Table 5.

The Influence of the Analyzed Parameters on the 2-, 5- and 10-Year Relapse-Free Survival (RFS)

Parameter	Groups	2-Year RFS (%)	5-Year RFS (%)	10-Year RFS (%)	χ2 Test-Value	p-value
Age	19–49	72	72	62	2.280	0.516
	50–61	78	66	22
	62–70	64	45	29
	71–88	69	51	51
Gender	Female	69	53	45	1.105	0.269
	Male	69	66	47
WHO	0	88	85	75	17.941	<0.001
	1	58	45	31
	2	43	21	0
	3	0	0	0
Location	Parotid	67	61	40	0.789	0.430
	Submandibular	73	60	50
Clinical nerve palsy	Yes	53	50	23	2.592	0.009
	No	75	64	52
Radicality	R0	70	60	45	0.669	0.715
	R1	69	45	43
	R2	68	68	34
Nerve palsy after surgery	Yes	45	40	24	2.995	0.003
	No	78	55	52
Histopathological type	Squamous	55	46	0	6.525	0.258
	Adenocarcinoma	64	64	43
	Cystic adenoid carcinoma	76	59	59
	Undifferentiated	64	64	43
	Acinic	78	43	67
	Other	83	73	73
Neuroinvasion	Yes	55	50	27	2.268	0.023
	No	76	63	55
Angioinvasion	Yes	66	56	56	0.701	0.482
	No	70	63	43
Stage	I	100	88	88	17.724	<0.001
	II	80	75	56
	III	70	65	39
	IVab	67	34	23
T	1	95	83	83	20.922	<0.001
	2	77	73	61
	3	64	53	31
	4	43	50	0
N	Positive	46	36	24	3.117	0.002
	Negative	81	70	53
Time	<9 weeks	73	62	56	0.949	0.343
	≥9 weeks	65	57	29
Technique of RT	2D	44	30	30	4.928	0.085
	3D	70	70	46
	IMRT	76	60	45
Dose	<60Gy	44	28	14	3.489	<0.001
	≥60Gy	78	67	52
CHT	Yes	56	48	48	0.991	0.321
	No	71	62	44
Hemoglobin level	<12.5 mg/dL	43	43	N/A	1.212	0.225
	≥12.5 mg/dL	68	56	N/A
Tumor volume	≤10 cm3	95	83	83	9.956	0.019
	10.1–50 cm3	76	71	N/A
	50.1–100 cm3	70	56	0
	>100 cm3	44	44	N/A
Irradiation area	Only surgical bed with margin	83	68	55	13.555	0.004
	Surgical bed + lnd. group I-II	76	71	N/A
	Surgical bed + unilateral lnd.	74	70	42
	Surgical bed + bilateral lnd	38	19	19
Tumor bed volume (dose ≥ 60Gy)	≤100 cm3	93	93	78	6.204	0.102
	100.1–200 cm3	80	72	N/A
	200.1–300 cm3	67	59	N/A
	>300 cm3	50	50	0
Elective area volume (dose ≥ 50Gy)	≤ 150 cm3	88	85	56	7.205	0.125
	150.1–300 cm3	70	52	N/A
	300.1–450 cm3	60	N/A	N/A
	450.1–600 cm3	58	58	0
	>600 cm3	33	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.