Novel tumor marker index using carcinoembryonic antigen and carbohydrate antigen 19-9 is a significant prognostic factor for resectable colorectal cancer

Abstract

We evaluated the usefulness of a newly devised tumor marker index (TMI), namely, the geometric mean of normalized carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9), in determining colorectal cancer (CRC) prognosis. This retrospective cohort study included 306 patients with stages I–III CRC who underwent elective laparoscopic resection between April 2010 and March 2020. Survival rates and risk factors of relapse-free survival (RFS) and cancer-specific survival (CSS) were analyzed using Kaplan–Meier curves and Cox proportional hazards model. High-TMI group (122 patients) had significantly lower rates (95% confidence interval [95% CI]) for 5-year RFS (89.7%, 83.9–93.5 vs. 65.8%, 56.3–73.8, p < 0.001) and CSS (94.9%, 89.4–97.6 vs. 77.3%, 67.7–84.4, p < 0.001) than low-TMI group. Multivariate analysis (hazard ratio [95% CI]) indicated ≥ T3 disease (RFS: 2.69, 1.12–6.45, p = 0.026; CSS: 7.64, 1.02–57.3, p = 0.048), stage III CRC (RFS: 3.30, 1.74–6.28, p < 0.001; CSS: 6.23, 2.04–19.0, p = 0.001), and high TMI (RFS: 2.50, 1.43–4.38, p = 0.001; CSS: 3.80, 1.63–8.87, p = 0.002) as significant RFS and CSS predictors. Area under the curve (AUC) of 5-year cancer deaths (0.739, p < 0.001) was significantly higher for TMI than for CEA or CA19-9 alone. Preoperative TMI is a useful prognostic indicator for patients with resectable CRC.