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Table 3 GAs and factors affect the detection of GAs in the plasma ctDNA assay

From: Clinical utility of tumor genomic profiling in patients with high plasma circulating tumor DNA burden or metabolically active tumors

FoundationACT Group A (N = 14) Group B (N = 67) Total (N = 81)
Specimen type Frozen plasma Fresh whole blood All samples
Volume (mL) ~ 3.0 8.5 (5.5–11.5) 8.0 (3.0–11.5)
cfDNA (ng/mL) 2.5 ± 5.0 14.2 ± 32.2 P = 0.023
GA ≥ 1 13 (93%) 56 (84%) 69 (85%)
Total number of GAs (average/case, range) 49 (3.5/case; 1–9) 166 (2.5/case; 1–11) 215 (2.7/case; 1–11)
 Base substitutions 36 (73%) 118 (71%) 154 (72%)
 Insertions/deletions 8 (16%) 26 (16%) 34 (16%)
 Amplifications 1 (2%) 13 (8%) 14 (7%)
Rearrangements/fusions 4 (8%) 9 (5%) 13 (6%)
cfDNA (mean ± SD) ng/mL; (GA ≥ 1 vs GA = 0) 3.1 ± 5.9 vs 0.3 ± 0.1 (P = 0.5293) 8.6 ± 18.1 vs 18.9 ± 51.6 (P = 0.2314) 7.6 ± 16.7 vs 16.3 ± 47.3 (P = 0.2362)
MSAF (mean ± SD); (GA ≥1 vs GA = 0) 0.0648 ± 0.0823 vs 0.0005 ± 0.0007 (P = 0.3062) 0.1219 ± 0.2031 vs 0.0003 ± 0.0009 (P = 0.0432) 0.1117 ± 0.1880 vs 0.0003 ± 0.0009 (P = 0.0304)
Tumor burden by RECIST V1.1 cm (GA ≥ 1 vs GA = 0) (mean ± SD) 7.6 ± 6.4 vs 12.0 ± 12.0 (P = 0.4610) 9.8 ± 5.8 vs 5.7 ± 3.4 (P = 0.0292) 9.4 ± 5.9 vs 6.6 ± 5.3 (P = 0.1301)
Tumor metabolic activity by SUVmax mg/dL (GA ≥1 vs GA = 0) (mean ± SD) 51.1 ± 34.8 vs 31.2 ± 30.7 (P = 0.4772) 48.1 ± 29.5 vs 14.3 ± 12.6 (P = 0.0006) 48.6 ± 30.2 vs 16.9 ± 15.8 (P = 0.0006)
  1. GAs genomic alterations, cfDNA cell-free DNA, MSAF maximum somatic allele frequency, SUVmax maximum standardized uptake value