Table 4.

Multivariate analysis of prognostic factors

Variate	OS		PFS		DMFS		LRRFS
	RR(95% CI)	P	RR(95% CI)	P	RR(95% CI)	P	RR(95% CI)	P
Group
RV-IMRT vs. CV-IMRT	0.580 (0.257–1.309)	0.19	0.826 (0.420–1.622)	0.578	1.285 (0.538–3.070)	0.573	0.553 (0.203–1.502)	0.245
Gender
Male vs. Female	0.970 (0.382–2.464)	0.95	1.918 (0.736–4.998)	0.183	2.979 (0.684–12.978)	0.146	1.563 (0.439–5.562)	0.49
Age
≥ 45 vs. < 45	2.408 (1.037–5.595)	0.041	1.451 (0.724–2.908)	0.294	1.053 (0.438–2.528)	0.909	1.607 (0.575–4.490)	0.365
T stage
T3–4 vs. T1–2	0.817 (0.340–1.964)	0.651	0.916 (0.415–2.021)	0.828	1.068 (0.396–2.885)	0.896	1.179 (0.368–3.776)	0.781
N stage
N2–3 vs. N0–1	2.455 (0.649–9.279)	0.186	2.192 (0.687–6.992)	0.185	2.715 (0.556–13.257)	0.217	1.490 (0.361–6.159)	0.581
Clinical stage
III-IV vs. I-II	3.280 (0.281–38.226)	0.343	0.926 (0.183–4.683)	0.926	0.730 (0.080–6.639)	0.78	1.165 (0.129–10.480)	0.892
Neoadjuvant/adjuvant chemotherapy
Yes vs. No	0.600 (0.085–4.238)	0.608	0.695 (0.108–4.464)	0.702	1.764 (0.084–36.960)	0.715	0.404 (0.047–3.457)	0.408
Concurrent chemotherapy
Yes vs. No	0.987 (0.041–23.701)	0.994	3.338 (0.237–46.915)	0.371	0.796 (0.030–20.935)	0.891	–	–

OS overall survival, PFS progression-free survival, DMFS distant metastasis-free survival, LRRFS locoregional recurrence-free survival, CV-IMRT conventional-volume intensity-modulated radiation therapy, RV-IMRT reduced-volume intensity-modulated radiation therapy