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Background: The metastatic potential of tumors is dependent on the cell to cell adhesion by cell surface carbohydrate antigens. Thus, expression of sialyl Lewis a , which is one of the important molecules of cell surface carbohydrates, may serve as a prognostic marker of aggressive and metastasizing tumor growth. However, the prognostic value of sialyl Lewis a expression in colon cancer is still controversial. Methods: In this study, we investigated the expression of sialyl Lewis a antigen in 233 colon cancer specimens from patients who were registered in a prospective adjuvant immunochemotherapy clinical trial. The clinical course and the prognosis of the patients were evaluated after all the immunohistochemical analyses had been performed. Results: Sialyl Lewis a expression levels were correlated with both overall survival (P= 0.0006) and disease-free survival (P = 0.004) in all patients with the log-rank test. This result could be assumed to have been influenced by the difference in the metastatic preponderance in a high versus low sialyl Lewis a expression in the tumor cells. Conclusion: This prospective study in a randomized controlled trial suggests that sialyl Lewis a expression levels may serve as an indicator of the metastatic potential of colon cancer cells, which would strongly predict the prognosis.

Background: Oral 5-fluorouracil and its prodrugs (tegafur, carmofur) is now being studied for adjuvant chemotherapy of curatively resected colorectal cancers.To evaluate the effect of these oral fluoropyrimidines (o-FPs), an individual patient data (IPD) meta-analysis of randomized clinical trials was performed in Japan as an inter-trialist group study. Methods: Data from the three clinical trials in which postoperative adjuvant therapy with o-FPs was compared with surgery alone in patients with colorectal cancer were sought. IPD from a total of 4960 patients with follow-up periods of at least 5 years were analyzed. Results: The results of the meta-analysis on an 'intention to treat' basis demonstrated a significant benefit of o-FPs in terms of the disease-free survival (DFS) of the total patients [risk ratio (RR) 0.830,95 % confidence interval (CI) 0.742-0.929, P = 0.001J. o-FPs were also demonstrated to be effective for survival in rectal cancer (RR 0.857, 95% CI 0.734-0.999, P = 0.049) and in Dukes'C colorectal cancer (RR 0.828,95 % CI 0.711-0.965, P= 0.016). Conclusion: The results suggest the advantage of long term o-FPs, possibly with the injection of mitomycin C, for prognosis for curatively resected colorectal cancer patients.