Table 1 Patient characteristics of the study population in the primary analysis
Unmatched population | Matched study population | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
Short interval (n = 169) | Long interval (n = 87) | Short interval (n = 80) | Long interval (n = 80) | ||||||||
Number or mean (sd)† | (%)† | Number or mean (sd)† | (%)† | SDif† | Number or mean (sd)† | (%)† | Number or mean (sd)† | (%)† | SDif† | ||
Age | 54.71 (8.53) | 53.21 (8.30) | 0.179 | 53.48 (8.62) | 52.94 (8.31) | 0.063 | |||||
Gender | Female | 13 | (8) | 5 | (6) | 0.078 | 5 | (6) | 5 | (6) | 0 |
Male | 156 | (92) | 82 | (94) | 75 | (94) | 75 | (94) | |||
Residency | Non-north | 110 | (65) | 46 | (53) | 0.250 | 46 | (57) | 45 | (56) | 0.025 |
North | 59 | (35) | 41 | (47) | 34 | (43) | 35 | (44) | |||
Tumor size | ≤ 5 cm | 61 | (36) | 43 | (49) | 0.272 | 35 | (44) | 37 | (46) | 0.050 |
> 5 cm | 108 | (64) | 44 | (51) | 45 | (56) | 43 | (54) | |||
Tumor differentiation | Poorly/undifferentiated | 66 | (39) | 15 | (17) | 0.500 | 15 | (19) | 15 | (19) | 0 |
Well/moderately | 103 | (61) | 72 | (83) | 65 | (81) | 65 | (81) | |||
RT delivery | Non-IGRT | 145 | (86) | 62 | (71) | 0.360 | 62 | (77) | 60 | (75) | 0.059 |
IGRT | 24 | (14) | 25 | (29) | 18 | (23) | 20 | (25) | |||
Use of PET | No | 14 | (8) | 7 | (8) | 0.009 | 5 | (6) | 7 | (9) | 0.095 |
Yes | 155 | (92) | 80 | (92) | 75 | (94) | 73 | (91) | |||
Tumor location | Cervical | ‡ | ‡ | ‡ | ‡ | 0.220 | ‡ | ‡ | ‡ | ‡ | 0 |
Non-cervical | ‡ | ‡ | ‡ | ‡ | ‡ | ‡ | ‡ | ‡ | |||
T-stage | T1–T2 | 21 | (12) | 10 | (11) | 0.029 | 10 | (13) | 10 | (13) | 0 |
T3–T4 | 148 | (88) | 77 | (89) | 70 | (87) | 70 | (87) | |||
N-stage | Negative | 20 | (12) | 8 | (9) | 0.086 | 14 | (18) | 8 | (10) | 0.219 |
Positive | 149 | (88) | 79 | (91) | 66 | (82) | 72 | (90) | |||
Drinking | No | 23 | (14) | 7 | (8) | 0.180 | 8 | (10) | 7 | (9) | 0.043 |
Yes | 146 | (86) | 80 | (92) | 72 | (90) | 73 | (91) | |||
Betel nut chewing | No | 75 | (44) | 30 | (34) | 0.204 | 29 | (36) | 28 | (35) | 0.026 |
Yes | 94 | (56) | 57 | (66) | 51 | (64) | 52 | (65) | |||
Smoking | No | 24 | (14) | 10 | (11) | 0.081 | 10 | (13) | 10 | (13) | 0 |
Yes | 145 | (86) | 77 | (89) | 70 | (87) | 70 | (87) | |||
BMI | 22.08 (3.34) | 22.69 (4.62) | 0.152 | 21.91 (3.35) | 22.39 (3.32) | 0.146 | |||||
Number of lymph nodes | < 15 | 33 | (20) | 17 | (20) | 0 | 20 | (25) | 16 | (20) | 0.120 |
≥ 15 | 136 | (80) | 70 | (80) | 60 | (75) | 64 | (80) | |||
RT dose (Gy) | 48.30 (3.30) | 46.80 (4.06) | 0.405 | 47.51 (3.59) | 47.16 (3.92) | 0.094 | |||||