Factors predicting long-term survival in colorectal cancer patients with a normal preoperative serum level of carcinoembryonic antigen.

PURPOSE: The aim of this study was to determine which clinicopathological factors influenced the long-term survival after potentially curative resection of colorectal cancer patients with a normal preoperative serum level of carcinoembryonic antigen (CEA).
METHODS: A total of 1,732 patients who underwent curative surgery for primary nonmetastatic colorectal cancers from 1997 to 2009 were analyzed. Of these patients, 1,128 (65.1 %) had normal level of preoperative CEA (<5 ng/mL). The predicting factors for survival were analyzed.
RESULTS: When the serum CEA cutoff value was set at 2.4 ng/mL (median value), the high CEA groups displayed a higher percentage of older patients, males, large-diameter tumors, advanced T and N categories, and positive perineural invasion, compared to the low CEA groups. Multivariate analysis revealed that age, T category, N category, number of lymph nodes retrieved, operative method, lymphovascular invasion, perineural invasion, postoperative chemotherapy, and preoperative serum CEA level ≥ 2.4 ng/mL were independent predictors for 5-year overall survival, while tumor location, tumor size, T category, N category, lymphovascular invasion, and perineural invasion were independent predictors for 5-year disease-free survival.
CONCLUSIONS: Even if patients with colorectal cancer have a normal preoperative CEA before surgery, CEA may be useful for prognostic stratification using 2.4 ng/mL as the cutoff.