Table 3.
Metastatic rates of small cervical lymph nodes based on MRI and PET/CT findings stratified by N category
| MRI-based N category | Group A | Group B | Group C | Group D | Group E | P c | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Totala | Metastatic lymph nodes (%)b | Totala | Metastatic lymph nodes (%)b | Totala | Metastatic lymph nodes (%)b | Totala | Metastatic lymph nodes (%)b | Totala | Metastatic lymph nodes (%)b | ||
| N0 category | |||||||||||
| Level I | 37 | 0 (0) | 9 | 0 (0) | 4 | 0 (0) | 1 | 0 (0) | 0 | 0 (0) | 1.000 |
| Level II | 75 | 0 (0) | 47 | 0 (0) | 37 | 4 (10.8) | 17 | 7 (41.2) | 7 | 6 (85.7) | < 0.001 |
| Level III/Va | 16 | 0 (0) | 8 | 1 (12.5) | 1 | 0 (0) | 2 | 1 (50.0) | 1 | 1 (100.0) | 0.036 |
| Level IV/Vb | 6 | 0 (0) | 3 | 0 (0) | 1 | 0 (0) | 0 | 0 (0) | 0 | 0 (0) | 1.000 |
| P c1 | 1.000 | 0.164 | 1.000 | 1.000 | 1.000 | ||||||
| P c2 | 1.000 | 0.190 | 1.000 | 0.812 | 1.000 | ||||||
| N1 category | |||||||||||
| Level I | 115 | 0 (0) | 41 | 0 (0) | 21 | 0 (0) | 7 | 1 (14.3) | 2 | 2 (100.0) | < 0.001 |
| Level II | 239 | 8 (3.3) | 189 | 34 (18.0) | 168 | 54 (32.1) | 95 | 54 (56.8) | 68 | 56 (82.4) | < 0.001 |
| Level III/Va | 85 | 7 (8.2) | 52 | 3 (5.8) | 25 | 8 (32.0) | 13 | 9 (69.2) | 5 | 5 (100.0) | < 0.001 |
| Level IV/Vb | 19 | 1 (5.3) | 17 | 2 (11.8) | 8 | 4 (50.0) | 9 | 7 (77.8) | 4 | 4 (100.0) | < 0.001 |
| P c1 | 0.008 | < 0.001 | 0.001 | 0.045 | 0.746 | ||||||
| P c2 | 0.147 | 0.056 | 0.592 | 0.341 | 0.647 | ||||||
| N2 category | |||||||||||
| Level I | 22 | 0 (0) | 16 | 0 (0) | 6 | 1 (16.7) | 1 | 0 (0) | 1 | 1 (100.0) | 0.013 |
| Level II | 66 | 6 (9.1) | 67 | 8 (11.9) | 44 | 17 (38.6) | 35 | 21 (60.0) | 27 | 21 (77.8) | < 0.001 |
| Level III/Va | 54 | 1 (1.9) | 20 | 4 (20.0) | 18 | 8 (44.4) | 10 | 7 (70.0) | 2 | 2 (100.0) | < 0.001 |
| Level IV/Vb | 8 | 1 (12.5) | 4 | 0 (0) | 2 | 0 (0) | 3 | 3 (100.0) | 1 | 1 (100.0) | 0.007 |
| P c1 | 0.151 | 0.305 | 0.441 | 0.130 | 1.000 | ||||||
| P c2 | 0.135 | 0.593 | 0.623 | 0.074 | 1.000 | ||||||
| N3 category | |||||||||||
| Level I | 23 | 0 (0) | 4 | 0 (0) | 3 | 1 (33.3) | 1 | 1 (100.0) | 0 | 0 (0) | 0.013 |
| Level II | 16 | 3 (18.8) | 26 | 7 (26.9) | 14 | 5 (35.7) | 20 | 12 (60.0) | 9 | 8 (88.9) | < 0.001 |
| Level III/Va | 15 | 0 (0) | 11 | 0 (0) | 14 | 7 (50.0) | 9 | 7 (77.8) | 4 | 3 (75.0) | < 0.001 |
| Level IV/Vb | 12 | 1 (8.3) | 12 | 2 (16.7) | 8 | 8 (100.0) | 14 | 12 (85.7) | 6 | 5 (83.3) | < 0.001 |
| P c1 | 0.038 | 0.232 | 0.006 | 0.380 | 1.000 | ||||||
| P c2 | 0.117 | 0.06 | 0.003 | 0.225 | 1.000 | ||||||
MRI magnetic resonance imaging, PET/CT positron emission tomography/computed tomography
aTotal number of small cervical lymph nodes based on MRI findings
bMetastatic number of small cervical lymph nodes based on PET/CT findings
c P values were calculated using the Chi square test or Fisher’s exact test if indicated; P c1: Comparison between levels I, II, III/Va and IV/Vb; P c2: Comparison between levels II, III/Va and IV/Vb