Preoperative carcinoembryonic antigen level as an independent prognostic factor in colorectal cancer: Taiwan experience

Background: Preoperative carcinoembryonic antigen (CEA) level is considered as a factor predictive of survival in colorectal cancer patients. Patients with normal (<5 ng/ml) or lower preoperative CEA levels were reported to h ave significantly longer survival. This study was carried out in an effort to evaluate the prognostic significance of preoperative CEA levels of patie nts with colorectal cancer in Taiwan, Methods: Between 1990 and 1994, 218 patients with histologically confirmed colorectal cancers were evaluated retrospectively at the Veterans General H ospital-Taipei. All the patients had undergone potentially curative surgery . Patients with metastatic diseases were not included. 5-Fluorouracil-based adjuvant chemotherapy was administered if the patients had Dukes' C diseas e. Reference to the Dukes' classification was according to the classical cr iteria described in 1932 for carcinoma of the rectum and adapted for use in colonic tumors. Data on gender, age, degree of tumor differentiation, loca tion of the tumor, tumor size, lymph node metastasis, penetration of the bo wel wall and preoperative CEA levels were analyzed to determine their assoc iation with survival. Blood samples for CEA measurement were taken a few da ys before operation and were analyzed using the radioimmunoassay method. Mu ltivariate analysis by Cox's proportional hazards regression model was perf ormed to determine the most important predictors of survival among all of t he possible variables. Results: By univariate analysis, the size of the tumor (p = 0.012), lymph n ode metastases (p = 0.007), penetration of the bowel wall (p < 0.001) and p reoperative CEA levels (p < 0.001) were found to be significant prognostic factors, while gender, age, degree of tumor differentiation and location of the tumor were not significant. By multivariate Cox analysis, lymph node m etastases (p = 0.003), penetration of the bowel wall (p = 0.0001) and preop erative CEA levels (p = 0.0001) were found to be independent prognostic fac tors in colorectal cancer patients. Conclusions: The data from our study indicate that in addition to lymph nod e metastases and penetration of the bowel wall, the preoperative CEA levels are also an independent prognostic factor in non-metastatic colorectal can cer patients after curative surgery. This could serve as an appropriate mod ification to the initial Dukes' scheme in colorectal cancer.