TABLE 2.
Factors associated with baseline CTCs
| 0 CTCs (%) (n = 26) | ≥ 1 CTCs (%) (n = 10) | P value | |
|---|---|---|---|
| Primary tumor location | |||
| Oropharynx | 19 (73.1%) | 4 (40.0%) | .119 |
| Other | 7 (26.9%) | 6 (60.0%) | |
| T staging a | |||
| T1 | 5 (20.8%) | 2 (25.0%) | .449 |
| T2 | 6 (25.0%) | 4 (50.0%) | |
| T3 | 9 (37.5%) | 1 (12.5%) | |
| T4 | 4 (16.7%) | 1 (12.5%) | |
| N staging b | |||
| <N2b | 7 (26.9%) | 1 (14.3%) | .652 |
| ≥N2b | 19 (73.1%) | 6 (85.7%) | |
| Disease burden at time of draw | |||
| LAD | 19 (73.1%) | 6 (60.0%) | .454 |
| Metastatic disease | 7 (26.9%) | 4 (40.0%) | |
| HPV status c | |||
| Positive | 18 (85.7%) | 5 (83.3%) | 1 |
| Negative | 3 (14.3%) | 1 (16.7%) | |
| Smoking history | |||
| <10 pack‐years | 18 (69.2%) | 1 (10.0%) | .002 |
| ≥10 pack‐years | 8 (30.8%) | 9 (90.0%) | |
| Alcohol history d | |||
| <5 drinks/wk | 15 (62.5%) | 4 (40.0%) | .276 |
| ≥5 drinks/wk | 9 (37.5%) | 6 (60.0%) | |
| Median OS e (range), mo | 32.10 (3‐72) | 30.30 (1‐70) | .337 |
| Median PFS f (range), mo | 28.00 (1‐71) | 28.00 (1‐70) | .614 |
Abbreviations: CTC, circulating tumor cells, HPV, human papillomavirus; LAD, locally advanced disease; OS, overall survival, PFS, progression‐free survival.
a
Two patients in the “0 CTCs” group and two patients in the “CTCs observed” group had unknown T‐staging.
b
Three patients in the “≥1 CTCs group” had unknown N staging.
c
Five patients in the “0 CTCs” group and four patients in the “CTCs observed” group had unknown HPV status.
d
Two patients in the “0 CTCs” group had unknown alcohol history.
e
PFS is until disease progression or last available follow‐up.
f
OS is until death or last available follow‐up.