**4. Discussion**

128 Carcinogenesis, Diagnosis, and Molecular Targeted Treatment for Nasopharyngeal Carcinoma

respectively), but no significant differences were observed between Groups 2 and 3 (*P* = 0.322 and *P* = 0.809, respectively). No significant differences were observed in the LRFS rates between Groups 1 and 2 (*P* = 0.750), and no significant difference was observed

Multivariate analysis was performed to adjust for various prognostic factors in T3 and T4 disease. Parameters were included in the Cox proportional hazards model by backward elimination of insignificant explanatory variables: age (50<=years vs >50 years), sex, skull base extension, paranasal sinus extension, intracranial extension, infratemporal extension, orbital extension hypopharynx extension, MRI-detected CN involvement, CN palsy, N classification, radiotherapy technique, and chemotherapy. Both clinical CN palsy and MRIdetected CN involvement were significant predictive factors for the DMFS and OS rates in

Endpoint Variable B Exp(B) 95% CI for

OS, overall survival; LRFS, local relapse-free survival; DMFS, metastasis-free survival. Table 2. Summary of Multivariate Analyses of Prognostic Factors in T3-4 Disease.

**3.4 Difference in the prognostic implications between clinical CN palsy and** 

In 336 patients with clinical and/or MRI-detected CN involvement, no significant difference was observed in the 3-year DMFS (74.6% vs 84.6%, *P* = 0.094) or LRFS (86.7% vs 87.9%, *P* = 0.899) rates between patients with and without clinically detected CN palsies. A marginally significant difference was observed in the 3-year OS (74.2% vs 80.1%, *P* = 0.067) rate; however, after adjusting for N classification, there was no significant difference (*P* = 0.102).

**3.5 Prognosis of lesion localization in patients with MRI-detected CN involvement** 

Of the 333 patients with MRI-detected CN involvement, no significant differences were observed with regard to the 3-year OS (78.3% vs 72.9%, *P* = 0.120), LRFS (89.7% vs 84.1%, *P* = 0.154) or DMFS (79.6% vs 74.8%, *P* = 0.466) rates between patients with and without

age -0.287 0.750 0.550-1.024 0.070 MRI-detected CN involvement 0.866 2.377 1.620-3.489 0.000 CN palsy -0.662 0.516 0.300-0.886 0.016 intracranial extension 0.511 1.667 1.104-2.516 0.015 N classification 0.487 1.627 1.396-1.898 0.000

MRI-detected CN involvement 0.627 1.871 1.268-2.762 0.002 CN palsy -0.506 0.603 0.330-1.102 0.100 paranasal sinuses extension 0.509 1.665 1.087-2.547 0.019 N classification 0.576 1.778 1.510-2.094 0.000

age -0.379 0.685 0.457-1.026 0.066 gender -0.855 0.425 0.232-0.779 0.006 intracranial extension 0.787 2.197 1.424-3.389 0.000

Exp(B) *<sup>P</sup>*

between Groups 2 and 3 (*P* = 0.079).

local advanced disease (Table 2).

**MRI-detected CN involvement** 

intracranial or orbital MRI-detected CN involvement.

OS

DMFS

LRFS
