Table 3.
Univariable and multivariable Cox regression analyses predicting overall survival in 58 patients with metastatic pancreatic ductal adenocarcinoma
| Univariable | Multivariable VAF ctDNA | Multivariable tumor volume | ||||
|---|---|---|---|---|---|---|
| HR (95% CI) | p | HR (95% CI) | p | HR (95% CI) | p | |
| Age (per year increase) | 1.02 (0.99–1.05) | 0.202 | – | – | – | – |
| ECOG performance score1 | ||||||
| 0–1 | 1 | – | – | – | ||
| 2–3 | 1.37 (0.74–2.54) | 0.319 | ||||
| Increasing CA19.9 (per 1,000 kU/L increase) | 1.00 (1.00–1.01) | 0.073 | 1.00 (1.00–1.01) | 0.147 | 1.00 (1.00–1.01) | 0.039 |
| Vascular involvement primary tumor2 , 3 | ||||||
| No | 1 | – | – | – | – | |
| Yes | 0.94 (0.50–1.81) | 0.856 | ||||
| Localization metastases on baseline imaging3 | ||||||
| No or distant lymph nodes only | 1 | |||||
| Liver metastases4 | 1.59 (0.77–3.29) | 0.210 | – | – | – | – |
| Other metastases | 1.15 (0.46–2.89) | 0.763 | ||||
| Palliative chemotherapy | ||||||
| No | 1 | 1 | 1 | |||
| First line FOLFIRINOX5 | 0.37 (0.19–0.75) | 0.005 | 0.34 (0.16–0.71) | 0.004 | 0.29 (0.14–0.61) | 0.001 |
| First line gem‐nab5 | 0.43 (0.20–1.92) | 0.030 | 0.48 (0.22–1.06) | 0.070 | 0.43 (0.19–0.95) | 0.024 |
| Increasing cfDNA concentration | 1.02 (0.96–1.08) | 0.559 | – | – | – | – |
| NGS ctDNA detected | ||||||
| No | 1 | 0.009 | – | – | – | – |
| Yes | 2.16 (1.21–3.85) | |||||
| VAF ctDNA (per 1% increase) | 1.06 (1.03–1.09) | 0.001 | 1.05 (1.01–1.09) | 0.005 | 6 | |
| Total tumor volume (per 10 mL increase) | 1.03 (1.01–1.04) | 0.001 | 6 | 1.00 (1.01–1.05) | 0.003 | |
| Primary tumor volume (per 10 mL increase) | 1.03 (1.01–1.05) | 0.003 | 6 | 6 | ||
| Metastases volume (per 10 mL increase) | 1.06 (1.01–1.11) | 0.014 | 6 | 6 | ||
1
When analyzing ECOG performance status using each score as a separate category (0, 1, 2, 3; 0 = ref) only ECOG 3 (n = 3) was a significant prognostic factor (HR 8.6, p = 0.002); VAF, variant allele frequency (highest VAF of detected mutations per patients used for analyses).
2
Vascular involvement was defined as involvement of the coeliac trunc, hepatic artery, superior mesenteric artery, portal vene, superior mesenteric vene or splenic vene.
3
On baseline imaging.
4
With or without metastases to other organs.
5
At least one completed cycle of chemotherapy.
6
Not included to avoid multicollinearity.