Table 2.
Stepwise Univariate and Multivariate Cox Regression Analyses to Identify Predictors of Grade ≥ 2 RP
| Characteristics | Univariate Analysis (RP ≥ grade 2) |
Multivariate Analysis (RP ≥ grade 2)⁎ |
||||
|---|---|---|---|---|---|---|
| HR | 95% CI | P | HR | 95% CI | P | |
| Age (≥66 vs <66) | 1.236 | 0.964-1.585 | .095 | 1.361 | 1.038-1.784 | .026 |
| Gender (male vs female) | 1.005 | 0.784-1.290 | .966 | 0.882 | 0.673-1.155 | .361 |
| Race (black and other vs white) | 1.053 | 0.742-1.493 | .773 | 0.876 | 0.605-1.267 | .481 |
| Disease stage (IIIB, IV, recurrence vs I-IIIA) | 1.010 | 0.782-1.303 | .941 | 0.857 | 0.653-1.126 | .269 |
| Histology (SCC & other vs Adn) | 0.954 | 0.743-1.224 | .711 | 0.982 | 0.749-1.287 | .894 |
| KPS (≥80 vs <80) | 0.771 | 0.554-1.075 | .125 | 0.687 | 0.481-0.98 | .038 |
| Concurrent chemotherapy (yes vs no) | 1.102 | 0.739-1.644 | .633 | 0.966 | 0.609-1.532 | .966 |
| Smoking status (current/former vs never) | 0.825 | 0.532-1.279 | .39 | 0.769 | 0.474-1.248 | .288 |
| Total dose (≥69.03 vs <69.03 Gy) | 0.799 | 0.622-1.026 | .079 | 0.83 | 0.63-1.093 | .184 |
| GTV (≥95.19 vs <95.19 cm3) | 1.539 | 1.186-1.999 | .001 | 1.299 | 0.977-1.726 | .072 |
| MLD (≥17.93 vs <17.93 Gy) | 2.08 | 1.601-2.703 | .001 | 1.883 | 1.402-2.528 | <.001 |
| Technique (proton vs 3D-CRT + IMRT) | 0.932 | 0.688-1.263 | .65 | 1.105 | 0.794-1.537 | .555 |
| Muc5b rs35705950 (TT/GT vs GG) | 1.009 | 0.728-1.399 | .958 | 0.921 | 0.645-1.315 | .65 |
Abbreviations: NI, not included; KPS, Karnofsky Performance Status score; SCC, squamous cell carcinoma; 3D-CRT, 3-dimensional conformal (photon) radiation therapy; IMRT, intensity-modulated (photon) radiation therapy.
⁎
The propensity score was used for adjustments of confounders in the multivariate analysis.