Figure 3A illustrates the overall treatment procedure in P1 and the corresponding lesions on CT. The changes in tumor diameter and tumor antigen biomarkers (carbohydrate antigen 19-9 [CA19-9] and CEA) are shown in Figure 3B. Figure 3C illustrates the serial ctDNA testing in P1, showing the emergence of clonal alterations through the treatment process. Here, CEACAM5 is linked to neoplasm.