Fig. 3: Changes in CSF ctDNA maxVAF and CEA during treatment and their clinical correlations.

Line plots showing the changes in CSF ctDNA maxVAF (a) and CSF CEA (b) in patients (n = 86) who received at least one treatment. c Heatmap showing the concordance rates of ctDNA and CEA between two time intervals (T0–T1 and T1–T2) at different thresholds (0–30%). The upward and downward arrows indicate an increase and decrease in the maxVAF/VAF of ctDNA or the value of CEA, respectively. The boxed values highlight the concordance rates when the magnitude of CSF ctDNA changes (across all mutations) reached 20%. d The line graph (left) illustrates changes in the maxVAF of all mutations in CSF ctDNA from baseline (T0) to time point T1. Each line corresponds to an individual patient, with line color indicating treatment response: green for RE, red for NRE(PD), and blue for NRE(SD). The bar chart (right) shows the proportional distribution of different clinical responses between two groups: ctDNA response and ctDNA progression, as identified based on all mutations in CSF ctDNA. Bar color corresponds to treatment response: green for RE, red for NRE (SD), and yellow for NRE (PD). As observed, RE patients accounted for 90% in the ctDNA response group, indicating a concordance rate of 90%; similarly, NRE patients accounted for 93.3% in the ctDNA progression group, corresponding to a concordance rate of 93.3%. e The figure presents results corresponding to those in d, derived from EGFR mutations in CSF ctDNA. f The figure displays results corresponding to those in d, obtained from changes in CEA levels in plasma and CSF. Specifically, CEA response or progression was defined as a 20% decrease or increase in plasma or CSF CEA levels, respectively. Abbreviation: CEA carcinoembryonic antigen, CSF cerebrospinal fluid, ctDNA circulating tumor DNA, maxVAF max variant allele frequency, PD progressive disease, NRE non-responses, RE responses, SD stable disease.