Table 4.

Multivariate Cox regression analysis of PFS and OS

PFSOS
VariablesHR (95% CI)PHR (95% CI)P
cfDNA quartile (1–4)a1.3 (1.1–1.6)0.0051.7 (1.4–2.1)<0.00001
PSa1.3 (0.9–1.8)0.111.5 (1.1–2.2)0.014
KRAS status in tumor
 Wild-typeb1<0.0000110.047
 Mutation2.7 (1.7–4.4)1.6
Number of metastatic sites
 1–2b10.002410.001
 >22.0 (1.3–3.2)2.2 (1.4–3.6)
Anatomic site
 Colonb10.087
 Rectum0.7 (0.4–1.06)
  • aEntered in the model as numeric variables. The quartiles (1–4) were used for grouping of cDNA levels, and HRs consequently correspond to one-step increase in quartiles. PS was divided into 0, 1, and 2. (No patients with PS 3 were included in the study.)

  • bReference group.