Table 5.
Multivariable analysis of prognostic factors of the 3,808 patients with stage II NPC
| HR (95% CI) | p-value | |
|---|---|---|
| Overall survival | ||
| Age (yr) | 1.344 (1.287-1.403) | < 0.001 |
| Sex | 1.209 (1.032-1.417) | 0.019 |
| T category | 1.237 (1.054-1.453) | 0.009 |
| N category | 1.723 (1.511-1.964) | < 0.001 |
| Smoking | 1.189 (1.039-1.360) | 0.012 |
| Diabetes mellitus | 0.922 (0.561-1.514) | 0.748 |
| Family history of NPC | 0.793 (0.646-0.974) | 0.027 |
| Type of treatment | 0.762 (0.637-0.911) | 0.003 |
| Radiotherapy technique | 0.634 (0.542-0.742) | < 0.001 |
| Progression-free survival | ||
| Age (yr) | 1.262 (1.212-1.315) | < 0.001 |
| Sex | 1.214 (1.051-1.403) | 0.009 |
| T category | 1.235 (1.063-1.434) | 0.006 |
| N category | 1.599 (1.417-1.805) | < 0.001 |
| Smoking | 1.108 (0.979-1.255) | 0.104 |
| Diabetes mellitus | 0.929 (0.602-1.435) | 0.741 |
| Family history of NPC | 0.821 (0.681-0.990) | 0.039 |
| Type of treatment | 0.800 (0.683-0.937) | 0.006 |
| Radiotherapy technique | 0.758 (0.688-0.837) | < 0.001 |
| Locoregional relapse-free survival | ||
| Age (yr) | 1.154 (1.093-1.218) | < 0.001 |
| Sex | 1.150 (0.956-1.384) | 0.138 |
| T category | 1.482 (1.202-1.828) | < 0.001 |
| N category | 1.514 (1.294-1.770) | < 0.001 |
| Smoking | 1.043 (0.886-1.227) | 0.616 |
| Diabetes mellitus | 0.605 (0.300-1.218) | 0.159 |
| Family history of NPC | 0.837 (0.657-1.067) | 0.152 |
| Type of treatment | 0.699 (0.565-0.865) | 0.001 |
| Radiotherapy technique | 0.696 (0.607-0.799) | < 0.001 |
| Distant metastasis-free survival | ||
| Age (yr) | 1.119 (1.023-1.224) | 0.014 |
| Sex | 1.495 (1.095-2.041) | 0.011 |
| T category | 1.230 (0.900-1.681) | 0.194 |
| N category | 1.732 (1.327-2.261) | < 0.001 |
| Smoking | 1.000 (0.773-1.294) | 0.998 |
| Diabetes mellitus | 1.448 (0.710-2.953) | 0.308 |
| Family history of NPC | 0.949 (0.654-1.377) | 0.783 |
| Type of treatment | 0.994 (0.739-1.337) | 0.969 |
| Radiotherapy technique | 0.891 (0.768-1.034) | 0.130 |
A Cox proportional hazards regression model was used to detect variables. All variables were transformed into categorical variables. HRs were calculated for age (yr) (≥ 60 vs. 50-59 vs. 40-49 vs. ≤ 39); sex (male vs. female); T category (II vs. I); N category (I vs. 0); smoking (yes vs. no); diabetes mellitus (yes vs. no); family history of NPC (yes vs. no); type of treatment (CRT vs. RT); and radiotherapy technique (IMRT vs. 3DRT vs. CT-SIM vs. 2DCRT). NPC, nasopharyngeal carcinoma; HR, hazard ratio; CI, confidence interval; CRT, chemoradiotherapy; RT, radiotherapy; IMRT, intensity-modulated radiotherapy; 3DRT, three-dimensional conformal radiotherapy; CT-SIM, computed tomography simulator; 2DCRT, two-dimensional conventional radiotherapy.