Table 2.
Summary of multivariate analyses of prognostic factors in 333 nasopharyngeal carcinoma patients
| Endpoint | Variable | Estimate | HR† | 95% CI* | P value‡ |
|---|---|---|---|---|---|
| OS |
Age |
-0.403 |
0.668 |
0.450-0.993 |
0.046 |
| |
N stage |
0.312 |
1.366 |
1.037-1.799 |
0.027 |
| |
MPTD |
0.720 |
2.054 |
1.509-2.794 |
< 0.001 |
| FFS |
N stage |
0.527 |
1.694 |
1.218-2.357 |
0.002 |
| |
MPTD |
0.713 |
2.040 |
1.426-2.919 |
< 0.001 |
| DMFS |
N stage |
0.628 |
1.873 |
1.269-2.766 |
0.002 |
| |
MPTD |
0.563 |
1.757 |
1.155-2.671 |
0.008 |
| LRFS | MPTD | 0.955 | 2.598 | 1.342-5.033 | 0.005 |
†HR: Hazard ratio from Cox proportional hazards model; *CI, confidence interval; ‡P values were calculated using an adjusted Cox proportional-hazards model. OS, overall survival; FFS, failure-free survival; DMFS, distant metastasis-free survival; LRFS, local relapse-free survival; MPTD, maximum primary tumor diameter. The following parameters were included in the model as the covariates for each analysis: age (≤ 45 vs. > 45 years), sex, chemotherapy (yes vs. no) and radiation technique (2-DRT vs. 3-DCRT). For analysis of OS, FFS and DMFS, the following additional covariates were introduced into the model: T stage (T1 vs. T2 vs. T3 vs. T4), N stage (N0 vs. N1 vs. N2 vs. N3), and MPTD (≤ 30 mm vs. > 30–50 mm vs. > 50 mm). For analysis of LRFS, the following additional covariates were taken into account: intracranial extension, skull base erosion, nasal extension, oropharyngeal extension, paranasopharyngeal extension and MPTD. We have only presented the results for MPTD and other statistically significant variables.