TABLE 2.
Concordance of common genes between ctDNA and tissue‐DNA among patients with biliary tract cancers whose ctDNA and tissue‐DNA were both analyzed (n = 40)
| Patients who had both ctDNA and tissue‐DNA sequencing (n = 40) | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Tissue‐DNA (+) | Tissue‐DNA (−) | Overall concordance | Kappa a (SE) | ||||||||
| TP53 | ctDNA (+) | 7 | 6 | 67.5% | 0.27 (0.16) | ||||||
| ctDNA (−) | 7 | 20 | |||||||||
| KRAS | ctDNA (+) | 8 | 3 | 80.0% | 0.53 (0.15) | ||||||
| ctDNA (−) | 5 | 24 | |||||||||
| PIK3CA | ctDNA (+) | 3 | 4 | 90.0% | 0.55 (0.19) | ||||||
| ctDNA (−) | 0 | 33 | |||||||||
| Concordance depending on whether primary tumor or metastatic site was biopsied | |||||||||||
| Primary tumor (n = 31) | Metastatic sites (n = 9) | P value (primary tumor vs metastatic sites) | |||||||||
| (+/+) | (+/−, −/+) | (−/−) | Overall concordance | Kappa (SE) | (+/+) | (+/−, −/+) | (−/−) | Overall concordance | Kappa (SE) | ||
| TP53 | n = 4 | n = 11 | n = 16 | 64.5% | 0.17 (0.18) | n = 3 | n = 2 | n = 4 | 77.8% | 0.57 (0.24) | .69 |
| KRAS | n = 6 | n = 8 | n = 17 | 74.2% | 0.41 (0.17) | n = 2 | n = 0 | n = 7 | 100% | 1.00 (0.00) | .16 |
| PIK3CA | n = 2 | n = 4 | n = 25 | 87.1% | 0.45 (0.22) | n = 1 | n = 0 | n = 8 | 100% | 1.00 (0.00) | .56 |
| Concordance based on time interval between blood draw and tissue biopsy | |||||||||||
| ≤6 months (n = 27) | >6 months (n = 13) | P value (≤6 vs > 6 months) | |||||||||
| (+/+) | (+/−, −/+) | (−/−) | Overall concordance | Kappa (SE) | (+/+) | (+/−, −/+) | (−/−) | Overall concordance | Kappa (SE) | ||
| TP53 | n = 5 | n = 7 | n = 15 | 74.1% | 0.40 (0.19) | n = 2 | n = 6 | n = 5 | 53.8% | 0.03 (0.28) | .28 |
| KRAS | n = 7 | n = 5 | n = 15 | 81.5% | 0.60 (0.16) | n = 1 | n = 3 | n = 9 | 76.9% | 0.32 (0.25) | >.99 |
| PIK3CA | n = 3 | n = 3 | n = 21 | 88.9% | 0.61 (0.20) | n = 0 | n = 1 | n = 12 | 92.3% | 0.00 (0.00) | >.99 |
Note: Most common three genes in ctDNA sequencing were assessed at the gene level. P values in bold are those less than 0.05.
Abbreviation: ctDNA, circulating‐tumor DNA.
a
The closer the Kappa to 1, the more the concordance.