Table 6.

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

Parameter	Groups	2-Year LRFS(%)	5-Year LRFS(%)	10-Year LRFS(%)	χ2 Test-Value	p-value
Age	19–49	90	90	77	6.963	0.073
	50–61	85	85	28
	62–70	73	55	37
	71–88	73	49	49
Gender	Female	80	67	58	0.870	0.384
	Male	82	79	55
WHO	0	96	96	85	19.689	0.002
	1	74	63	43
	2	58	19	0
	3	0	0	0
Location	Parotid	81	73	41	0.616	0.538
	Submandibular	81	74	62
Clinical nerve palsy	Yes	74	67	33	1.610	0.107
	No	84	75	61
Radicality	R0	84	73	55	0.662	0.718
	R1	82	73	58
	R2	68	68	34
Nerve palsy after surgery	Yes	83	74	58	1.081	0.279
	No	76	69	42
Histopathological type	Squamous	61	51	0	11.104	0.049
	Adenocarcinoma	83	66	33
	Cystic adenoid carcinoma	95	95	95
	Undifferentiated	64	64	43
	Acinic	91	73	55
	Other	88	81	81
Neuroinvasion	Yes	82	73	64	0.924	0.355
	No	79	74	39
Angioinvasion	Yes	77	66	66	0.756	0.449
	No	82	74	52
Stage	I	100	100	100	10.256	0.017
	II	87	77	58
	III	79	73	43
	IVab	70	59	39
T	1	95	95	95	12.233	0.007
	2	89	77	66
	3	73	59	35
	4	72	60	0
N	Positive	69	61	40	1.684	0.092
	Negative	86	78	59
Time	<9 weeks	83	78	71	1.247	0.213
	≥9 weeks	79	66	34
Technique of RT	2D	53	35	35	7.141	0.028
	3D	89	89	59
	IMRT	85	74	56
Dose	<60Gy	64	52	26	2.653	0.008
	≥60Gy	86	78	60
CHT	Yes	66	57	57	1.202	0.229
	No	84	76	54
Hemoglobin level	<12.5 mg/dL	67	67	N/A	0.021	0.983
	≥12.5 mg/dL	75	59	N/A
Tumor volume	≤10 cm3	95	95	95	5.129	0.162
	10.1–50 cm3	86	74	N/A
	50.1–100 cm3	81	73	0
	>100 cm3	78	78	N/A
Irradiation area	Only surgical bed with margin	91	76	61	5.129	0.163
	Surgical bed + lnd.group I-II	88	78	N/A
	Surgical bed + unilateral lnd.	81	77	5
	Surgical bed + bilateral lnd	61	61	61
Tumor bed volume (dose ≥ 60Gy)	≤ 100cm3	94	94	94	5.543	0.136
	100.1–200 cm3	83	83	N/A
	200.1–300 cm3	73	64	N/A
	>300 cm3	77	77	0
Elective area volume (dose ≥ 50Gy)	≤150 cm3	94	88	63	8.759	0.067
	150.1–300 cm3	80	70	N/A
	300.1–450 cm3	75	N/A	N/A
	450.1–600 cm3	58	58	0
	>600 cm3	100	100	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.