Table 4. IMRT versus 2DCRT in subgroup analysis by tumor stage in multivariate analysis in the propensity-matched cohort*.
| Subgroup | Overall survival | Locoregional relapse-free survival | Distant metastasis-free survival | |||
|---|---|---|---|---|---|---|
| Hazard ratio (95% CI) | P | Hazard ratio (95% CI) | P | Hazard ratio (95% CI) | P | |
| T-stage | ||||||
| T1-2 | 1.27 (0.51-3.17) | 0.608 | 1.12 (0.51-2.44) | 0.780 | 2.51 (0.79-7.93) | 0.118 |
| T3-4 | 1.27 (0.65-2.50) | 0.481 | 1.49 (0.49-4.57) | 0.486 | 0.62 (0.28-1.38) | 0.243 |
| N-stage | ||||||
| N0-1 | 1.59 (0.89-2.87) | 0.119 | 1.28 (0.64-2.56) | 0.481 | 1.21 (0.63-2.32) | 0.572 |
| N2-3 | 0.43 (0.16-1.18) | 0.102 | 0.90 (0.23-3.55) | 0.878 | 0.36 (0.06-2.37) | 0.290 |
| Clinical stage | ||||||
| I+II | 1.65 (0.61-4.47) | 0.325 | 1.44 (0.60-3.46) | 0.411 | 2.34 (0.71-7.69) | 0.161 |
| III+IV | 1.17 (0.62-2.21) | 0.633 | 1.07 (0.42-2.72) | 0.890 | 0.63 (0.28-1.38) | 0.245 |
Abbreviations: IMRT = intensity-modulated radiotherapy, 2DCRT = two-dimensional conventional radiotherapy, CI = confidence interval
*
Adjusted for age (continuous), sex, histology, immunoglobulin A against viral capsid antigen (<80/80-320/≥320), immunoglobulin A against early antigen (<10/10-40/≥40), T-stage and N-stage by forward selection with a robust variance estimator to account for the clustering within matched pair.