Table 1.
Pre-treatment patient characteristics and cfDNA/ctDNA levels in plasma.
| Baseline Characteristics | Patients available for total DNA analysis (n = 24) | Patients available for ctDNA analysis (n = 22) | ||||
|---|---|---|---|---|---|---|
| No of patients | Alleles per mL plasma (CHR3/gCYC assay) Median (range) | p-value | Patients | Mutated alleles per mL plasma. Median (range) | p-value | |
| Age (median/range) | 64.5 (29–81) | 64.5 (45–81) | ||||
| <Median | 11 | 5437 (876–72286) | 0.73 | 11 | 69 (8,2–15400) | 0.12 |
| >Median | 11 | 4733 (833–43029) | 11 | 513 (44–24231) | ||
| Gender | ||||||
| Female | 11 | 5400 (833–72286) | 0.62 | 10 | 94 (23–15400) | 0.77 |
| Male | 13 | 5457 (876–42783) | 12 | 179 (8–24231) | ||
| ECOG Performance status | ||||||
| 0 | 14 | 5428 (876–72286) | 14 | 108 (8–15400) | ||
| 1 | 7 | 5400 (833–16733) | 0.37 | 5 | 1120 (81–3086) | 0.55 |
| 2 | 1 | 3217 | 0.67 | 1 | 59 | 0.67 |
| Unknown | 2 | 21386 (7696–35074) | 0.5 | 2 | 12127 (23–24231) | 0.93 |
| Sites of metastatic disease | ||||||
| Liver metastasis | 12 | 19149 (876–72286) | 0.04* | 12 | 684 (23–23231) | 0.16 |
| No liver metastasis | 12 | 4508 (833–16733) | 10 | 91 (8–3086) | ||
| Lung metastasis | 11 | 5457 (833–43029) | 0.50 | 10 | 381 (8–24231) | 0.58 |
| No lung metastasis | 13 | 5400 (933–72286) | 12 | 104 (23–15400) | ||
| Mutation status of tumour | ||||||
| WT | 7 | 3617 (833–30600) | 5 | 69 (27–513) | ||
| KRAS mut | 12 | 6268 (1857–72286) | 0.05* | 12 | 1803 (8–24231) | 0.33 |
| NRAS mut | 3a | 16733 (4067–42783) | 0.17 | 3a | 107 (101–10199) | 0.39 |
| BRAF mut | 3a | 2108 (933–4067) | 0.65 | 3a | 107 (81–109) | 0.79 |
| Number of metastatic sites | ||||||
| 1 | 12 | 4742 (876–72286) | 12 | 91 (23–15400) | ||
| 2 | 10 | 5400 (833–40629) | 0.77 | 6 | 817 (8–24231) | 0.21 |
| >3 | 2 | 36814 (30600–43029) | 0.20 | 4 | 1652 (59–11242) | 0.45 |
| Treatment efficacy, 1. RECIST | ||||||
| Stabil disease (SD) | 19 | 5457 (833–72286) | 0.52 | 17 | 248 (8–24231) | 0.16 |
| Partial/complete response (PR/CR) | 5 | 4067 (2610–5620) | 5 | 44 (27–2486) | ||
| Progression disease (PD) | 0 | 0 | ||||
Wilcoxon rank sum test was applied to test for correlations between patient characteristics and cfDNA and ctDNA. aTwo patients were excluded (see Fig. 1A) and hence data from n = 22 patients is shown. bOne patient (pt109) had a colon tumour with a BRAF mutation and a rectum tumour with a NRAS mutation. p-values < 0.05 are indicated in bold and with *.
ctDNA, circulating tumour DNA; cfDNA, cell-free DNA, ECOG, Eastern Cooperative Oncology Group; RECIST, Response Evaluation Criteria In Solid Tumours.