The prognostic value of carcinoembryonic antigen in early-onset locally advanced rectal cancer patients

Shen Cailu; Shen Di; Xu Tong; Ge Xiaosong

doi:10.3969/j.issn.1671-6450.2025.05.007

Abstract：Objective To evaluate the effect of pre-treatment serum CEA levels on the survival of patients with early-onset locally advanced rectal cancer(EO-LARC)and to develop a prognostic prediction model by using the SEER da-tabase.Methods A total of 2329 patients diagnosed with EO-LARC through biopsy pathology from 2005 to 2020 were se-lected as the research subjects.Based on the qualitative results of pre-treatment serum CEA levels from the SEER database,patients were categorized into a CEA-positive group(n=945)and a CEA-negative group(n=1384).Propensity Score Matc-hing(PSM)was performed at a 1∶1 ratio,yielding 918 matched patients in each group.The impact of pre-treatment serum CEA levels on cancer-specific survival(CSS)and overall survival(OS)in EO-LARC patients was analyzed.A Cox propor-tional hazards regression model was used to identify factors associated with EO-LARC patient survival,and a nomogram was developed to predict 10-year cancer-specific survival.The model's calibration was evaluated using calibration curves to compare predicted and observed outcomes,while its discriminatory ability was assessed using the time-dependent area under the receiver operating characteristic curve(ROC-AUC).Results The comparison of baseline characteristics between the matched groups showed no statistically significant differences(P＞0.05).Cox regression analysis identified gender,tumor TNM stage,number of lymph nodes dissected,histological grade,pre-treatment CEA level,and the sequence of radiotherapy and surgery as independent prognostic factors for CSS[HR(95％ CI)=1.617(1.232-2.124),0.706(0.513-0.971),1.748(1.324-2.307),0.504(0.370-0.687),0.605(0.457-0.800),0.650(0.430-0.984)].Similarly,gender,tumor TNM stage,number of lymph nodes dissected,histological grade,and pre-treatment CEA level were identified as independent prognostic factors for OS[HR(95％CI)=1.508(1.166-1.950),0.713(0.526-0.965),1.723(1.321-2248),0.522(0.387-0.705),0.580(0.443-0.761)].A novel staging system was developed by integrating pre-treatment CEA levels with tumor TNM staging,revealing that patients with CEA-negative stage Ⅱ tumors had the best prognosis,while those with CEA-positive stage Ⅲtumors had the worst prognosis.The differences in both CSS and OS among the groups were statistically significant(P＜0.001).The nomogram developed based on independent prognostic factors achieved ROC-AUC of 0.717(95％ CI:0.648-0.786)in the training cohort and 0.675(95％ CI:0.563-0.787)in the validation cohort,respectively.These results were su-perior to those of the novel staging[AUC(95％ CI)=0.657(0.584-0.730)in the training cohort and 0.629(0.512-0.746)in the validation cohort],tumor TNM stage[AUC(95％CI)=0.593(0.525-0.662)in the training cohort and 0.593(0.499-0.687)in the validation cohort],and pre-treatment CEA levels[AUC(95％CI)=0.606(0.539-0.673)in the train-ing cohort and 0.584(0.481-0.688)in the validation cohort].Conclusion CEA positivity is strongly associated with poor prognosis in EO-LARC patients.The prognostic nomogram for EO-LARC,developed based on factors including race,gen-der,novel staging system,number of lymph nodes dissected,histological grade,and the sequence of radiotherapy and surgery,demonstrates effective stratification of patient outcomes.Pre-treatment CEA levels should be regarded as a key monitoring indicator for EO-LARC patients.