Table 1.
Patient characteristics of the study population in the primary analysis
| Unmatched population | Matched study population | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| IGRT (n = 297) | non‐IGRT (n = 758) | IGRT (n = 295) | non‐IGRT (n = 295) | ||||||||
| Number or mean (sd)† | (%)† | Number or mean (sd)† | (%)† | SDif† | Number or mean (sd)† | (%)† | Number or mean (sd)† | (%)† | SDif† | ||
| Age | < 65 | 219 | (74) | 590 | (78) | 0.096 | 219 | (74) | 222 | (75) | 0.023 |
| ≥ 65 | 78 | (26) | 168 | (22) | 76 | (26) | 73 | (25) | |||
| Gender | Female | 13 | (4) | 45 | (6) | 0.071 | 13 | (4) | 12 | (4) | 0.017 |
| Male | 284 | (96) | 713 | (94) | 282 | (96) | 283 | (96) | |||
| Residency | Non‐north | 214 | (72) | 518 | (68) | 0.081 | 212 | (72) | 217 | (74) | 0.038 |
| North | 83 | (28) | 240 | (32) | 83 | (28) | 78 | (26) | |||
| Comorbidity | Without | 179 | (60) | 466 | (61) | 0.025 | 178 | (60) | 178 | (60) | 0 |
| With‡ | 118 | (40) | 292 | (39) | 117 | (40) | 117 | (40) | |||
| T‐stage | T1‐T2 | 51 | (17) | 83 | (11) | 0.180 | 49 | (17) | 45 | (15) | 0.037 |
| T3‐T4 | 246 | (83) | 675 | (89) | 246 | (83) | 250 | (85) | |||
| N‐stage | Negative | 19 | (6) | 82 | (11) | 0.158 | 19 | (6) | 18 | (6) | 0.014 |
| Positive | 278 | (94) | 676 | (89) | 276 | (94) | 277 | (94) | |||
| RT delivery | 3DCRT | § | § | § | § | 0.241 | § | § | § | § | 0 |
| IMRT | § | § | § | § | § | § | § | § | |||
| Use of PET | No | 69 | (23) | 198 | (26) | 0.067 | 69 | (23) | 67 | (23) | 0.016 |
| Yes | 228 | (77) | 560 | (74) | 226 | (77) | 228 | (77) | |||
| Drinking | No | 42 | (14) | 112 | (15) | 0.018 | 41 | (14) | 40 | (14) | 0.010 |
| Yes | 255 | (86) | 646 | (85) | 254 | (86) | 255 | (86) | |||
| Betel nut chewing | No | 151 | (51) | 335 | (44) | 0.133 | 149 | (51) | 148 | (50) | 0.007 |
| Yes | 146 | (49) | 423 | (56) | 146 | (49) | 147 | (50) | |||
| Smoking | No | 44 | (15) | 99 | (13) | 0.051 | 43 | (15) | 42 | (14) | 0.010 |
| Yes | 253 | (85) | 659 | (87) | 252 | (85) | 253 | (86) | |||
| BMI | 22.01 (3.36) | 21.47 (3.61) | 0.154 | 22.00 (3.37) | 22.06 (3.82) | 0.016 | |||||
†
Rounded.
‡
Carlson comorbidity score ≥ 1.
§
The exact numbers were not reported because of a Health and Welfare Data Science Center (HWDC) database center policy to avoid numbers in single cells (≤2).
3DCRT, 3D conformal radiotherapy; BMI, body mass index; IGRT, image‐guided radiotherapy; IMRT, intensity‐modulated radiotherapy; PET, positron emission tomography; RT, radiotherapy; sd, standard deviation; SDif, standardized difference.