Table 1.
Univariable analyses of factors related to level IB LNs metastases at diagnosis in 1438 patients
| Variable | Metastasis to level Ib LNs at diagnosis, N (%) | *P | |
|---|---|---|---|
| (−), n = 1398 | (+), n = 40 | ||
| Sex | |||
| Male | 1052 (75.3) | 33 (82.5) | .294 |
| Female | 346 (24.7) | 7 (17.5) | |
| Age | |||
| <50 years | 950 (68.0) | 23 (57.5) | .163 |
| ≥50 years | 448 (32.0) | 17 (42.5) | |
| Histologic type | |||
| Keratinizing squamous cell carcinoma | 5 (0.4) | 0 | 1.000 |
| Nonkeratinizing carcinoma | 1393 (99.6) | 40 (100.0) | |
| T stage | ’ | ||
| T1 | 247 (17.7) | 5 (12.5) | .537 |
| T2 | 207 (14.8) | 6 (15.0) | |
| T3 | 679 (48.6) | 18 (45.0) | |
| T4 | 265 (19.0) | 11 (27.5) | |
| T classification | |||
| T1-3 | 1133 (81.0) | 29 (72.5) | .176 |
| T4 | 265 (19.0) | 11 (27.5) | |
| Oropharynx involvement | |||
| (−) | 1291 (92.3) | 31 (77.5) | .001 |
| (+) | 107 (7.7) | 9 (22.5) | |
| Nasal cavity involvement | |||
| (−) | 918 (65.7) | 22 (55.0) | .162 |
| (+) | 480 (34.3) | 18 (45.0) | |
| N classification | |||
| N0 | 235 (16.8) | 0 | <.001 |
| N1 | 823 (58.9) | 19 (47.5) | |
| N2 | 216 (15.5) | 13 (32.5) | |
| N3 | 124 (8.9) | 8 (20.1) | |
| Positive RLNs | |||
| (−) | 387 (27.7) | 3 (7.5) | .005 |
| (+) | 1011 (72.3) | 37 (92.5) | |
| Positive CLNs | |||
| (−) | 570 (40.8) | 4 (10.0) | <.001 |
| (+) | 828 (59.2) | 36 (90.0) | |
| LN necrosis | |||
| (−) | 1054 (75.4) | 22 (55.0) | <.001 |
| (+) | 344 (24.6) | 18 (45.0) | |
| LNs with ES | |||
| (−) | 1051 (75.2) | 26 (65.0) | .143 |
| (+) | 347 (24.8) | 14 (35.0) | |
| DLN-IIa ≥30 mm or level IIa LNs with ES | |||
| (−) | 1247 (89.2) | 34 (85.0) | .435 |
| (+) | 151 (10.8) | 6 (15.0) | |
| DLN-IIa ≥20 mm or level IIa LNs with ES | |||
| (−) | 1113 (79.6) | 19 (47.5) | <.001 |
| (+) | 285 (20.4) | 21 (52.5) | |
| MAD of LNs ≥30 mm | |||
| (−) | 1196 (85.6) | 26 (65.0) | <.001 |
| (+) | 202 (14.4) | 14 (35.0) | |
| Positive bilateral CLNs | |||
| (−) | 1121 (80.2) | 20 (50.0) | <.001 |
| (+) | 277 (19.8) | 20 (50.0) | |
| Positive CLNs at supraclavicular fossa | |||
| (−) | 1318 (94.3) | 21 (80.0) | <.001 |
| (+) | 80 (5.7) | 8 (20.0) | |
Abbreviations: LNs, lymph nodes; WHO, World Health Organization; RLNs, retropharyngeal lymph nodes; CLNs, cervical lymph nodes; LNs, lymph nodes; DLN-IIa, greatest dimension of level IIa lymph nodes; MAD, maximal axial diameter; ES, extra-capsular spread
*P-values were calculated using an unadjusted chi-square test (or Fisher’s exact test, if indicated)