Fig 1.
One-point assessment of ctDNA and carbohydrate antigen 19–9 (CA19-9) before treatment to assess recurrence and prognosis.
(A) Recurrence-free survival (RFS) curves according to the presence of KRAS-mutated ctDNA and CA19-9 level before surgery in 39 patients who underwent surgery (P = 0.38 and 0.7 by log-rank test). (B) Overall survival (OS) curves according to the presence of KRAS-mutated ctDNA and CA19-9 level before first-line chemotherapy in 26 chemotherapy-naïve patients who did not undergo surgery (P = 0.07 and 0.86 by log-rank test). X-axes indicate the months from surgery, whereas Y-axes indicate the probability of RFS or OS.
Fig 2.
Sequential assessments of KRAS-mutated ctDNA and carbohydrate antigen 19–9 (CA19-9) level in longitudinal tests.
(A) CA19-9 levels and the emergence of KRAS-mutated ctDNA are shown under “CA19-9” and “KRAS-mutated ctDNA,” respectively, and are ordered as per the timing of blood examination after surgery (1→12). CA19-9 ≤37 U/mL and no detection of KRAS-mutated ctDNA are represented in blue, whereas CA19-9 >37 U/mL and the emergence of KRAS-mutated ctDNA are represented in red. Recurrence is shown under “Rec,” with “no” and “yes” indicated in white and gray, respectively. Prognosis is shown under “Outcome,” with “alive” and “death” indicated in white and gray, respectively. Examination results for every 3 months are shown in one cell; thus, four cells correspond to approximately 1 year. ND, not determined. (B) Sequential assessments of KRAS-mutated ctDNA and CA19-9 levels in longitudinal tests for patients who did not undergo surgery. CA19-9 levels and the emergence of KRAS-mutated ctDNA are ordered as per the timing of blood examination (1→15). Number of patients corresponds to those described in S2 and S3 Tables.
Fig 3.
Outcome according to KRAS-mutated ctDNA and CA19-9 in longitudinal evaluations.
(A) Simon–Makuch plot for the effect of emergence of KRAS-mutated ctDNA on overall survival (OS) in patients who underwent surgery, illustrated by a landmark at 8 months, the median time point for the detection of KRAS-mutated ctDNA (P<0.001). (B) Simon–Makuch plot for the effect of CA19-9 level on OS in patients who underwent surgery, illustrated by a landmark at 4 months, the median time point for CA19-9 level increasing to >37 U/mL (P = 0.03). (C) Simon–Makuch plot for the effect of emergence of KRAS-mutated ctDNA on OS in patients who did not undergo surgery, illustrated by a landmark at 2 months, the median time point for the detection of KRAS-mutated ctDNA (P<0.001). X-axes in Fig 3A and 3B indicate the months from surgery, X-axis in Fig 3C indicates the months from the initial evaluation in this study, whereas Y-axes indicate the probability of survival.
Table 1.
Univariate and multivariate analyses of overall survival in patients who underwent surgery.
Table 2.
Univariate and multivariate analyses of overall survival in patients who did not undergo surgery.
Fig 4.
Sequential assessments of KRAS-mutated ctDNA within a short period to assess outcome.
(A) Overall survival (OS) curves according to the emergence of KRAS-mutated ctDNA within 1 year after surgery (P<0.001 by log-rank test). (B) Progression-free survival (PFS) curves according to the emergence of KRAS-mutated ctDNA within 6 months of chemotherapy (P<0.001 by log-rank test). X-axes indicate the months from surgery and diagnosis, whereas Y-axes indicate the probability of OS and PFS.