Mucinous histology as a predictive marker of 5-fluorouracil-based adjuvant chemotherapy for colon cancer

Purpose: The aim of this study was to evaluate the value of mucinous histology as a predictive marker of 5-Fluorouracil (FU)-based adjuvant chemotherapy in stage II, III colon cancer. Methods: Between January 1995 and December 2004, 987 patients who underwent curative resections for stage II, III sporadic colon cancer were classified into two groups, a mucinous carcinoma (MC) group and a non-mucinous carcinoma (NMC) group, based on the histology of the primary tumor. The differences in their clinicopathological characteristics and the prognostic impact of 5-FU-based adjuvant chemotherapy for various tumor histologies were analyzed. Results: Of the 987 patients, MCs accounted for 6.8% (68 patients). MCs were more frequently located in the Rt. Colon (P< 0.001) and were more frequently seen in young patients (less than 40 yr old) (P=0.028). The 5-yr survival rates between MC and NMC did not show any statistically significant difference. Patients, including both MC and NMC patients, who received 5-FU-based chemotherapy, revealed a better overall survival rate than patients with no adjuvant chemotherapy. In the multivariate analysis for the prognosis in NMC patients, 5-FU-based adjuvant chemotherapy, initial negative nodal status, and preoperative CEA <5 ng/mL were statistically significant prognostic factors (P values: <0.001, <0.001, and <0.001, respectively). In contrast, there was no statistically independent significance of 5-FU-based adjuvant chemotherapy in MC patients. Conclusion: In stage II and stage III sporadic colon cancer patients, response to 5-FU-based adjuvant chemotherapy in MC patients might be poor than it is in NMC patients.