Prognostic value of the ratio of carcinoembryonic antigen concentration to maximum tumor diameter in patients with stage II colorectal cancer.

BACKGROUND

Recently, a study from our center indicated that the ratio of preoperative carcinoembryonic antigen (CEA) concentration to maximum tumor diameter (DMAX) may be a prognostic marker for patients with rectal cancer. Therefore, the study aimed to evaluate whether this ratio (CEA/DMAX) has prognostic value for patients with stage II colorectal cancer (CRC).

METHODS

A prospectively maintained database was searched for patients with pathologically confirmed stage II CRC who underwent surgery between January 2010 and March 2019. Patients were stratified according to the mean CEA/DMAX value into low and high CEA/DMAX groups. Kaplan-Meier, univariable, and multivariable Cox regression analyses were used to evaluate whether the CEA/DMAX could predict overall survival (OS) and disease-free survival (DFS). Nomograms were constructed in terms of the results of multivariable Cox regression analyses.

RESULTS

The study included 2,499 patients with stage II CRC. The mean CEA/DMAX value was 2.33 (ng/mL per cm). Kaplan-Meier analyses revealed that, relative to the low CEA/DMAX group, the high CEA/DMAX group had significantly poorer OS (67.31% 85.02%, P<0.001) and DFS (61.41% 77.10%, P<0.001). The multivariable Cox regression analysis revealed that CEA/DMAX independently predicted OS (hazard ratio: 2.58, 95% confidence interval: 1.51-4.38, P<0.001) and DFS (hazard ratio: 1.97, 95% confidence interval: 1.38-2.83, P<0.001). Two simple-to-use nomograms comprising CEA/DMAX, age, T stage, and lymphovascular invasion were developed to predict 1-, 3-, and 5-year rates of OS and DFS among patients with stage II CRC. The nomograms had good performance based on the concordance index, receiver operating characteristic (ROC) curve analysis, and calibration curves. Subgroup analyses further confirmed that a high CEA/DMAX was associated with poor OS and DFS among patients with stage II colon cancer and among patients with stage II rectal cancer (both P<0.05).

CONCLUSIONS

Among patients with stage II CRC, a high CEA/DMAX independently predicted poor OS and DFS, and the predictive abilities were also observed in subgroup analyses of patients with stage II colon cancer or rectal cancer. Furthermore, we developed two nomograms that had good accuracy for predicting the prognosis of stage II CRC.