Table 4.
Joint modelling of longitudinal ctDNA level and time to first progression. Based on 81 patients with a total of 298 ctDNA observations. Statistically significant P values are in bold.
| Survival submodel | HR (95% CI) | P value |
|---|---|---|
| Study site (SUH vs. HUH) | 1.36 (0.54–3.42) | 0.51 |
| Sex (male vs. female) | 1.43 (0.84–2.46) | 0.19 |
| Age (per year) | 0.97 (0.95–1.00) | 0.081 |
| ECOG status | ||
| 0 | Reference | |
| 1 | 0.53 (0.27–1.03) | 0.061 |
| 2 | 2.05 (0.86–4.85) | 0.11 |
| Treatment | ||
| FOLFIRINOX | Reference | |
| Nab‐paclitaxel/gemcitabine | 2.20 (1.08–4.76) | 0.026 |
| Gemcitabine | 4.57 (1.62–12.7) | 0.004 |
| Metastasis location | ||
| None | Reference | |
| Other organs than liver | 1.80 (0.71–4.62) | 0.21 |
| Liver | 2.23 (1.02–5.26) | 0.046 |
| ctDNA level (per unit) | 1.21 (1.09–1.34) | < 0.001 |
| Longitudinal submodel | β (95% CI) | P value |
|---|---|---|
| Time since baseline | ||
| Spline 1 | −1.55 (−2.85, −0.19) | 0.025 |
| Spline 2 | 0.38 (−1.56, 2.28) | 0.72 |
| Spline 3 | 7.18 (3.69, 10.5) | < 0.001 |
| Time since infusion | ||
| > 7 days | Reference | |
| 3–7 days | −0.01 (−0.95, 0.94) | 0.44 |
| 1–2 days | 0.63 (−0.99, 2.28) | 0.99 |