Table 1.
Patient clinicopathological characteristics
| Variable | No. | % |
|---|---|---|
| Age, years | ||
| ≤70 | 173 | 50.1 |
| >70 | 172 | 49.9 |
| Sex | ||
| Male | 186 | 53.9 |
| Female | 159 | 46.1 |
| ECOG performance status (PS) | ||
| PS0–1 | 260 | 75.4 |
| PS≥2 | 22 | 6.4 |
| Unknown | 63 | 18.3 |
| T classification (UICC/AJCC) | ||
| T1 | 42 | 12.1 |
| T2 | 88 | 25.5 |
| T3 | 14 | 4.1 |
| T4a | 171 | 49.6 |
| T4b | 30 | 8.7 |
| N classification | ||
| N0 | 213 | 61.7 |
| N1 | 62 | 18.0 |
| N2 | 69 | 20.0 |
| N3 | 1 | 0.3 |
| Bone invasion | ||
| No bone invasion | 144 | 41.7 |
| Medullary | 107 | 31.0 |
| MC | 94 | 27.2 |
| Tumor differentiation | ||
| Well‐moderately | 315 | 91.3 |
| Poorly | 16 | 4.6 |
| Unknown | 14 | 4.1 |
| Treatment | ||
| Surgery | 334 | 96.8 |
| CCRT | 11 | 3.2 |
| Excision margin | ||
| Clear | 184 | 53.3 |
| Close‐involved | 29 | 8.4 |
| ND | 132 | 38.3 |
| Number of positive nodes (PLN) | ||
| PLN0 | 232 | 67.2 |
| PLN1‐2 | 62 | 18.0 |
| PN≥3 | 51 | 14.8 |
| Extracapsular nodal spread | ||
| Absent | 316 | 91.6 |
| Present | 29 | 8.4 |
| Adjuvant radiotherapy | ||
| Yes | 295 | 85.5 |
| No | 50 | 14.5 |
ECOG, Eastern cooperative oncology group; MC, mandibular canal; ND, not determined; CCRT, Concurrent chemotherapy and radiotherapy