Table 3.

Multivariate results from Cox's regression for the endpoints: local control (LC), locoregional control (LRC), disease-free survival (DFS) and overall survival (OS). Gender (male) was excluded from multivariate analysis owing to poor estimation. Dose per fraction and overall treatment time were also excluded owing to high correlation with mean dose converted to 2 Gy in the primary tumour (D_mean).

Variables	HR	95% CI	p-value
LC
Age	1.00	(0.96; 1.05)	0.88
Tumour site
Hypo + Ph/la + Lar	1	–	–
Oral cavity	3.05	(0.51; 18.13)	0.22
Oropharynx	0.70	(0.20; 2.53)	0.59
Nasopharynx	0.29	(0.05; 1.58)	0.15
T stage (3–4)	2.81	(0.80; 9.87)	0.11
N stage (2–3)	0.96	(0.29; 3.23)	0.95
Non-concomitant RT	3.70	(1.09;12.50)	0.04
Dmean (≥70 Gy)	1.14	[0.39; 3.31]	0.82
LRC
Age	1.02	[0.98; 1.06]	0.43
Tumour site
Hypo + Ph/la + Lar	1	--	--
Oral cavity	2.56	[0.45; 14.39]	0.29
Oropharynx	0.57	[0.18; 1.78]	0.33
Nasopharynx	0.34	[0.08; 1.41]	0.14
T stage (3–4)	2.47	[0.83; 7.35]	0.10
N stage (2–3)	0.88	[0.30; 2.60]	0.82
Non-concomitant RT	4.78	[1.61;14.13]	0.005
Dmean (≥70 Gy)	1.18	[0.46; 3.04]	0.73
DFS
Age	1.00	[0.97; 1.03]	0.80
Tumour site
Hypo + Ph/la + Lar	1	–	–
Oral cavity	1.21	[0.34; 4.34]	0.77
Oropharynx	0.55	[0.26; 1.13]	0.10
Nasopharynx	0.28	[0.11; 0.69]	0.006
T stage (3–4)	1.29	[0.67; 2.48]	0.45
N stage (2–3)	0.88	[0.44; 1.76]	0.72
Non-concomitant RT	2.00	[1.03; 3.86]	0.04
Dmean (≥70 Gy)	0.95	[0.51; 1.79]	0.88
OS
Age	1.02	[0.99; 1.05]	0.15
Gender (male)	0.64	[0.25; 1.64]	0.36
Tumour site
Hypo + Ph/la + Lar	1	–	–
Oral cavity	1.92	[0.80; 4.64]	0.15
Oropharynx	0.97	[0.46; 2.06]	0.94
Nasopharynx	0.24	[0.08; 0.72]	0.01
T stage (3–4)	2.07	[1.01; 4.27]	0.048
N stage (2–1)	2.12	[0.89; 5.02]	0.09
Non-concomitant RT	0.75	[0.36; 1.55]	0.43
Dmean (≥70 Gy)	1.02	[0.55; 1.91]	0.94

CI, confidence interval; D_mean, mean dose in the primary target volume; HR, hazard ratio; RT, radiation therapy.

Hypo + Ph/Lar + Lar is the group of patients with hypopharynx, pharyngeal-laryngeal and larynx tumours.

Variables in bold have p ≤ 0.05.