Moreover, cfDNA levels were significantly higher in patients with lymph node involvement (median: 7569 vs. 5492 copies/mL, p < 0.001), lymphovascular invasion (median: 7569 vs. 5768 copies/mL, p = 0.0029), abnormal serum CEA level (median: 11,627 vs. 6338 copies/mL, p < 0.001), and stage II and III cancer (median: 6893 vs. 5697 copies/mL, p = 0.0028) (Table 1). Here, CEACAM5 is linked to cancer.