Table 4.

Concordance assessment of KRASG12/G13 mutations in plasma cfDNA and FFPE tumor tissue or urine cfDNA from patients with advanced cancers

Concordance for plasma samples collected before systemic therapy tested for KRASG12/G13 mutations versus FFPE tumor samples tested in the clinical laboratory
Number of patients, N = 33KRASG12/G13 mutation in tumorKRASG12/G13 wild-type in tumor
KRASG12/G13 mutation in plasma, number of patients220
KRASG12/G13 wild-type in plasma, number of patients29
Observed concordance31 (94%); kappa, 0.86; SE, 0.10; 95% CI, 0.67–1.00
Sensitivity92% (95% CI, 0.73–0.99)
Specificity100% (95% CI, 0.66–1.00)
PPV100% (95% CI, 0.85–1.00)
Concordance for plasma and urine samples collected before systemic therapy tested for KRASG12/G13 mutations
Number of patients, N = 33KRASG12/G13 mutation in plasmaKRASG12/G13 wild-type in plasma
KRASG12/G13 mutation in urine, number of patients132
KRASG12/G13 wild-type in urine, number of patients99
Observed concordance22 (67%); kappa, 0.35; SE, 0.15; 95% CI, 0.07–0.64
Sensitivity59% (95% CI, 0.36–0.79)
Specificity82% (95% CI, 0.48–0.98)
PPV87% (95% CI, 0.60–0.98)