Table 3.
Conditional probability and risk difference of CAT metastasis according to cervical lymph node involvement and tumor location.
| Tumor location | P(CAT+) (%) | Region | P(CAT+ | region+) (%) | P(CAT+ | region-) (%) | Delta Risk (%) |
|---|---|---|---|---|---|
| Overall | 42.4 | VI | 44.8 (150/335) | 32.0 (24/75) | 12.8 |
| II | 53.1 (77/145) | 36.6 (97/265) | 16.5 | ||
| III | 47.3 (116/245) | 35.2 (58/165) | 12.1 | ||
| IV+V | 43.8 (133/303) | 38.3 (41/107) | 5.5 | ||
| Upper pole | 55.1 | VI | 59.5 (69/116) | 42.1 (16/38) | 17.4 |
| II | 66.2 (45/68) | 46.5 (40/86) | 19.7 | ||
| III | 58.4 (59/101) | 49.1 (26/53) | 9.3 | ||
| IV+V | 61.1 (66/108) | 41.3 (19/46) | 19.8 | ||
| Middle pole | 42.1 | VI | 44.8 (69/154) | 25.0 (6/24) | 19.8 |
| II | 50.9 (29/57) | 38.0 (46/121) | 12.9 | ||
| III | 46.7 (50/107) | 35.2 (25/71) | 11.5 | ||
| IV+V | 41.3 (55/133) | 44.4 (20/45) | -3.1 | ||
| Lower pole | 17.9 | VI | 18.5 (12/65) | 15.4 (2/13) | 3.1 |
| II | 15.0 (3/20) | 19.0 (11/58) | -4.0 | ||
| III | 18.9 (7/37) | 17.1 (7/41) | 1.8 | ||
| IV+V | 19.3 (12/62) | 12.5 (2/16) | 6.8 |
CAT, carotid triangle. P(CAT+) indicates the overall probability of CAT LN metastasis. P(CAT+ | region+) indicates the probability of CAT LN metastasis when metastasis is present in the specified region. P(CAT+ | region-) indicates the probability when metastasis is absent in that region. Delta Risk = P(CAT+ | region+) - P(CAT+ | region-).