The prognostic significance of preoperative carcinoembryonic antigen levels in colorectal cancer. Results from NSABP (National Surgical Adjuvant Breast and Bowel Project) clinical trials.

This analysis explores the prognostic significance of preoperative carcinoembryonic antigen (CEA) levels in patients with colorectal cancer. The data were derived from 945 patients entered into two randomized prospective clinical trials of the National Surgical Adjuvant Breast and Bowel Project. A strong correlation was evident between preoperative CEA level and Dukes class. The mean CEA progressively increased with each Dukes category and the mean value for each of the four classes was significantly different. This relationship was prevalent whether the data were analyzed for all colorectal lesions regardless of location or specifically for right-sided colon tumors. The prognostic function of preoperative CEA level was independent of the number of positive histologic nodes. Preoperative CEA level correlated with the degree of lumen encirclement by tumor. Tumors that did not encircle more than one half the lumen were associated with significantly lower preoperative CEA levels than those that did. The presence or absence of lumen obstruction was unrelated to the preoperative CEA level. The relative risk of developing a treatment failure was associated with preoperative CEA, in both Dukes B and C patients, demonstrating that the prognostic significance of preoperative CEA was independent of Dukes class.