	well differentiated	31 (18.2)	18	71.00 ± 28.29	0.87 ± 0.06	0.541 ± 0.091	0.50 ± 0.09	0.011*
	moderately differentiated	125 (73.5)	70	59.00 ± 10.13	0.87 ± 0.03	0.620 ± 0.044	0.49 ± 0.05	0.794	0.93(0.56 ~1.57)
	poorly differentiated	14 (8.2)	12	15.00 ± 9.35	0.57 ± 0.13	0.214 ± 0.110	0.21 ± 0.11	0.020*	2.40 (1.15~ 5.00)
Clinical stages	T1-T2	102 (60.0)	52	77.00 ± 10.62	0.91 ± 0.03	0.663 ± 0.047	0.59 ± 0.05
	T3-T4	68 (40.0)	48	32.00 ± 4.97	0.75 ± 0.05	0.437 ± 0.061	0.30 ± 0.06	0.000*	2.17(1.45 ~3.25)
	N0	116 (68.3)	61	71.00 ± 11.59	0.90 ± 0.03	0.670 ± 0.044	0.67 ± 0.04
	N1-N2	54 (31.8)	39	26.00 ± 6.08	0.74 ± 0.06	0.361 ± 0.067	0.30 ± 0.07	0.000*	2.39(1.58~3.62)
	I-II	73 (42.9)	30	98.00 ± 15.57	0.97 ± 0.02	0.763 ± 0.050	0.69 ± 0.06
	III-IV	97 (57.1)	70	32.00 ± 3.98	0.753 ± 0.04	0.429 ± 0.051	0.30 ± 0.05	0.000*	3.30 (2.10~5.18)
Treatment	Partial laryngectomy	104 (61.2)	50	73.00 ± 11.30	0.904 ± 0.03	0.678 ± 0.046	0.58 ± 0.05
	Total laryngectomy	66 (38.8)	50	30.00 ± 4.43	0.76 ± 0.05	0.405 ± 0.061	0.30 ± 0.06	0.000*	2.35 (1.58 ~3.49)
	cervical lymph node dissection	37 (21.8)	19		0.270 ± 0.06	0.47 ± 0.09	0.47 ± 0.09
	no cervical lymph node dissection	133 (78.2)	81	56.00 ± 10.04	0.89 ± 0.03	0.60 ± 0.04	0.48 ± 0.05	0.19	0.71(0.43 ~1.19)

Note:

^*P < 0.05.