Table 7. Univariate analysis of potential prognostic factors.

Factors		OS	PFS	LPFS	RPFS	DMFS
Gender	male vs. female	0.668	0.117	0.330	0.211	0.433
Age	≤50 years vs. >50 years	0.463	0.536	0.352	0.670	0.665
Initial stage	I/II vs. III/IV	0.612	0.926	0.535	0.324	0.453
Time to recurrence after initial IMRT	≤2 years vs. >2 years	0.888	0.274	0.947	0.507	0.530
r-T classification	T0–2 vs.T3–4	0.004	0.057	0.305	0.106	0.059
r-N category	N0 vs. N1–2	0.913	0.295	0.224	0.784	0.318
Chemotherapy	Yes vs. No	0.698	0.739	0.439	0.886	0.191
GTV dose	≤66 Gy vs. >66 Gy or IMRT + Brachy	0.699	0.516	0.593	0.656	0.184
Response to re-IMRT	CR vs. PR + SD + PD	0.038	0.140	0.652	0.199	0.921
SAE (Mucosal necrosis, TLN, CNP)	Yes vs. No	0.034	0.000	0.579	0.895	0.405

SAE – severe adverse effects; TLN – temporal lobe necrosis; CNP – cranial nerve palsy.