Table 2.
Factors associated with ctDNA detection.
| ctDNA in pretreatment plasma | p value* | ctDNA in follow-up plasma | p value* | |
|---|---|---|---|---|
| Gender (male vs. female) | 3/4 vs. 7/16 | 0.582 | 2/4 vs. 3/16 | 0.248 |
| Stage group (I, II vs. III, IV) | 3/9 vs. 7/11 | 0.369 | 0/9 vs. 05/11 | 0.0378 |
| T stage (1, 2 vs. 3, 4) | 5/11 vs. 5/9 | 1.0 | 1/11 vs. 4/9 | 0.127 |
| N stage (positive vs. negative) | 8/15 vs. 2/5 | 1.0 | 4/15 vs. 1/5 | 1.0 |
| Local recurrence (positive vs. negative) | 2/6 vs. 8/14 | 0.628 | 4/6 vs. 1/14 | 0.0139 |
| Distant metastasis (positive vs. negative) | 3/4 vs. 7/16 | 0.580 | 4/4 vs. 1/16 | 0.001 |
| HPV status (positive vs. negative or unknown) | 5/11 vs. 6/9 | 0.406 | 0/11 vs. 5/9 | 0.008 |
| Age (< 65 vs. 65 ≦) | 8/12 vs. 3/8 | 0.361 | 3/12 vs. 2/8 | 1.0 |
*Fisher’s test.
Post-treatment detection of ctDNA in plasma and Fisher test were performed for each item. Post-treatment detection was associated with stage, local recurrence, and distant metastasis.