Table 2.

The Influence of the Analyzed Parameters on the 2-, 5- and 10-Year Overall Survival (OS)

Parameter	Groups	2-Year OS (%)	5-Year OS (%)	10-Year OS (%)	χ2 Test-Value	p-value
Age	19–49	88	72	72	19.646	0.002
	50–61	78	75	13
	62–70	62	53	16
	71–88	44	23	23
Gender	Female	66	51	24	0.864	0.387
	Male	70	58	38
WHO	0	91	82	82	38.469	<0.001
	1	63	50	17
	2	28	6	0
	3	0	0	0
Location	Parotid	75	67	39	1.975	0.048
	Submandibular	63	45	24
Clinical Nerve palsy	Yes	39	27	19	3.797	<0.001
	No	79	66	34
Radicality	R0	75	60	33	8.200	0.017
	R1	64	56	35
	R2	45	24	12
Nerve palsy after surgery	Yes	43	27	17	4.114	<0.001
	No	80	68	33
Histopathological type	Squamous	41	32	0	13.646	0.018
	Adenocarcinoma	84	61	33
	Cystic adenoid carcinoma	77	70	35
	Undifferentiated	67	32	19
	Acinic	83	72	56
	Other	74	64	45
Neuroinvasion	Yes	50	34	20	3.248	0.001
	No	77	65	36
Angioinvasion	Yes	55	41	40	1.150	0.250
	No	70	57	31
Stage	I	94	94	51	23.219	<0.001
	II	85	74	44
	III	62	58	26
	IVab	52	29	25
T	1	96	96	51	30.977	<0.001
	2	81	67	42
	3	61	53	24
	4	42	19	19
N	positive	48	28	16	4.230	<0.001
	negative	79	69	40
Time	<9 weeks	76	65	42	2.295	0.022
	≥9 weeks	60	43	19
Technique of RT	2D	29	14	14	4.036	<0.001
	3D	69	59	34
	IMRT	83	67	31
Dose	<60Gy	35	26	9	26.350	<0.001
	≥60Gy	78	62	37
CHT	yes	72	60	30	0.880	0.929
	no	68	54	30
Hemoglobin level	<12.5 mg/dL	40	40	N/A	2.253	0.024
	≥12.5 mg/dL	83	72	N/A
Tumor volume	≤ 10 cm3	95	95	51	11.725	0.008
	10.1–50 cm3	85	65	N/A
	50.1–100 cm3	63	51	16
	>100 cm3	46	37	N/A
Irradiation area	Only surgical bed with margin	88	75	63	15.561	0.001
	Surgical bed + lnd. group I-II	78	63	39
	Surgical bed + unilateral lnd.	67	56	24
	Surgical bed + bilateral lnd	43	23	8
Tumor bed volume (dose ≥ 60Gy)	≤100 cm3	94	94	50	10.050	0.019
	100.1–200 cm3	84	65	39
	200.1–300 cm3	76	63	0
	>300 cm3	50	37	N/A
Elective area volume (dose ≥ 50Gy)	≤150 cm3	90	83	43	10.725	0.029
	150.1–300 cm3	65	46	0
	300.1–450 cm3	65	64	N/A
	450.1–600 cm3	62	33	0
	>600 cm3	67	33	N/A

Note: Statistically significant results in bold.

Abbreviations: p, significance level; R0, radical surgery; R1, non-radical microscopic surgery; R2, non-radical macroscopic surgery; RT, radiotherapy; CHT, chemotherapy; RT, radiotherapy; 2D, two-dimensional planning; 3D, three-dimensional planning; IMRT, planning with intensity-modulated radiation therapy