Effectiveness of Adjuvant Chemotherapy with 5-FU/Leucovorin and Prognosis in Stage II Colon Cancer.

PURPOSE

The aims of this study were to investigate the survival results and the prognostic factors of adjuvant chemotherapy in stage II colon cancer in the sparsity of Korean data.

METHODS

From 1993 to 2006, 363 curatively resected pathologic stage II colon cancer patients were enrolled. Six cycles of adjuvant chemotherapy was performed: intravenous bolus 5-fluorouracil (5-FU) 500 mg/m(2) with leucovorin 20 mg/m2 for 2 hours daily for 5 days, followed by a 3-week resting period (n = 308). Fifty-five patients received only curative surgery. A high risk of recurrence was defined as the presence of one or more of the following factors: T4 tumor, lympho-vascular invasion, perineural invasion, perforation, obstruction, retrieved lymph node < 12, and poorly differention. The median follow-up period was 68 months (1 to 205 months).

RESULTS

The five-year overall survival (OS) rate was 90.1%, and the five-year disease-free survival (DFS) rate was 84.7%. Among high-risk patients, the OS and the DFS rates of the treatment group were significantly higher than those of the non-treatment group (OS: 90.6% vs. 69.1%, P < 0.0001; DFS: 85.9% vs. 54.1%, P < 0.0001). Among low-risk patients, the survival results of the treatment group were also significantly superior (OS: 97.7% vs. 88.2%, P < 0.0001; DFS: 93.0% vs. 80.0%, P = 0.001). In the multivariate analysis, adjuvant chemotherapy was a significantly favorable prognostic factor for overall survival (hazard ratio, 0.41; 95% confidence interval, 0.22 to 0.75; P = 0.004).

CONCLUSION

In our population, adjuvant chemotherapy showed superior survival to curative surgery alone and significantly reduced the risk of death. A nationwide multicenter randomized trial is needed.