Table 1. Baseline Clinical Characteristics of Patients by Radiation Modality.
| Characteristic | Patients, No. (%) | P valuea | |
|---|---|---|---|
| IMPT (n = 28) | IMRT (n = 49) | ||
| Age at RT, median (IQR), y | 45.9 (42.0-59.6) | 49.5 (42.6-60.9) | .68 |
| Sex | |||
| Male | 19 (67.9) | 33 (67.3) | .96 |
| Female | 9 (32.1) | 16 (32.7) | |
| Smoking history | |||
| No | 21 (75.0) | 28 (57.1) | .12 |
| Yes | 7 (25.0) | 21 (42.9) | |
| KPS | |||
| 100 | 2 (7.1) | 6 (12.2) | .77 |
| 90 | 22 (78.6) | 38 (77.6) | |
| 80 | 4 (14.3) | 5 (10.2) | |
| T stage | |||
| Tx | 1 (3.6) | 0 | .09 |
| T1 | 7 (25.0) | 21 (42.9) | |
| T2 | 3 (10.7) | 8 (16.3) | |
| T3 | 9 (32.1) | 14 (28.6) | |
| T4 | 8 (28.6) | 6 (12.2) | |
| N stage | |||
| N0 | 7 (25.0) | 5 (10.2) | .33 |
| N1 | 10 (35.7) | 23 (46.9) | |
| N2 | 10 (35.7) | 18 (36.7) | |
| N3 | 1 (3.6) | 3 (6.1) | |
| AJCC eighth edition stage | |||
| I | 4 (14.3) | 3 (6.1) | .39 |
| II | 4 (14.3) | 13 (26.5) | |
| III | 11 (39.3) | 25 (51.0) | |
| IVA | 9 (32.1) | 8 (16.3) | |
| EBV status | |||
| Positive | 24 (85.7) | 45 (91.8) | .28 |
| Negative or unknown | 4 (14.3) | 4 (8.2) | |
| HPV status | |||
| Positive | 4 (14.3) | 1 (2.0) | .06 |
| Negative or unknown | 24 (85.7) | 48 (98.0) | |
| WHO Classification | |||
| Type 1, KSCC | 0 | 1 (2.0) | .45 |
| Type 2a, NKDC | 3 (10.7) | 3 (6.1) | |
| Type 2b, NKUC | 24 (85.7) | 45 (91.8) | |
| Basaloid | 1 (3.6) | 0 | |
| Treatment regimen | |||
| RT alone | 3 (10.7) | 3 (6.1) | .66 |
| Chemoradiotherapy | 25 (89.3) | 46 (93.9) | |
| Induction chemotherapy | 6 (21.4) | 3 (6.1) | .06 |
| Concurrent chemotherapy | 25 (89.3) | 46 (93.9) | .66 |
| Type of concurrent chemotherapy | |||
| High-dose cisplatin | 16 (57.1) | 12 (24.5) | .004 |
| Weekly cisplatin | 12 (42.9) | 37 (75.5) | |
| Adjuvant chemotherapy | 11 (39.3) | 26(53.1) | .34 |
| RT dose, median (IQR), GyE | 70.0 69.96-70.0) | 69.96 (69.96-69.96) | >.99 |
Abbreviations: AJCC, American Joint Committee on Cancer; EBV, Epstein-Barr virus; GyE, Gray equivalent; HPV, human papillomavirus; IMPT, intensity-modulated proton therapy; IMRT, intensity-modulated radiation therapy; IQR, interquartile range; KPS, Karnofsky Performance Score; KSCC, keratinizing squamous cell carcinoma; NKDC, nonkeratinizing differentiated carcinoma; NKUC, nonkeratinizing undifferentiated carcinoma; RT, radiotherapy; WHO, World Health Organization.
a
Categorical variables were assessed by χ2 test or Fisher exact test. Continuous variables were compared by Wilcoxon rank sum test.