Nodal failure patterns and utility of elective nodal irradiation in submandibular gland carcinoma treated with postoperative radiotherapy - a multicenter experience

Table 3 Univariate and multivariate analyses of adverse pathological factors

Univariate analysis		RC (%)		LC (%)		DMFS (%)		DFS (%)		OS (%)
Variable	N	5-year	P	5-year	P	5-year	P	5-year	P	5-year	P
N stage
pN+	18	49.6	0.002	75.0	0.015	31.1	< 0.001	24.5	< 0.001	37.5	< 0.001
pN0 & cN0/pNx^a	47	87.7		100		77.5		77.8		85.2
Extranodal extension
Yes	12	55.4	0.004	83.3	0.149	21.2	< 0.001	21.8	< 0.001	30.0	< 0.001
No	53	84.2		97.3		74.2		72.0		81.0
T stage
pT3–4	26	57.9	< 0.001	93.8	0.104	33.2	< 0.001	35.1	< 0.001	45.9	< 0.001
pT1–2	39	93.1		96.7		85.5		82.2		88.9
Lymphovascular invasion
Yes	15	51.0	< 0.001	90.0	0.569	29.6	< 0.001	30.5	< 0.001	44.4	< 0.001
No	50	89.4		96.9		78.6		75.0		82.7
Perineural invasion
Yes	35	66.2	0.007	92.0	0.084	48.9	0.002	45.7	0.001	66.3	0.092
No	30	95.7		100		87.9		87.9		78.0
Margin < 1 mm
Yes	47	79.1	0.910	96.6	0.794	68.7	0.418	66.0	0.449	75.7	0.475
No	18	80.9		91.7		57.0		57.5		61.1
High-grade histology
Yes	59	77.1	0.204	94.9	0.466	63.0	0.324	61.3	0.287	68.4	0.079
No	6	100		100		85.7		85.7		100
Multivariate analysis
Variable		HR	95% CI		P	Variable			HR	95% CI	P
Regional control						Disease-free survival
T stage (pT3–4 vs pT1–2)		8.129	1.661–39.779		0.010	N stage (pN+ vs pN0 & cN0/pNx^a)			4.026	1.464–11.075	0.007
Lymphovascular invasion (Yes vs No)		4.130	1.165–14.643		0.028	Perineural invasion (Yes vs No)			5.377	1.512–19.121	0.009
Local control		–	–		NS	T stage (pT3–4 vs pT1–2)			3.762	1.262–11.213	0.017
Distant metastasis-free survival						Overall survival
T stage (pT3–4 vs pT1–2)		5.171	1.715–15.591		0.004	N stage (pN+ vs pN0 & cN0/pNx^a)			4.363	1.710–11.127	0.002
Perineural invasion (Yes vs No)		4.337	1.234–15.236		0.022	T stage (pT3–4 vs pT1–2)			4.841	1.671–14.020	0.004
Lymphovascular invasion (Yes vs No)		2.719	1.065–6.942		0.037

Abbreviations: CI confidence interval, DFS disease free survival, DMFS distant metastasis free survival, HR Hazard ratio, LC local control, NS not statistically significant, OS overall survival, RC regional control
^a,no elective neck dissection in cN0 patients

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